TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
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I have read a bunch of different posts and the quotes range from none to 30 HP gain. How munch HP can I expect from either 1.5 or 1.6 rr? The only real engine mod I have is the Super Comp headers.
If you have actually done this and you KNOW, it would be preferrable to if you just think you know.
__________________ 1990 Trans Am
Hooker Super Competition Headers
Hooker full 3" exhaust
Full poly bushing set
Belltech 2" drop spindles (and springs to match)
Koni Yellow adjustable shocks/struts
Spohn SFC
Spohn LCA relocation brackets
Hotchikis STB
Hotchikis LCA's
Hotchikis Panhard Bar
3.73 Gears
Corbeau Forza Seats
Baer 12" Brakes
I think I put a on that 30hp post. You're not going to see that kind of gain unless your old rockers are bent and give a 1:1 ratio or something Probably not even on a very powerful engine. There was actually dyno floating around here somewhere that netted 14hp changing stamped steel to full roller. I don't think it was a stock engine, though.
I am hoping for about 10-15 hp when I put 1.6 's in mine this spring. The Tech at Comp Cam told me 15-30 HP with my set up is possible......I figure maybe half that is more realistic. I'm changing my valve seals anyway, ( tired of smokey start-up), so whilst I'm there, I.m planning to go with Comp Cams Magnum roller tip rockers (#1416) on my 85 TPI (non peanut cammed). I'll also put in fresh Comp pushrods(#7812) and valve springs ( either Comp Cam # 981, or GM #3911068) to prevent float.
Without a dyno it is subjective to say the least but here goes...
I installed Comp Cams 1.6 rockers on a 305 and the seat of the pants feel was similar to what I felt when I installed the u-drive pullies. Now the u-drive pullies are supposedly anywhere from 8 to 12hp on a 305. I wouldn't be surprised the rockers gave 10-15hp on a 305-350.
I know someone personally that gained 25hp by switching from 1.5 rollers to 1.65 rollers. This was on a pretty big small block with ported aluminum heads.
on that 30hp post. You're not going to see that kind of gain unless your old rockers are bent and give a 1:1 ratio or something 
Probably not even on a very powerful engine. There was actually dyno floating around here somewhere that netted 14hp changing stamped steel to full roller. I don't think it was a stock engine, though. 
