James71Cutlass

Just wondering what my new to me Rocket 350 will have with regards to HP and performance. He’s what I’m having done.

1974 Rocket 350 blocks and bottom end complete. Very good compression. Took the heads from my ‘71 Rocket had them machines and replaced everything by the exhaust valves as they were in really good shape. Put a comp cam and new lifters in it. Replaced the Tim chain and gears. Putting an Edelbrock 4bbl aluminum intake on it as well as headers with a new 2.5 inch exhaust system. Three speed transmission with 3:42 gears. So what type of performance as I looking at? As well as HP? Thanks

Fun71

You’ll have to provide cam specs, compression ratio (or head chamber and piston dish volume), and which Edelbrock intake manifold, for starters.

James71Cutlass

Ok, I’ll try and find that out. The cam is a CL42-229-4. The pistons dish volume I am unsure of. Whatever came in the ‘74 rocket.

olds 307 and 403

You should be in the high 8 to 1 or just around 9 to 1 compression. I used a cam with 4 less duration but .016" more lift with #7 heads on a 76 350. Until the cam went flat it ran really well. Make sure the cam is degreed and the Qjet is tuned to your motor. I like an aggressive timing curve, 38 to 40 in by 3000, base will depend on the distributor type and 20 degrees of vacuum advance should work nicely. I tried 30 degrees of vacuum advance, I had low speed bucking. Also seriously consider a 2000+ stall, the Jegs 2000 to 2300 stall is an affordable option. I noticed the power band moved up, the factory 1600 rpm stall will be under new curve, although the 3.42 gears help a lot on launch. I gained .6 in the 1/8 going from 2.56 to 3.42 gears. Don't get caught on numbers, it should pull easily through 5000 rpm and launch really nice with the above combo.

James71Cutlass

Thanks for the information.

Oliver442

Anyone have the Ram air hood and OAI 350 set up system? I hope I don’t run into hood clearance , I picked up the edelbrock 2711 for this reason ..

cutlassefi

Ditch the 2711, it’s worthless. Use a 7111, you won’t have any hood clearance issue with it either.

Oliver442

Can’t ditch the 2711, 7111 will not work with the OAI system , the hood will not close and I want the function of the OAI

bccan

Factory air cleaner with 7111 or Street Dom can work with OAI & Qjet but it takes a little bit of work and finesse.

You have to convert the stock air cleaner base from “standard” height to “low clearance” which means you have to effectively lower the outer circumference of the housing in relation to the carb flange hole. I did this decades ago but best I recall it was a combination of a 6x6 under the carb flange to sit the housing on and push down on the rim, picture pushing a barrel ring down a barrel or pushing a stubborn 5 gal bucket cover on. You can also use a mallet or dead blow hammer to hit the carb flange upward. Do your best to keep things square and avoid dents.

Do this in steps as you need to maintain clearance for throttle arm, accelerator pump and choke components. IIRC I may have dimpled housing with a ball peen in one or more of these areas. If running large cap HEI you will likely need to fab a recess in back of housing for clearance like illustrated in a recent post regarding HEI clearance.

Final height consideration will be the foam gasket on top of the OAI adapter. Start with a 455 gasket as it is lower height than the 350 version. I think I trimmed the gasket in half (height wise) with carpet shears to get it to the correct height but make sure you find the sweet spot between sealing to the hood and not pushing up on the hood enough that it doesn’t sit properly.

There are alternative, effective, good looking methods to achieve a functional OAI air cleaner that guys have fabbed or pieced together with pizza pans, wash basins or alternative air cleaner components, do some searching on this site, they worked out quite well.
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