Rocker Arm Ratio/Camshaft??

[gbodyera]

I have stock 1.5 ratio rocker arms on a chevy 350. I am thinking of upgrading to some Harland Sharp Gold Series 1.6 Rockers or some Comp Cams 1.5 roller tip rockers. If I do change the ratio, do I have to change my pushrod length? If I upgrade the cam do I have to select one with lower lift since the 1.6 ratio is used and adds more lift?

 

[shotgun]

If I do change the ratio, do I have to change my pushrod length?

You should not have to, just set 1/4 past zero lash.

If I upgrade the cam do I have to select one with lower lift since the 1.6 ratio is used and adds more lift?

Yeah, you could, but why do it then?

Most people add higher ratio rockers to gain lift and a few degrees of duration. If you go with a lower lift cam you just defeated the whole reason for adding 1.6 rockers!

 

[Clanceman427]

Just know how much you have left before coil bind. Knowing this, you'll be able to then see if your additional lift from the higher ratio rockers will or will not risk coil bind, based on your cam lift specs.

Kevin

 

[drogg1]

Another benefit to roller rockers is many are lighter weight and have less friction than stock rockers which also increases hp. Thus the reason for upgrading to roller rockers without changing the ratio.

 

[megaladon6]

actually you do need to change pushrods. the different ratio causes the rod to ride differently--ie improperly--this adds stress and wear to the entire valvetrain and IIRC, increases the chance of bending a rod. i've talked to a number of people about this and the consensus is that going to 1.6 really isn't worth it on a street motor. you spend so little time at peak lift and there's so much extra stress on the valvetrain... but going to full rollers is a great idea and restores a decent bit of power. BTW, the roller tips do very little except reduce wear. they're nice to have, since they're cheap and much stronger than stock, but a true roller rocker blows them away.