Jadyn Miller

Is this too simple?


I wanted to post my budget build for a STREET drivable old 350 with Vortec Heads and see what y'all think and what I forgot.

I have:

-A stock 4 bolt main

-906 or 062 headsVortec manifold

I ordered:

-COMP Cams CL12-238-2 - COMP Cams Xtreme Energy Cam and Lifter Kit

-Timing Set

-Seal Kit

-Head Bolts

-Cam Lube


And that should be all I need, right?
Or am I totally f'ing up?


I was planning on reusing stock pushrods.
Never done a cam either so if there's any tips. I'd greatly appreciate them.

Komet

How are you delivering fuel?

sofakingdom

iTrader: (1)

Intake, carb or EFI, exhaust, gears, transmission, car, car weight, converter, PURPOSE OF CAR, prior experience level, ... ???

That's a flat-tappet cam. Why not a roller? Why would you enter into the realm of obligatory self-flagellation?

Next time, try, "I'm thinking about ordering ...", BEFORE you click "buy it now".

midias

For push rods you will have to measure.
What are you doing for rockers? Self aligning or getting the heads machined for screw in studs and guide plates?
What springs are you using? I would upgrade for sure.
What machine work did you do to the heads magnaflux or check for cracks?

I would skip the 4 bolt if it is flat tappet style and find a more modern roller block.

Jadyn Miller

Like I said boys, budget build. I plan on using the quadrajet and stock rockers until I have more moola. Was hoping I could use stock springs and rods. know it's skimpy, but I just want something to show off and still be tame enough for regular driving.
​​​​​​I have a turbo 350 and not sure of the gears, but I know they're low because I run about 3000 at 65. It's an 85 firebird. Also got shorty headers.

Just wanna make sure my skimpyness isn't gonna make for an engine that'll just blow.

Jadyn Miller

Thanks for the replys. Here's some more info.

Wanna use the quadrajet until I can upgrade, same with rockers, springs, and rods.

Has a 350 trans. Not sure what gears but I know they're not stock because I run about 3000 rpm at 65.

Got some shorty headers.

And yeah...I know it's a skimpy build. I wish I could do more like you guys recommend but money's tight.

So I guess what I really wanna know is if this thing will just fall apart if I go with the stock stuff and the parts?

Thanks y'all

Komet

Looks like you're going to run into valvetrain geometry trouble. The stock vortec heads won't be able to take that much lift from the cam, so you're going to at least need valve springs and potentially pushrods depending on how things measure out. Check out:

https://www.streetmusclemag.com/tech...benchtop-mods/

I recommend reading up on what people commonly do machining-wise to vortec heads when also running a hotter cam than stock.

midias

Are your stock rockers self aligning? If not you are going to have a lot of issues using vortec heads without guide plates. If you are running guide plates get better pushrods
The stock quadrajet is a fine carburetor are you planning on staying computer controlled?
If they are Flowtek shorty headers return them and get something better. Buy once cry once don't buy twice.
I would not use stock springs terrible plan look at the link above
with a turbo 350 trans I would worry about what other items were butchered by the previous owner

y5e06

if you have parts and you are on a tight budget: use what you have! its better to be driving around than dead in the driveway.
votecs & intake, stamped steel stock self aligning rockers, flat tappets, new pushrods IF needed, etc. you can reuse stock head bolts or go with a less expensive (summit...) cam.
go ahead and put in a new oil pump & pickup. 3/4" pickup version if you can swing it.
your cam has
Intake Valve Lift with Factory Rocker Arm Ratio: 0.462 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.469 in.
so you might get away w/ the stock rocker studs and perhaps ls6 springs & Comp 787-16 for that cam without any machine work.

Jadyn Miller

Thanks guys.

So it sounds like valve springs and pushrods and it'll be possible. As a rookie I don't really know what these guidplates you speak of are. Do you think you could tell me what to get?

y5e06

with vortecs you don't need guide plates. you can use the vortec's original stamped steel rocker arms which are self aligning. This negatess the need for guide plates which locate the push rods. also you'd need screw in rocker studs with guide plates anyway.

