86rs

Im building a motor for my brother in laws 84 Z28. I have a 305 and 307 motor both complete just need tore down and machined. I just need to know which one would be the better motor to build goin for a mild street rig. Both motors where FREE so i dont want to hear "just go buy a 350".
Thanks for any help.

Apeiron

Doesn't matter if it's free, the block is one of the cheapest parts.

ATX-Iroc

I have a 305 so i no it hurts when someone says it but there not worth the time and if the one you have needs work its much cheaper to buy a good 305. I've thrown away 2 perfectly good 305s after asking for 50 bucks for the pair, offer someone 20 bucks and theyll sell you a good one.

sofakingdom

iTrader: (1)

If you're going to "rebuild" a short block, THINK about what you're about to do.

You're going to spend money on a bunch of machine work; $600 - $750 MINIMUM for anything resembling a quality job. You're going to spend hours and hours chasing down parts, cleaning stuff, fitting, assembling, and so on. You're going to have to buy $450 MINIMUM worth of parts, even if you go with THE ABSOLUTE CHEEEEEEEEEEEPEST of everything; pistons, rings, bearings, gaskets, cam, oil pump, incidentals that nickel-&-dime you to death. You're going to tear your car all apart and disable it for who knows how long. You're taking a risk that something will go wrong; the crank could be about to break, something might not fit, some part might not assemble quite right and you don't notice it, and the whole thing turn to shrapnel shortly after you install it, hopefully not, but MAYBE. And worst of all, what happens after you get it all done and it's .... just ..... not .......... quite ..... all you'd hoped it would be? What if you're disappointed? What if your bud at work spends EXACTLY the same amount of money as you or maybe even LESS, but makes different (wiser) decisions, and KICKS YOUR BUTT? What then? You can't take all that machine work and whatnot, and transplant it to some other motor, now can you? You're stuck, and the ONLY way to fix it, is to then start over.

Meanwhile, the block you start out with, is THE ABSOLUTE LEAST COSTLY PART of the whole project. You'll spend more on GASKETS than a block core costs. In fact you can easily spend more just on THE DIFFERENCE BETWEEN different types of head gaskets, than a block core costs. You will spend more on a cherry picker, more on shop supplies, maybe even more on PAINT. IOW, the cost of the block core COMPLETELY DISAPPEARS into the noise.

Now... I'm real dumb and all, I don't have a problem telling you that, because it's pretty obvious anyway; but if I'm spending THAT MUCH money, taking THAT MUCH risk, and doing THAT MUCH work, I like to be reasonably assured UP FRONT that I'm going to get THE MOST POSSIBLE results at the end in exchange. Makes sense, eh?

So in what way is using a "free" block, that costs THE EXACT SAME AMOUNT to build or maybe even MORE (because nobody with any brains ever does it, so all the parts cost more and there's a TINY fraction of the choices), better than spending a whole $50 or something on a 350 core?

I know you said you don't want to hear it, but you're giong to hear it anyway. The CHEEEEEEEEEEEEEEPEST power money can buy, is CUBIC INCHES. Throw those little weenie motors in the trash, spend the whole ungodly $50 on a 350 core, and get THE MOST results you possibly can for all that money you're ALREADY GOING TO SPEND. Building those things is just not very bright, speaking directly from personal experience.

camaronewbie

I agree - like it or not, given that these blocks were "free" - you got what you paid for ... nothing.

AlkyIROC

A choice between a 305 and a 307 is a coin flip. Both are not really worth rebuilding. Just because you already have them doesn't mean they're worth rebuilding. If you picked either of them up for free, there's a reason they're usually free. Nobody wants them so it's cheaper to just give them away.

A junkyard 350 core is a better starting point considering the cost to do a total rebuild is about the same. Then again, the cost of a reman engine will probably be even cheaper. Depends how far you want to go with a rebuild.

86rs

The car has no motor so its not a waste of time to do it. I have the tools and supplies and knowledge to do it. Both motors where his dads before he passed so they have value to him. If i go buy a 350 i still have to pay for machineing so wats the point in that and not everybody wants a 350. So back to my question which do u think would be a better motor and maybe a little bit more spunkier.

