NASCAR314

I see most cam manufactures assume the use of 1.7 : 1 ratio rocker arms in giving duration and lift for there profiles. (Big Block Chevy)

Is there an easy way to convert mathematically from given specs to actual specs if you used 1.6 : 1 ratio rocker arms instead of 1.7 : 1 ???

Thanks,

Les

I can only guess that you're trying to tame a somewhat too radical cam if you're looking to step down from the stock rocker ratio??? Bear in mind that you change the valvetrain geometry by going up or down in rocker ratio, so you'd need to check that & be prepared to order some custom length pushrods.

In any case, if you can get the lobe lift figures on the cam you just multiply that by 1.6 instead of 1.7...If not, you could divide 1.6 by 1.7, take that number & multiply the lift figures given @ the 1.7 ratio to get the numbers you're looking for. I sure hope that makes sense, cuz I'm pretty fried right now.

NASCAR314

Reason for the question is if someone were to keep there stock length 1.6 ratio rocker arms and order a new cam based on lift numbers at 1.7 ratio I'm trying to see what the actual numbers would be.

example: .510 lift x .94 (1.6 divided by 1.7) = .479 actual lift

So if I wanted about .510 lift using 1.6 rockers I would need to get one with specs showing around .542 lift at 1.7 : 1 (.542 x .94 = .509)

Am I close?
Or just break down and buy 1.7 rockers

clem zahrobsky

i never saw 1.6 rockers for BBC because std is accornding to GM 1.73:1, most other people just say 1.7 :chevy

NASCAR314

Sorry clem, my confusion lead to this silly question.
I was mistakenly thinking stock was 1.6 : 1 for BBC :bb
1.7 : 1 is certianly correct, I get all my vehicles messed up from time to time
(Good thing I am not a doctor!)
:leaving: