92RS_Ttop

iTrader: (3)

I want to swap out my 3.1 V6 engine for a V8 and got a block and 3 sets of heads from a friend who didn't need them. I'm just not sure which set of heads to use on the build. I have been reading through the posts on here, and I still haven't been able to decide. I need to do this as cheaply and easily as possible due to an extremely tight budget. All the heads are in usable shape, they just need cleaned up. I'm not looking to make a 10 second car, but I would like to get around 300-350 in HP and torque. Its not gonna see the strip(can't run with shaved door handles in PA I've been told), but I do wanna be able to tear up the backroads around here and be able to beat on all the stupid ricers around here with the 10 second wings and weedeater mufflers.

The block casting number is 3970010 and the stamping is 11y134372k0527cgc by the passenger cylinder head. I've read that it was originally from a 71 El Camino or Police Package car making 245hp.

The heads I have to choose from are:

333882 - supposedly the heads that came with the engine, at least when my friend got it. I've found they are 76cc, 1.94 intake/1.5 exhaust from a 350.

462624 3898891 -Set of mismatched 350 heads he had laying around that he just threw in to get rid of them(he's in the middle of moving). Supposedly same specs as the 333882's.

14014416 - Set of heads from a 305 he tore down a while back. I've found they have 1.84 intake/1.5 exhaust, 58cc.

I've read on here that of those 3 sets, the 305 heads seem to be favored, but I've got a few other worries about using them.


1. Is the compression ratio I will end up with going to be manageable? I'd rather not run 91 or 92 octane, as I said, money is tight but I can if necessary.

2. Yes, I do plan on porting/polishing them, but can I take the 1.94 intake valves from one set of 350 heads and use them in the 305's as long as they are machined for it?

3. The engine block does not have a cam, lifters, or rocker arms. Can I use the rocker arms and springs off of one of the 350 heads?

4. Cam recommendations??

5. I'm not sure if it makes a difference or not, but the intake I have appears to be a dual plane design, casting # on it is 14014434. Will this intake bolt up to the 305 heads if I use them?

Please don't tell me to buy vortec heads or scrap everything and buy a complete engine. I'm trying to do this as cheap as I can, still get decent performance, and learn a little something in the mix.

Thanks for any and all advice.

92RS_Ttop

iTrader: (3)

Some things I forgot to mention that might prove useful. I will be running these with a carb, the valve covers I have are perimeter bolts(99% sure of this), the block has good flattop pistons with the valve reliefs, and the car has the stock rear end in it which I believe is a 3.42 from the info I was able to find on here. Oh, I almost forgot, I have to pass a visual emissions check here.

92RS_Ttop

iTrader: (3)

Anybody?

Pat Hall

iTrader: (31)

It depends quite a bit on which pistons you have. If you're running a dish style factory piston, I'd say to use the 305 heads and have the larger valves installed in them. Maybe pick up a deluxe porting kit from Standard Abrasives and so some porting while you're at it. If you have flat top pistons in there, you'd be better off using the 882's, since you'd end up with a pretty insane CR for pump gas with the 416's and flat top pistons. From what I've heard, the 624 are total boat anchors. The 624 and 882 are both lightweight castings, but the 624's are way more prone to cracking. You could also ask the machine shop how much they think they could safely mill off the 882's to bump up the CR a bit more if you're going to run them with flat tops. With a 76 cc chamber, the CR will be pretty low, even with a flat top piston.

92RS_Ttop

iTrader: (3)

I was kicking around the idea of having the machine shop mill off some of the head on the 882's, but I'm not sure how much. I do plan on porting them, probably with the Standard Abrasives kit, or something similar.

The pistons are flattop pistons, they have 4 valve reliefs cut in them.

I was told the heads were good by the guy I got them from, and I trust his judgement, but I'll double check them once I get them cleaned since they were in storage for a couple years.

One of my main concerns was how to lower the compression ratio if I were to use the 416 heads.