AlkyIROC

That's your best answer if you're dead set on a 305 or a 307. About the only advantage of the 305 is that there's a few more replacement parts available for it and it has slightly better aftermarket choices. Both are boat anchors but the 307 should stay at the bottom of the lake.

86rs

Building those things is just not very bright[/quote]

Thats about the dumbest thing i have ever heard. If it wasnt bright to build a motor then no one would do it and every one would spend there money on some turn key motor. But people dont people have Pride in wat they build me and my brother in law have pride in our motors and cars we fix up. Its that extra effert that makes something yours and to be proud of!

Apeiron

He didn't say it wasn't bright to build a motor. He said it wasn't bright to build one of those, ie. a 305 or 307.

If you don't want to listen to advice, then knock yourself out building whichever one you want. You can make either one run well, but you won't get the best possible return on your money and effort.

Otherwise, spend your extra effort on building a 350 or even a 383. It costs you 5% more money to add a used bare block to the project, but when you're done you've got 20% more engine. You have something you can be just as proud of either way.

86rs

WOW can u guys not read my brother in law dont want a 350 or any other motor he wants the 305 or 307 thats it so stop tellin me to get a 350.I want advice on cams heads things like that from people that might have one or have built one.Not advice on a 350 does the title say anything about a 350 NO so stop preaching to me about the 350. Yes i under stand that for the same money i can get more power but its not my car and those are the motors he wants.

DeathStarr89

iTrader: (1)

305, slap some good heads on it with a moderate cam, headers and a good intake. Sure you won't make the same power as the same parts on a 350 but it'll be better than a non-running car.

Apeiron

Then what years are the blocks and what heads do they have now?

n2deep22

Get a 350 lol

Mkos1980

iTrader: (8)

LS1 !!! lol

tekkitan

iTrader: (1)

There are quite a few threads on 305 buildups in this forum. Search and read some of them they may give you ideas. Good luck.

sofakingdom

iTrader: (1)

Yeah we read that. Doesn't make it a good idea.

Then TALK HIM OUT OF IT. NOW. QUICK. Better now than to spend all his giga$$$ and then discover that it was A MISTAKE that he can't "take back".

He can spend $1500 rebuilding a 305 or 307, and at the end, have a 305 or a 307; OR, he can take THE SAME $1500 or whatever, and get MORE for it. Kind of like: he's got $10 in his pocket and wants a steak. So he goes to the grocery store and discovers that steak is $10 a pound. So, QUICK: how much steak does he get??? Does he look at it and go, ya know, I just want ¾ of a pound, so I'll spend my $10 and leave ¼ pound behind?? So why would it be GOOD to do that if it's a MOTOR?

Whatever he does, it's going to cost THE SAME. He might as well step up and get ALL HE CAN for his money. Which is NOT by rebuilding those "free" "paid for" "already has it" pieces of trash. That is the road to DISAPPOINTMENT.

We're trying to HELP you understand what SO MANY people around here have had to learn THE HARD WAY because they were too stubborn to listen to reason. Don't be just another hard-headed DUMBA$$ doomed to make the same mistake all over again. Failure to learn FOR FREE from OTHER PEOPLE'S mistakes is NOT a desirable character trait. That's the mark of a FOOL. Helo him make a wiser choice.

88fastgta

iTrader: (9)

my brother had a 92 camaro rs back in 08.... he built it up with a lunati cam (210-216 duration), headers and the usual boltons and still could not touch my back then stock l98 car with the only mod being a catback.. he was very upset with the results and kicked himself for ever doing it..it was his first car so i can understand why..but wasted about 1500 dollars. eventually he ended up selling the car because it just wasnt giving him the results he wanted.. the only thing i would do to a 305 is exhaust and thats about it.... heck i got a 350 block right now in my garage.... 50 bux and its yours...


sounded ok but wasnt really any faster...... actually because it sounded different from stock people would race him and he would get his *** handed to him everytime... quite embarrasing for a car to sound like that but be soooooo slow...

http://www.youtube.com/watch?v=Vm4GPCcAVe0

1gary

Sir,I give you all the respect and credit for how long you have been a member and your post counts.The O/P has said a number of times he wants to use the 305 or 307.Could you please apply all this time here to help him with that goal??. I suggest the 305 is a better choice.

five7kid

iTrader: (14)

The best choice would be to unload both the 305 and 307, and buy a 350 to build.