Komet

Also check out this dude, he has some videos on vortec heads as well:

y5e06

https://www.youtube.com/channel/UClr..._imvwcQ/videos
this guy has alot of good vortec info too

skinny z

Let me relate my 1st Vortec 350 build (but it wasn't my first build).
350 block from the 70's. Bought it as a complete engine that was 20 years old but never run.
New Vortec heads and used as they came from GM complete with the whimpy factory springs.
Flat tappet Comp 268H cam.
Added an Air Gap intake and Holley 600 vacuum secondary carb.
Plain HEI distributor.
Edelbrock shorty headers and y-pipe.

That cam had a .454" lift and there was sufficient clearance to the retainer and valve stem seal.
Took the usual precautions with cam break-in and used either Rotella diesel engine oil (although I've heard that isn't necessarily the best thing for a gasoline engine). Alternately, I added a bottle of GM's engine oil supplement to a quality synthetic oil.
Assembly was easy and straightforward. I wasn't too dialed in on valve train geometry at that time and used the original push rods because that's what I had. That said, the Vortec cast iron guides are extremely durable so any poor geometry doesn't necessarily show up as wiped out valve guides.

There are a couple of things to look out for. Examine closely the clearances in the valvetrain during a full cycle. Your cam choice is pushing the limits of the heads. If there IS an issue, there are options available that require no machining via springs and retainers.
Another is the risk you take with flat tappets. Despite the best efforts you're fighting an uphill battle on a couple of fronts. The first is today's engine oil formula. It's not what it used to be. Especially the everyday off the shelf Walmart special. Research what the racers are using in their flat tappet engines. Speed Talk's Engine forum is a great source for that info.
The second is the quality of today's FT lifters. Again, check out Speed Talk for who is using what.

If anything, the only thing I would consider is the move to a roller cam. You'll save potential headaches. FWIW, the cam I mentioned in my build DID go flat eventually and took every machined surface in the engine out with it. The stock springs were OK up to the engines peak HP plus some which arguably was 5500 RPM. A missed shift wound it out to well past 6K. That meant replacing a bent valve. Might have been two.

So your build direction is doable but there are some caveats to be aware of.

Jadyn Miller

So after digging into the engine I ended up adding new cam bearings, rod bearings, rings, high volume oil pump, soft plugs, and pushrods.


My head's didn't come with rocker arms so now my only question is:

Can I use the rocker arms off the old heads?

F-BIRD'88

Unless you add guide plates to the vortec heads you need a set of 87 up guided style rockers.
Best to buy the long slot version..
Spring retainer to guide boss seal must be checked for lift clearance.
The stock springs will not work with that xe cam.

The gm LS6 spring with comp 787-16 retainders seems to work well.. Summit has their house brand copy of the LS6 springs now.

F-BIRD'88

You need a vortec style intake manifold.
The older sbc intakes will not fit nor work on vortec heads. Lots of choices.. A carb adapter allows q jet carb on 4150 square bore flange intakes.
Eg Weiand 8121
That cam likes a diz modified mech advance curve.
Limit the mech advance to 12-14 degrees travel stop limit.. This allows more idle base timing.
20-22 base initial 34-36 deg max advance.

Fast355

iTrader: (2)

Fast burn style chambers do not need that much timing. My 11:1 383 likes 16° initial, 15° mechanical (get the right weights and center section rather than using a stop or welding the slots) and mine has 15° vacuum advance. Total timing is fully in at 3,600 and the mechanical advance starts at 1,500. Vacuum advance canister is on manifold vacuum and starts to advance at 7 in/hg and fully in by 12 in/hg. At 3,600 rpm with no load my total timing is 46° and it runs smooth as silk.

Modified 850 cfm Q-Jet is the only carb to run in my opinon. Especially if you want decent driveability around town and good fuel mileage. See my post in the carb board for details on this one.

