Hi, first post,

I recently purchased a 1985 IROC-Z equipped with a 305 and manual t-5 transmission.

Some work has been done on the engine (intake manifold, headers and, carb, maybe more) and the body (chassis hardening bar, lowered suspention and drilled discs brakes on all wheels). I changed the radiator for a 3 core and added two electrical fans. Cylinders head are stock.

So I want to upgrade the engine. I know relatively little about overhaul, so feel free to tell me if I say something idiotic, I'm still learning

I want to change the cam and heads. I was considering Edelborck's 64 cc i 170 e 70 (http://www.jegs.com/i/Edelbrock/350/60979/10002/-1).

With the following cam"Edelbrock .539 lift 234/238 duration @ 0.5 (http://www.jegs.com/i/Edelbrock/350/2201/10002/-1).

All that would be coupled with the appropriate intake manifold and roller lifters.

So, what do you guys think of that combination? If I'm not mistaken, I would not have any problem fitting that into a otherwise stock 305.

 

Actually, I just noticed that I might have a problem with this cam. The heads are designed to be used with a 4inch bore. Since the 305 is a smaller bore, I can't have more than .450 lift.

Do you guys know any camshaft designed for roller lifter with less than .450 lift? Otherwise I can always go with flat tappet...

 

Ok, so after a lot of research, I think Trick Flow heads would be best in order to keep compression up (they come with 56 cc chambers).

This would allow me to use a procomp Xtrem energy hydrolic cam ( 270/276 duration @ .495/.502 lift). I would also use procomp roller rockers arms 1.6:1.

Any thoughts?

 

What size are the valves on those heads? I believe the standard 2.02/1.60 are too big for a 305. Also if youre using a roller cam you'll need retrofit lifters which are about $300, plus you'll need a RETROFIT roler cam, not just a regular roller cam.. Honestly you'd be better off just getting a flat tappet cam and a good set of lifters, pushrods, and rocker arms. Just moeny wise a retrofit setup isn't worth it for a 305.

 

http://www.summitracing.com/parts/ed...make/chevrolet

What about this? It has everything you need (bolts, lifters, gaskets, etc.) and is made for 305's. Also this is a great price, a pair of trickflows cost almost as much as this whole kit.

 

http://www.summitracing.com/parts/ed...make/chevrolet

Or this one might be better because of valve clearance.

 

Thanks or the replys,

The valves size on the setup i'm considering ae 1.94/1.5. And i'm aware of the need for retrofit cam/lifter.

The problem with the setup you proposed is that the combustion chambers are 64cc, which would be very detrimental to the compression ratio of a small bore engine like the 305.

Wether it is money wise or not might be debatable, but inmy case the economic aspect is not a big limitation (not that i'm rich but I would rather take more time to finish the project and be happy with every aspect of it).