BUT, given the intransigence of the OP, the 307 shortblock with the 305 heads is the next best combo, assuming the 305 has 416 or 601 heads.

sofakingdom

iTrader: (1)

As detailed above, I can read. I know what he posted. I don't need your help.

I also know why what he posted, is A BAD IDEA, and the results of executing this BAD PLAN will not be pleasant. I will continue to try to talk sense into him because the thing he has said he wants to do is A BAD IDEA.

People come here for ADVICE, not for CHEERLEADING; and don't need to be helped down the primrose path to disappointment, WASTED MONEY, and regrets, by "well-intentioned" BAD advice.

I can take care of myself just fine without your misguided help.

If the OP simply cannot talk his less-experienced relative into a GOOD plan, then the one that five7 suggested is the LEAST BAD, assuming that the 305 heads he has are not "swirlies". If they are, then it will ALREADY cost him MORE to build a "decent" 30x motor, than to BUY and BUILD a 350, making it THAT MUCH WORSE of a plan. He would then be using EXTRA money as ammunition to shoot himself in the shorts.

InfernalVortex

iTrader: (4)

Instead of rebuilding a "free 305" or "free 307" block... if you're that hung up on 305s and 307s.... people give away perfectly good running 305's all the time.

I had a perfectly good running L03 that was high mileage, but didnt burn any oil, barely puffed at startup (couldn't even see oil smoke, just could smell it for a second), barely made enough power to wear out its own bearings at 170 fwhp.

I gave it away, because it was useless to me. Dont waste machineshop money on a 305. If you're bound and determined to just "Be different" with your 305 that 80 percent of all v8 thirdgens came with (who is being different, really?), then go get a free one someone swapped out of their car for a 350 or an LS1. Much better return on your money. Not as much as 350, but way better than sinking $700 into the proper machinework that nets you zero performance gain. Put that $700 into heads and cam for the free running 305 you just got.

86rs

Wow someone gets wat im saying. Like i said its not my car its my brother n laws and the motors are is dads the past away thats y he wants to use them its not a race car its goin to be a daily driver 10 miles to work car and maybe take to some shows. I think im goin to build the 307 with the 305 heads. Any body know wat the max lift is on a 305 head.

five7kid

iTrader: (14)

Find out which 305 heads they are first.

AlkyIROC

What's his logic to wanting to only build a 305 or 307?

More fuel efficient? Smaller displacement will burn less fuel but less HP means the engine has to work more to move the same weight.

Nostalgia? GM produced the 307 and it was a mistake but not their biggest one. The 265 V8 was worse. Just because they made those engines doesn't mean they're worth using.

Want to be different? Looking at a SBC under the hood and nobody will know or care that it's a small underpowered engine until they drive it.

Because he already has the engines? As I already mentioned, there are lots of free engines because nobody wants to waste money doing anything with them. If an engine runs, drop it in and enjoy it. If you have to invest money in a rebuild, just buy a new engine.

Just to be different? Lots of other weird engine choice to pick from if he wants something different. Even a 4.3 V6 would be a better choice than the 307.

sofakingdom

iTrader: (1)

Doesn't matter whether this Gary person tells you what YOU THINK you want to hear, or not; it remains A BAD IDEA.

Things change. The motor he puts in this "show car" (sounds like a hallucination to me - NOBODY wants to "see" a 307 or 305) might find some complete other purpose for it on down the road. What it actually CAN ACCOMPLISH might matter to someone over the age of about 8. (about as far as you can go before they figure out that putting baseball cards in the spokes of their bike doesn't make it work any better, and that just because it's "chrome" and "shiny", doesn't make it better either. First time they buy some Chinese piece of dung off of eBay they'll get a HEAVY dose of that. Although SOME adults never seem to figure those things out....) It'd be STUPID for him to limit himself to a POOR CHOICE that might bite him in the butt come that "other" day.

