Decided to take on some opinions on my build. Keep in mind this is a manual transmission car. Try to keep all the 350/383 to a minimum, looking for something that doesn't require tight oil control for a daily driver (for the most part).

Roller Cam / 1 Piece RMS 302

1989 350 4-Bolt Main (1 Piece RMS)
Standard bore (Didn't NEED an overbore)
L99 Crankshaft (3" stroke 1 Piece RMS)
L99 Rods ( 5.940" Length)
KB 10.4:1 CR Flat Top Pistons (2 VR)

Vortec Heads
Set-up already to handle .550" lift
Set-up already with cleaned up CC and ported Intake runners

Using a Comp Cams Magnum Hydr. Roler
P/N - CS 280H-R10
Dur @ .050 - 224/224
Adv Dur - 280/280
Lift @ 1.5 Rocker - .525"/.525"
Lobe Sep - 110

Using my existing Edelbrock RPM Vortec Intake
Using my existing 1.5:1 Summit Roller Rockers
Using my existing Holley 670cfm Street Avenger Carb

I've already got the Posi and 3.73:1 Gears in my 10-bolt. Already have the SLP 1 3/4" headers, still running the stock cats, and stock pipes with a flowmaster muffler. (Debating on swapping in the Gale Banks system).

Just looking for some opinions on what you guys think, some of you have great knowledge of motors and such. Doubt this would go to the track much, not really interested in Drag racing, not far enough along to worry about those things.

Should have most of my parts in within the next 3 weeks and begin the assembly. Trying to start the swap over Thanksgiving break, unless the 305 grenades before then.


Sorry for the insanely long post, hate to abbreviate too much and leave people puzzled. Must be obvious that I'm a newbie.


-Ryan

BTW : Should figure out the whole signature and posting pics sooner or later.

 

Sounds good, but that might be a little much cam for a daily driven 302.

 

very close to 69 Z28 dz302 specs. Your car ought to run high 12's until you dial in the chassis. Good choice of stuff.

 

Thanks guys, its always nice to see that there are positive thinkers.
I noticed that quite a few of the threads get destroyed by disrespect and bad attitudes.

Air_Adam - You think the LT4 Hot Cam might be a better choice?

KrisW - I was never really into drag racing (car was always too slow), was always more an Auto-X fan.
Yet to Try that though.


I've always admired the DZ302 Cars, as well as the less known "MO" Code 302s.
Its not too often we even hear about the chevy 302s, especially in a 3rd Gen.
Figure this setup is an excuse to buy a bigger hood.

 

Didn't you Know?? TRANS AM racing is the reason the DZ302 was invented!! Chevy had to field a 5.0 liter engine and be able to road race like crazy.350 block + 283 crank = big bore/short stroke high rpm 302!!

 

I don't know the stock specs of the LT4 cam off hand. Your right though, that is a similar cam to the old DZ 302 motors. But thats why I said that it would probably not be a good choice for a daily driver.

Back when the DZ engines were built with cams like that, those engines were barely driveable on the street. They got terrible mileage and they were absolute dogs at any kind of sensible rpms (ie. below 4000) and they got worse gas mileage than a 426 hemi. And the hemi was 2L bigger and had 2 carbs. Thats a HUGE cam for an engine that size.

I'd go for something more like around .450 to .480 lift and maybe just a little less intake duration and a little more exhaust duration than the cam you spec'd in your first post. Vortec heads like having lots of exhaust duration.

An engine like that will really like a carb with mechanical secondaries too, like a 600 or 650 cfm double pumper, Especially if you are gonna run a manual trans (you didnt say if you are using auto or manual).

 

Best streetable sbc cam I ever ran was a summit ripoff of the edelbrock rpm cam. .488/.510 224/234@.050 GREAT POWER and I could still drive it to get the groceries!! Lots of street fun. RPM intake 750 Carter 9000 and 1 5/8 headers. high 12's. SOME FUN!!!

 

Hey, I like options.

Can always step up to a 4.11 gear, being that this car is a 5-speed.
I've yet to order a cam for it, so its nice to see some additional options on the table.
Since I've already got the 670 cfm Holley, no real need for a different carb, yet. (Have to try this one)

As far as a cam goes, I'll keep looking around.
Just would like to keep it a Hydra Roller, which is the reason I didn't just use an old 327 with 283 crankshaft.

So its basically the cam (one of the few things left to buy), thats causing the most trouble.

What would you think of this:
Dur @ .050 - 218/224
Adv Dur - 270/276
Lift @ 1.5 Rocker - .495/.502
Love Sep - 110
This is a Comp Cams Xtreme Energy Roller Cam


Once again, thanks for the input.

