Comp Roller Rockers HP gain??

[GEARS]

Hi everyone,

I have a HT3.4 in my 1986 S10, with a Holley 400 cfm TBI, ported intake, MSD coil, Edelbrock headers, and a large single no cat flowmaster exhaust.

Some future engine mods I have in mind are a wet NOS kit (between 50-75), MSD Digital 6 (to deal with the NOS), Intrepid Electirc fans (just becuase...), and Comp 1.6:1 Magnum rollers.

One question about these rockers... Comp advertises a 15-30 horsepower increase by installing them on a iron head 2.8. To me that seems a little far fetched, but then again I could be wrong?? Do you guys think I'd actually see a 20-25 HP increase using these on my HT3.4??

[geoffinbc]

On a big V8 with stock stampings you might see that gain. But on a V6 that is 1/4 the displacement i doubt it. 10HP/10lbs of torque would be the most I would give it.

But the other benefits are reduced valve guide wear, more accurate ratio and slightly reduced oil temps. For less than $150 they are well worth the money.

[GEARS]

I read last night that some people with the iron heads need to shave the pushrod guides... otherwise the rods will rub and/or break the guides. Is that true??

@betterthanyou.... I am a ferry ride away from you... Your site was very helpfull with the engine swap! Thanks for sharing your 660 knowledge!!

[robert 1980]

I see there is two sets of comp rockers on the 60 degree store.Which would be better???Im doing a 3400/3500 hybrid with a high lift cam.10 extra horse sounds good for 150.

[3400-95-Modified]

Robert hes going from a 1.5 ratio to 1.6 so thats why he'll see a gain of possibly 10hp, our 3x00 rockers are already 1.6 Ratio. There were NEVER any roller fulcrum rockers that fit 3400/3500's made for us when there was a big deal that there would be. The only ones known to fit, which still need modification are the Comp Gold Rockers, and a few have noticed fast wear on them and havent been able to explain why. Leave well enough alone in my book.

[geoffinbc]

I read last night that some people with the iron heads need to shave the pushrod guides... otherwise the rods will rub and/or break the guides. Is that true??

@betterthanyou.... I am a ferry ride away from you... Your site was very helpfull with the engine swap! Thanks for sharing your 660 knowledge!!

Never had a problem on my two builds. But you always need to check.

[ericjon262]

IIRC, a stock 305/350 tbi flows somewhere in the ballpark of 670 CFM, and probably alot cheaper than a holley unit...

[geoffinbc]

That was not his question. But a stock 4.3L/5.0L/5.7L TBI is the same size as a Holley TBI for the 2.8L and they both flow around 400CFM.

[GEARS]

Well I'll just go ahead and order the rockers. If I find that the rods hit the guides, I'll just shave them down a little... no big thrill.

I will keep you guys posted about the install and the difference... but what I can tell you guys is that I can't wait for my NOS!!!

[3400-95-Modified]

Nitrous is fun... It's got me in the 12's