Pat Hall

iTrader: (31)

If you used the GM Performance head gasket #12557236, which is .051 thick, it comes up as 10.0:1 with the 58 cc heads. I typed in +7 cc for the piston head volume, since that's about average for the 4 VR flat tops, and this is also assuming the block hasn't been zero decked (i.e. pistons are about .025 in the holes). If it's been zero decked, it comes to a whopping 10.6:1. Here's a link to the online calculator I used. It's come in quite handy for me recently as I've also been trying to tailor the CR on a new engine I'm working on.
http://kb-silvolite.com/calc.php?action=comp

92RS_Ttop

iTrader: (3)

As near as I can remember it hasn't been decked at all. I will measure it for sure tonight after work. I was actually hoping to stay out of the range where I would have to run 91 or 92 octane, I was thinking around 9.5:1 would be safe for 89 or even 87 octane. Am I wrong in thinking this? Also, the cam I was thinking of using is Sum-K1101 or the Sum-K1105. Would this combo work out ok?

Pat Hall

iTrader: (31)

I have to agree with you on keeping the CR at 9.5 or lower if you want to run the low octane fuel, especially with cast iron heads. I'm run the mid-grade stuff in my 69 Camaro with about 10:1 and cast iron heads without any detonation problems, but I'm also at 5,000 ft. above sea level where I live, which helps you get away with lower octane/higher CR's. Out of the two cams you posted, I'd definitely go with the K1105. The 1101 is way too puny. In fact, it's probably really close or identical to a low power, factory cam. If you wanted a little more low end grunt, the 1104 would be a good choice. In fact, it'd probably be a better choice than the 1105, given the limited flow capability of the factory heads, even when ported. If your budget limits you to using a Summit cam, go with the 1104 or 1105. Of course, if you can afford to spend a little more, there's much better cams out there. The Comp 280 Magnum is a really nice cam for your goals. Then there's also the Lunati Voodoo series, which are supposed to have the latest innovations in flat tappet cam design. Try to stick with 280 adv. duration or less, .500 gross lift or less, and a LSA of 110 degrees or higher. If you pick a cam similar to those specs, along with 3.42 or lower rearend gears, you should be able to easily thrash on those imports who think they're fast. With a dual plane intake, that range of cams should give you enough low end to take off from lights, and have an excellent mid range power band. P.S. I was just looking at the Voodoo cams on Summit's site. LUN-60103LK, along with some Comp 981 springs would be a sweet combo. Even better would be to buy just the cam, and run a set of Crane or Rhoads variable duration lifters. I use the Crane variable duration lifters in my motor. They improve the low end power and vacuum when you're running a larger cam without sacrificing the top end power. The 60102 would be good too, if you wanted something a bit tamer. Any cam over .480 lift should be run with upgraded valve springs. Scoggin-Dickey has the Z/28 HD springs for cheaper than the Comp 981's. If you're running an auto trans, a 2400 or higher stall converter would be highly recommended to take full advantage of any of the cams listed above.

1989GTATransAm

iTrader: (3)

I agree with the Voodoo cams. One of the best flat tappet cams out there. I agree with what Pat has said. Well maybe the +7 on the 4 relief valve pistons. I think they coukl be a tad more than that depending on what factory version you have.

92RS_Ttop

iTrader: (3)

When you say ".500 gross lift or less" do you mean seat-to-seat timing vs. .050 timing, or lift at the lifter vs. lift at the valve?

Will the stock rocker arms be ok to use with these cams, or will I have to replace them with aftermarket?

Also, do you know of any calcuators/programs that will give me an idea of what kind of horsepower/torque numbers to expect from different combinations? I have been using a program called Desktop Dyno, but I'm not sure how accurate it is. I got almost the exact same results using the SUM-K1105 vs. LUN-60103LK. And the numbers I got for the K1105 and K1101 were close too. The results I got are below, do these seem about right?

Lunati LUN-60103LK: 375HP@6000 and 378lb/ft@4500
Lunati LUN-60102LK: 370@5500 and 386@4500

Summit K1105: 371@6000 and 379@4500
Summit K1101: 324@5000 and 398@3000
Summit K1104: 362@5500 and 379@4500

Sorry for asking so many basic, dumb questions, but I've never really gotten into this until now and I don't want to put together a combo that I won't like, or worse yet, will not work together at all.

Pat Hall

iTrader: (31)

Those estimates look to be fairly accurate. Lots of guys use the Desktop Dyno program, and it's usually pretty close. .500 gross lift is the advertised lift, or in other words from 0 degrees duration to fully open. Once you get in the neighborhood of .470 to .480 gross lift, you have to make sure you're going to have enough clearance between the underside of the valve spring retainer and the top of the valve guide in the head. If you stay at .470 lift or less, the only thing you really need to do is get the valve springs that are recommended for the cam you pick. Your stock rocker arms will work just fine. Roller tipped or full roller rockers are always a nice upgrade, but they're not a necessity. Another concern when you start running cams with more than about .480 lift is the pressed-in rocker studs the factory uses. They can pull out with a high lift cam, so you have to get screw-in studs installed. Once you exceed .500 lift, I'd say screw-in studs are mandatory.

92RS_Ttop

iTrader: (3)

Sounds like I will go with the 1104 then. I'm not looking for a ton of power right now, I just want to get it back together and in the car. Once I get that done, I can always upgrade the rocker arms to rollers later. I think I'm going to have the rocker studs changed over to screw-ins now though, just to be on the safe side. I was considering having it done anyhow, so I might as well do it. Is that something that the machine shop has to do, or can it be done with a regular tap and die set?

I just had one last question, if you don't mind answering what should be a fairly obvious one. I'll probably use the factory rocker arms for now since I have a good set, if I wanted to change the lift on the valves at a later date all I would need to do is change to a 1.6 rocker and/or a longer pushrod, right? And different valve springs if necessary of course. I'm assuming this will work, but just wanted to make sure.

Thank you for answering all of my questions, even though they are probably pretty dumb ones.

djtricia

iTrader: (4)

Questions aren't dumb. Some people an get an education just reading what the responses are to your questions. Keep asking them. And here's one: What about just putting 1.6 on the intake or exhaust valve side only?

89RsPower!

the only thing that hasn't been addressed yet is passing a visual... so that means you would need the complete AIR system EGR etc, also you won't be able to run a carb and pass a visual if this car is a 92.. also what are you going to run for a trans? the v6 tranny isnt gonna bolt up..

92RS_Ttop

iTrader: (3)

According to the guy I take my other cars to for inspection, it will pass as long as it has all the emission stuff bolted up to it. Also, PA is weird about the visual emissions inspection. If a car is driven less than 5k miles/year, it does not have to pass a visual inspection. The only catch is that it has to be titled in my name for a year beforehand.

Now that I think about it, I may have to get a new intake manifold though. I can't remember if the one I have has an EGR port on it or not. I don't see why I couldn't bolt one up to the existing manifold though. It will be under the air cleaner and the emissions equipment doesn't have to be working(no sniffer test), it just has to be present.

As far as bolting up the V6 tranny to the V8, it can be done. The bellhousing needs swapped to a bellhousing off of a V8. The stock clutch, pressure plate, and flywheel from my V6 will need to be replaced. From my research on this, a normal 153-tooth flywheel will work, and a clutch disc from I think it's an 85, 86, or 87 S10 will work. Its a 10.5" 14 spline clutch disc. I haven't looked for a pressure plate yet, I'm assuming a stock V8 one will work. I don't have the $$ right now to replace the tranny, and I wouldn't want pay to upgrade to a T56 anyhow, I don't do enough highway driving to justify a 6th gear. This isn't going to be a highway cruiser, it's going to be a back-road-slide-the-***-end-around-curves driver, with the occasional beating on all the damn ricers around here.

89RS, I'm not sure what you mean about not passing the visual? Even the early thirdgens with carbs had all the same emissions equipment bolted on to them. AFAIK the AIR, EGR, etc is the same, just mounted differently between carb and FI engines. Worst case, I should just have to buy new brackets and a new belt(s).

92RS_Ttop

iTrader: (3)

*** is blocked, but damn isn't???? WTF???