All of that "dad's" crap is worthless. Plenty of people when they pass from this world leave LOTS of garbage laying around. Just the fact that it was theirs for a brief time, doesn't change it from being GARBAGE into something worthwhile. If I had a dollar for every dumpster I've filled up with passed-away relatives' GARBAGE, I'd be a signifcant'y wealthier person now. Why I'd be able to buy a few beers or something, at least. You can be assured, that there is NOTHING left of that person's "aura" or whatever, hanging around their GARBAGE. Garbage is GARBAGE no matter whose it is. That's about the POOREST excuse for a motor choice that there is.

TALK HIM OUT OF IT. It's a screw-up. Whether it's what you, or he, wants to hear or not, IT'S A MISTAKE. He WILL regret it, and when he does, it will be TOO LATE because he will already have emptied his bank account on some turd.

TALK HIM OUT OF IT. Ignore Gary, he's part of the PROBLEM, not part of the SOLUTION.

Jim85IROC

iTrader: (2)

That's harsh dude. If his dad passed and he's trying to hold on to part of that memory by using the parts his dad left behind, who are you to try and talk him out of it? This obviously isn't about going fast or winning races... it's about keeping his dad's memory alive. It's a noble idea that I applaud.

That said, the first step is to find out what you've got. Look over both motors and see if they're both in equally good condition. If one has issues, your decision gets easier. Likewise, figure out what sets of heads you've got, and post them here so that folks can help you figure out what the best combination of parts are. The 307 is a larger bore, so I'd suggest going with that, as long as you can find affordable pistons. The odd bore size may make that a bit more expensive, I don't know. You could always use the 305 crank with the 307 block to get some extra cubes.

Don't forget that there's always the option of getting a stroker crank. For what it costs to get a stock crank turned, a cheap stroker crank will be an affordable alternative, will get you more cubic inches, but still allow you to use "dad's" motor. It might be a good solution. With the 307 block, it should get you around 340 or 345 cubes. Combine that with a set of vortec heads, and you might have a decent little motor.

86rs

Thanks man thats what we are goin for keepin his fathers memory alive. As for sofakingdom please quit postin on here ur doin nothin but wasting my time. Ill get with him and have him send me the numbers off the blocks and heads tomorow.

sofakingdom

iTrader: (1)

Sounds good to me. You don't want advice, you want a cheerleader, which I am NOT. I'm stuck in this thing called "reality", and just can't seem to get out. So if you want to go on in fantasy land (as I continue these many years to clean up the mess left behind by my many relatives both older and younger who have passed on and left their GARBAGE behind, which I continue to shovel into dumpsters, mixed in with their "treasures"), I'll leave you to it. Just, don't come back and say you weren't warned.

Jim85IROC

iTrader: (2)

He wants advice, just not yours. Everybody has a set of constraints that they want/need to work within. You offered your opinion that he should widen those constraints, but that's not what his goals are. His goals are pretty clear, and he's asking for advice on how to best handle the build within these constraints. It doesn't make it right or wrong, just different than how you think it should be done.

Awesome-X

I'm with the 350 crowd on this one. It would be more sensible to obtain a 350 block.
But the fact does remain that this is NOT the 350 crowds build, and he asked REPEATEDLY not to be harassed about their choice of a block. He specified the reason for their decision and that choice should be RESPECTED by this community. If you do not like said decision you can find your way out of HIS thread and move on with your lives.

You can make decent power from a 305 if you have the right head/cam combo and some good flowing exhaust. It all depends on how much you want to spend and what your overall power goals are.

86rs

I think im goin to stroke the 307 i think they said it comes out to a 330. I think it would be a neat little motor and how poeple can say they have a 330. I just got to figure out wat kind of crank goes in it to stroke it.

