which mild cam for 350 tbi

[kenh]

OK..... FWIW..... The $50 engine was in a race car. It has the stock bottom end, rods and a cast piston. It ran less than one night because of an oil pressure issue. GOOD pressure at idle and the pressure would fade as the RPM increased. The driver, my coworker (mechanic by trade) and owner of the engine, shut it down. He tore it down. inspected all the parts and deemed a bad oil pump. The mains and rod bearings all looked good and he did a light assembly to retain all the bottom parts in order and together. He choose not to use the engines due to the stock parts and the horsepower, or lack of it, that it would support.

For $50 I can get my money out of it if I don't like what I see when inspected.

I plan on using a roller cam in the build. If for nothing else to reduce some of the friction in the engine. Might even spring for some roller rockers???? My goal is not a bunch of horsepower. I want a clean running engine. If I gain some horsepower in the process so be it. I'm not afraid of using a "stock" roller cam. The benefits are substantial over a flat tappet.


Thanks for all the input. Forty heads are better than one....... or something like that!! lol

Ken

 

[Schurkey]

It ran less than one night because of an oil pressure issue. GOOD pressure at idle and the pressure would fade as the RPM increased. The driver, my coworker (mechanic by trade) and owner of the engine, shut it down. He tore it down. inspected all the parts and deemed a bad oil pump.

More likely, oil pump pickup too close to the bottom of the pan, or poor windage control--the higher the RPM, the more the oil gets whipped into froth, and the lower the pressure.

 

[Erik the Awful]

Engine Masters did an episode on roller rockers. Basically, if you aren't revving over 6000 rpm, they're not worth extra expense. I put a set on the motor in my truck before I saw the video. Stock rockers are 1.5:1, but flex enough that they're actually about 1.45:1. If it were me, I'd probably consider a set of 1.6:1 stamped rockers, or just use stockers. If you're going for RPM with this motor, by all means, go roller, but you've already said you want to stick with a milder cam.

 

[L31MaxExpress]

Engine Masters did an episode on roller rockers. Basically, if you aren't revving over 6000 rpm, they're not worth extra expense. I put a set on the motor in my truck before I saw the video. Stock rockers are 1.5:1, but flex enough that they're actually about 1.45:1. If it were me, I'd probably consider a set of 1.6:1 stamped rockers, or just use stockers. If you're going for RPM with this motor, by all means, go roller, but you've already said you want to stick with a milder cam.

Went from 178 hp and 278 tq to 204 hp and 300 tq at the wheels back in the day with a 1" open center TBI spacer, 454 TBI unit and 1.6 full rollers. Engine ran smoother across the whole rpm range. Roller rockers were a very noticeable gain from about 2,500+. I put the rockers on first and later the TBI spacer/454 TBI. Put a set of 1.6 full rollers on my stock Vortec years ago and it was a nice improvement as well. The older Ramjet 350 was rated about 5 hp higher with 1.6 full rollers than its current 1.5 full roller. A HT383 tested with 1.6 full rollers gained 20 hp compared to 1.42 stamped steel. I have seen a stock LT1 Corvette gain 30 hp with stiffer valve springs and 1.7 full rollers.

 

[L31MaxExpress]

Richard Holdners test gained power with the stock springs on even a LS 4.8 but ran into valve float. Added more valve spring and had respectable gains across most of the RPM range. The LS is even a roller fulcrum to start with.

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Also here is an inline 6 tested with a stamped steel rocker and a full roller.

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