I actually wish Edelbrock made their performer rpm q-jet vortec manifold without the stupid expensive brass marine liner in the coolant passageways. Since my heads are dual drilled, have an EPS on mine with an adapter.

NoEmissions84TA

iTrader: (1)

Look at you with that nice aluminum plate to adapt your engine stand to the block's bellhousing pattern. You made that, right?

I actually wish Edelbrock made their performer rpm q-jet vortec manifold without the stupid expensive brass marine liner in the coolant passageways. Since my heads are dual drilled, have an EPS on mine with an adapter.
Wait a minute - your heads are dual drilled? So then you could bolt on a 7104 Performer RPM Q-JET, correct? Would the ports align?
I might have something for you...……… Here is something I found in the meantime:
https://www.ebay.com/itm/Edelbrock-P...EAAOSwgltgchqc

Fast355

iTrader: (2)

ICT made the billet adaper and it is solid.

The assault heads come dual drilled.




Ports line up pretty well with both the Vortec and traditional intakes since they are a good bit larger than the manifold ports. I can get the 7104 for about that at work, same day from our Dallas warehouse. Just dragging my feet. I literally cannot decide which to run Q-Jet or Vortec EFI.

skinny z

You're talking HEI correct?
Care to elaborate on how you managed to restrict the mechanical advance to 15°? While I haven't used an HEI in years, I'll be substituting one in place of my MSD setup when (if?) this new engine goes together. And much like the curve you've described, I'll be close to 20° initial and about 14° mechanical. The only method I've found, in either aftermarket or OE, is to weld up the advance slot and trim it to suit. As opposed to the advance bushings with the MSD.

NoEmissions84TA

iTrader: (1)

When the EMP pulse hits, the quadrajet will continue to work. That fuel injection system will be fried.

Are any other brands of heads dual-drilled for both intake patterns besides Assault? That is a great feature.

skinny z

My now ancient (discontinued about 10 years now) RHS Pro Torkers have a dual pattern.

Fast355

iTrader: (2)

Yes I am talking about HEI. I have probably 50 different used center plates and weights that I have robbed out of junkyard GM vehicles over the years. Different weights and center plates give different advance curves and total advance amounts. My combination is a 363 center and 053 weights.

There has a chart of many combinations tested.

https://www.crankshaftcoalition.com/...EI_distributor

Mortorq

Noemission84TA-
“When the EMP pulse hits, the quadrajet will continue to work. That fuel injection system will be fried.”

Haha! Good one! We won’t need carbs either. The U.S. will be PERMANENTLY back to the colonial days!

I have a welded slot in my HEI to limit the advance.

Fast355

iTrader: (2)

Problem with welding the slots is that it changes the shape or curve of the advance curve. The center section and weight combination alter the actual curve as much as the springs do if not more.

Where one weight/center section gives something like. (363center/053weights)
1,000 rpm = 0 advance
1,500 rpm = 1 advance
2,000 rpm = 8 advance
3,600 rpm = 15 advance

Another combination may give
(369 center/41weights)
1,000 rpm = 2 advance
1,500 rpm = 15 advance
2,000 rpm = 18 advance
3,200 rpm = 22 advance

The above values are actually values I noted using the same advance springs even. Just different weights and center sections. If you merely welded the slots to limit the advance to 15° on that 369/41 weight combination you would get your full advance curve in 1,500 rpm. Given the ~2,000 rpm difference between where the advance comes in, I doubt even stock springs would prevent you from having too much advance too quickly.

Give me a magneto and some corn and I will make some Ethanol to feed my carb and maybe myseld, lol.

NoEmissions84TA

iTrader: (1)

Yep - magneto, carb, and moonshine and you are still on the road.

Black 84 Z

Is there any source to buy different weight and center sections? Same as the poster above I'd like to limit the advance to about 14 and don't have the ability to weld the slot. I've looked at curve kits but most of them still have too much advance and can only change how quickly it comes in, not the total.
​​​​

Fast355

iTrader: (2)

My source 15-20 years ago was the junkyard, not sure where you would find them now days. Carbureted GM cars and trucks were super common there at that time.