6998poncho

This is an OLD argument that goes back to the days before the 4th gen was the latest thing. I have experience with both and I'll tell you I'm on your side. I think most of the guys who say to get a 350 or a 383 want the fastest and the strongest SBC on the road. You can have a fine running 305 or 307 and enjoy driving it all the same. I had a 305 in my '89 Chevy pickup. After 30K miles it was discovered to have a factory defect (crack in the lifter valley) and a local dealer replaced the short block. I had continual problems because of shoddy work and eventually bought a 350 long block and did the swap myself about 18 yrs ago. That engine still runs great. Jason bought the 305 short block off me since it was essentially barely broken in and he needed it for a CMC car. I hope it served him well.
Anyway, I like the 307 because you can use heads with larger valves like a 350. The bore is big enough that you don't have the restrictions like the 305. Unfortunately, the 307 is supposed to use less nickel in the block and the bores may wear faster than a 305. That's was part of the discussion anyway. I was still able to get 135K out of my 307 before I had to rebuild it. It's a "smog" 283 that's stroked a bit. With the luck I had with 305's, my vote is for a 307.

6998poncho

You might want to stay with the 307 crank. To get 330 you need to go to a 350 crank. Then you might as well go to the 350. You might be able to swap the 305 crank in to the 307 block since I think both engines you have are equipped with the two-piece crank seal. Those are some options...

Irockz

iTrader: (1)

How about a cheaper,more productive solution?Buy the cheap 350 core that you are now well aware exists,make a 327.The "nostalgia" remains,because you've retained the crank and even the rods from the 307.
I strongly recomend you not bother with the small bore stroker,I've been down that road and can tell you that there is nothing there but a waste of time and money.If your hell bent to reuse a small bore block,use the crank you have,you won't be pleased with the "stroker" option.

youngz

just read this thread. the 305 is a good motor. 1990 camaros had the option for the 305 (LB9) 240 hp or the 305 (L03) at 170 hp. long runnin motors. 220,000 on my 305 LO3. it still has more than enough power. spins tires on dry pavement. the key to a long runnin motor is low compression or good parts or both. sofakingdom will probably call me an idiot for building a 302 chevy but they stay together. they were designed for race. the point is that its your money and your ideas. you have the ultimate say in the matter. sometimes less is more. built a couple 350s. your lucky to get 150,000 mi out of any one. my 305 will double that no doubt. tear it up and make memories out of it. thats the idea anyway right?

nascarfan7

The 307 is a 283 block with 3.875 bore 3.25 stroke crank from the 327. The 305 is a 265 block 3.735 bore and the 350's 3.48 stroke crank. Depending on the year of the 307 it may be a small journal block so any crank upgrades may need to be reground to those specs. Not sure if they ever got the larger journals when GM went larger in 1968 or so.

All sorts of pros and cons between the two but if I had to build one of the two, I'd go with the 305.

Then again you could drop a 400's 3.75 crank in the 307 and you'd have yourself the 350 everyone keeps saying to build, lol.

Jim85IROC

iTrader: (2)

307 with a 305 crank comes out to 328 inches. If you stick a 3.75" stroker crank in, you get 354". A standard .030 overbore on the 307 with the 3.75" stroke gets you 359 cubic inches. Not too shabby.

With the right heads, a stroked 307 could be a pretty good motor.

1gary

This is the last "free pass" you get.Understand??.The only thing I am new at is here.

Consider how many miles 305 have been driven.

If you look at this section,it says "engine swap". It doesn't say high "performance engine" swap or 350 only engine swap.

Customer has said over and over again what he wants and his relative told him to use the 305 or 307.Argument over.What about that do YOU not get??. His name on the title for the car.Right??.

My two cents worth is even through a 350 would be a better choice,a kinder-more helpful forum states it's opinion,then helps the O/P with what HE WANTS.It is for the betterment of the forum getting along with anyone.

I do not suggest the use of the 307 nor a stroker for the 305.