 

not enough carb for this cam. When you're picking cams, you need to take into account bore and stroke. A 5.0 liter 302 with a 4 inch piston needs a similar cam to a 350 or 327 with similar carb requirements, whereas a 5.0 liter 305 with a 3.736 piston needs a similar cam to a 283 or 307 with 3.875 piston with similar carb requirements. Fine tuning will vary, but your engine will loosely follow a 350's requirements due to the larger bore.

 

Well then, guess its time to either take the 750cfm Edelbrock off the shelf or buy a bigger Holley.
Hell, even new Holleys run about $400, about the same price as a TPI Throttle Body.
Either way, its an easy fix.
Can swap carbs in under 30 minutes, cams are another story.

Just glad to get the right feedback, good thing to push around some ideas.
Not great with this type of setup, usually stuck with the TPI.

 

I ran a 750 Carter AFB (same as edelbrock) with outstanding results. I think you'll find it more than adequate. You may have to re-jet and tune the rods a little to get it perfect. Mine was spot-on right out of the box.

 

For that engine to be a stout street engine, you will want a cam thats under .500 lift. With that bore and stroke, horsepower isn't hard to make, because its a very good BxS for good breathing. Its low end torque that will be a challenge.

Thats why I suggested a smaller cam, so it will have some low end grunt. If you can find the specs for a 1973 Z28 cam (its the L82 motor) then that would actually be a very good cam to use in a engine like that, or at least something similar.

I dont remember the exact specs, but it was about .460/.480 lift and about 215/220 duration. Something like that anyway, like I said, i dont remember exactly, but something about that size would be great for a 302.

 

Found the L82 cam specs. Something similar to this, maybe slightly bigger, would be just right for your engine.

Cam specs: Hydraulic, Lift: .450/.460 (intake/exhaust), Duration: 346/360 (i/e), with 1.5 rockers.

(taken from nastyz28.com)

 

Actually, probably the best cam for that 302 is a XE268.

.477"/.480" and 224*/230* @ .050

Perfect cam for your combo IMO. Stekman might tell you the same thing (right mike?)

 

The XE268 might work better with the 3.73 gears I already have.
Thanks for the help man, I'm the worst person to choose a cam.

Looks like I'm pretty much set on the motor now, more or less.
I'm just glad to have found some actual good help with a cam selection.
I can figure just about everything else out, just them cams are tricky.

 

Forget the SA, Performer, AFB, q-jet type carbs.

A 650 Holley or Demon double pumper is the way to go.

Bigger will only promote bog, and won't feed it any better.

 

Well, my luck had to run out eventually.
No DPs on the rack here, looks like it goes on the hit list now.
Any other ideas or things I may have overlooked?

I think this will be really hard to disguise as an L69 soon.

 

Get the right air cleaner and steel valve covers, and you shouldn't have a problem.

That air cleaner is HUGE... it can hide alot, lol.

 

Cam Vote:

Don't go with less lift...Always MORE lift with a roller cam and plan duration accordingly.

If your heads are set up for .550 lift, then go with something like the LT4 HOT cam...lift around .525 or .535 (just to make sure you don't max out the springs) and duration 218@.500 for intake and 225@.500 for exhaust with LSA of 112 for slightly better idle vacuum.

Don't go with an off the shelf cam unless you can find one with similar specs to above.

 

that is basically the hot cam, you described.

you could also go with the CC305 cam, very similar to hot cam.

 

I just got an LT4 HOT Cam, traded a 91-92 Firebird Nose and Fender GFX.

Anyone have any opinions on a TPI versus Carb on this?
Offered a MAF Setup for my 85-90 Trans Am GFX conversion, would it be worth the swap?

If I'm not flooded out this weekend, should be assembling the short block

 

CARB!!!

Go nowhere near TPI for this!!

Get yourself a Holley 650 double pumper and a Perf RPM manifold... it will be WAY better than TPI could ever be.

TPI is restrictive on a 305. Thats basically the same motor you are building (size-wise) so why create a restriction? Plus, all the other parts you are using will make this 302 a top-end power engine, not a stump puller. That just doesn't work with a TPI setup.

 

Should have known better.
Was a question worth asking, already knew the answer.

Guess its a Newbie thing, bass ackwards.

 

No sweat... 2nd opinion never hurts, right?

 

I had to ask.
Just would suck to finish the motor and find out it would have run 10x better as a TPI car.
Would be my luck, trying to make the best out of what I have.

For the 10 Millionth time - Thanks

 

Sounds like a good project man, keep us updated!

 

That's the easy part.
Now all the work, thats another story.