94sylvan

Hoping to hear from the experts here (Ahem... SB, maybe even Bob Madera, but feel free to chime in with your personal experiences) It seems that with the tighter duration limits of marine use camshafts that the general power increase when switching from 1.5 to 1.6 ratio rockers on a small block would be significantly more noticeable than with our street warrior brethren. Is it worth the couple hundred dollars to find out or like with bigger cams is it still only a 5-7 hp gain?

I'm in a rebuild right now on an almost new engine thanks to engine builder leaving a broken drill bit tip in my crankshaft from drilling to balance. (sliced the oil pan open and lost oil pressure) shut it down quick enough that didn't hurt anything but I found the drill bit pieces and shavings in the bottom of the pan. So while its down I'm going to adjust cam timing back to straight up, finally building some extended risers, adding an engine oil cooler, thermostat, and remote filter, and made the switch to a 780 holley vac secondary carb. (side note: 1409 edelbrock will be going up for sale very soon...)

Engine specs: 385 cu in. 4.040 bore x 3.75 stroke. ProMaxx Maxx series 183 Alum. heads 64 cc with 183cc intake runners. 250 cfm at .500 edelbrock rpm air gap intake with 780 holley. Cam lunati voodoo 60111 219/227 @ .050 .515 / .530 (with 1.5 rockers) 112 LSA 106 ICL ( I had it set up at 103.5 ICL will be reinstalling at 106) Engine ran good out to about 51-5200 rpm in its previous form.

Paxtonspeed

I would say, if you already have the 1.5 rockers run them. If you were starting from scratch and had to buy rockers anyway, buy the 1.6 rockers.
If you have it down and wanted to make a change, because you were unhappy with performance, you would be better off changing the cam for around the same money.

Since I was building a whole new engine, I went with Summit 1.6 RR's.
My cam is a Comp Extreme Energy cam XR270HR 218 / 224 110+4 .528 / .534 lift with 1.6 roller rockers. .495 / .500 lift with 1.5 roller rockers.

SB

iTrader: (1)

1.6 intake / 1,5 exhaust typically good for 10-15hp based on ET gains, not dyno, but with cams in the say ,mid 230 at ,050 range and much larger.......never played with them on such mild cam shafted small blocks. So, I dunno. If putting together a motor with such small cams I just tell people get 1.6/1.5 or 1.6/1.6 just because. LOL. if they get 1.5/1,5 i don't say anything. No biggie, I'm sure.

Paxtonspeed

I guess it would also depend on if your heads, and springs could handle the extra lift.

Ryan00TJ

iTrader: (8)

The 1.6s will add lift and a tad more duration. I ran 1.6 on the intake only with a Comp XM276HR cam in a 355. If your engine combo can utilize the additional lift/duration it can increase power. IMO, it's better to get lift/duration from the cam spec and keep the 1.5 ratio.

GPM

The 1.6 rocker will increase ramp speed, lift and duration, RPM range and seat timing stay the same. A larger cam would probably be a better power choice.