As you continue to rant,I think less and less of your opinion.I think at this juncture you now have two choices.Help him with his goals or move on.

tekkitan

iTrader: (1)

He asked for advice on 305 or 307, and clearly stated in his first post he doesn't want comments like "just buy a 350". I absolutely despise replies like yours and the sad thing is that I see them A LOT on these forums. If someone wants a 305, that is FINE. They don't need to have a 350 because you think it's better. Not everyone needs a 350, not everyone wants a 350. Get over it.

five7kid

iTrader: (14)

Alright, just for kicks, I did a little research on 3.875" bore pistons. They are readily available in .020" and .030" overbore sizes, with 3.25" (stock) stroke, for a reasonable price. Basically nothing else is available. If you put a longer stroke crank in it, you're talking custom pistons and BIG $'s.

305 stroker kits are more common, but I still wouldn't advise that.

For the sake of legacy, I'll continue with my advice. Obviously this build is based on emotions and not HP/$, so stick with a "stock" rebuild. Whatever short block you decide to use, just reuse the crank that is with it. A 307 with a nice cam, 305 heads of the casting #'s I stated above, good exhaust, and a simple carb, will be just fine, and he'll have his dad's engine living on.

Oh, another reason to use 305 heads is 307 heads didn't have hardened exhaust valves & seats for unleaded gasoline.

(For the record, all 307's had large journal cranks.)

stroken85z

I have heard of a destroked 307 whats the deal with that setup

affliction1

i will admit my 305 is a pretty quick one and does give 350s a run for there money but it wouldnt hurt me a bit if someone drained all the oil out of it when i was sleeping,so i could crank it up, burn it up,trash it,and buy a 350 lol.ive been dogggin it every day for like 8 months and it wont blow up lol so...it has the reliability factor in my book,just prayin it will blow.eventualy......oil preasure is still great,runs 180 degree all day long and gets 30mpg if im easy on it.

affliction1

shorter rod throws,engine will revvvvv to the moon

gwarren007

iTrader: (1)

Combine them both assumming they are both 2pc rear main seal-

machine the 307 block .030 over (3.905)
have the 305 crank polished/turned
Source a set of 4.3L V8 (L99 engine) rods
get a set of LS pistons
(998383.905 3.622 6.098 9.000 1.326 -4.000 0.945 $699) from flatlander racing or a lower cost one with the same compression heght.
http://www.flatlanderracing.com/index.html


That will give you a 9.006 Zero deck height. Grab a set of vortecs and have fun...


1.331 compression height will give you 9.011 height, and Ebay has pistons for ~300.
http://cgi.ebay.com/ebaymotors/1997-...item415bc094a7

InfernalVortex

iTrader: (4)

This again?

Stroke has VERY little to do with revving capability. That's all about having a bottom end that's strong enough to hold it together and a top end that's built for high RPM power. The reason the 302 sbc revved so high was because of its massive solid lifter cam shaft and valvetrain/rotating assembly that could handle it.

A destroked 307 is, as has been mentioned, just a 283.

If shorter strokes were the bee's knees, no one would be building 383s.

affliction1

yes you will lose compression and power
Put a 267 Chevy crank in a 350 (or is it a 400) block and get a 5 liter, 8,000 rpm screamer.

1gary

I'll try not to get too off topic with this brief comment.Back in the day we used to destroke small journal 327's with 283 cranks to a size of 301's.Then mount the biggest Mondello head we could,tunnel ram,solid roller lifter cam,aluminum rod,and the highest compression dome piston that would fit.That was a formula for a say B/MP drag race car.We would certainly buzz that up to the moon.Why??. It is all we knew and Smokey wrote that was the hot set-up.We now know soooo much more and the cam,induction,head,computer tech,has developed so much more,let alone materials we now have that wasn't around then.

torque_is_good

Don't forget the guys who tried to hide weights in their cars so they could run C modified

my brother destroked a 340 Mopar. We have come a long way.

1gary

I knew a guy the spent god knows how much to 3/4's the way fill the rear frame rails with Mercury.When the car launched the Mercury would slosh to the back of the car with a huge wheel stand.Hehe-he got caught and NHRA ban him for life.