My engine is a 1989 IROC 305 roller (TBI/5sp manual)...runs great, about 60K miles..stock engine. Don't know the factory cam specs..and can't find them. The engine lacks pulling power and the rocker lift looks very minimal..not scientific..but the cam lift looks minimal..as compared to my other SBC's.

I want to try another cam anyway and got a good deal on a new 305 HO cam (roller 1990-1992), what's the chances of my current ECM and MEMCAL (using 1.5 rockers) working with this cam:?

Intake lift w/ 1.5 rockers .410

Intake Duration 252...or 190 @ .050

Intake lobe centerline 106

Lobe Separation 110

Exhaust lift w/ 1.5 rockers .426

Exhaust duration 256 advertised ...195 @ .050

 

as for your computer I can't answer, but be aware of the following: Your heads are NOT the same as the TPI 5-speed 305s got. You have swirl-port heads that don't flow and don't respond to bowl-blending. Yes, you can get one of these engines to turn 6200 rpm in first gear, but there's no pull above 4800. You now have 8.8:1, not 9.1:1 as GM claimed. I'm a professional automotive machinist, I've cc'd this stuff. Also, your TBI intake and tiny exhaust system are limiting your power.
I think changing this cam will just reduce your low-end torque, and the heads will cancel any real top-end improvement, however it may feel.
My advice would be to focus on the exhaust system, putting better gears and a posi in the rear axle, and saving to put together a 350. Decide on a torque converter after you get the 350 in. That's my take after 2 years of playing with my own TBI '91 RS and an '88 TBI Camaro.

 

Atilla the Fun

First of all..thanks for responding, but, my only concern is ...will the cam work with my current ECM/MEMCAL. Really don't care about speed…. Essentially there is unacceptable torque now. The exhaust has been addressed and I'm running a 5 spd with rear gears. (BTW: I have TPI setups, 350’s and even a good to go 454. I want “this 305” to just have more pull power without replacing it).

Would have been better to just state my current cam is shot (because it is) and ask: will the 305 HO cam be a compatible replacement. i.e. is the lift, duration and LA within GM computer compatibility? (I think it is..but want to be sure).

Thanks again

 

From what I have read, you'll have no problems. Its a small step up from the factory cam you have.

An LT1 cam might be a better idea.

I am sure some one else will chime in.....

 

Thanks avro206

I agree on the LT1 cam...however, got a super deal on this one. Looking for a slight improvement in lift without going on a parts/components replacement scenario. (ie custom proms, fuel regulators, injectors etc)

 

lemme try telling you about the tire-spinningest 305 I ever drove. I built it myself, a '91 block bored 60 over with flat-tops. Used 1976 305 heads cut for 1.94" intake valves, mild porting, exhaust ports polished. GM ZZ4 intake, Edelbrock 600 carb, Accel 59107 HEI, Hedman shortys with Y-pipe, Dynomax cat-back. B7M TorkMaster 2400, 700R-4, 3.42:1, 215/60R15s. I bought a ZZ4 cam last, as the ZZ4 's 405 tq impressed me, I hoped for 360 ft-lbs. I only had traction problems, at all, and then to excess, when running COMP's HF, non-roller, 206/212-112 425/440. I credit it to the later exhaust opening, the reduced overlap, despite the loss of lift. At that time, the HR version was NOT a shelf item. If you buy it, you 'd get 480/488 lift with stock rockers.
That should help torque even more. Anyway, with the ZZ4 cam the traction problem went away.