rocker ratio

[waroc]

   what is the difference between 1:5 ratio and 1:6 ratio rockers?  is there an advantage to running the 1:6 over the stock 1:5 ratio?  thanks  mark   

[andy74]

the 1.6 is a larger ratio,so if you run them the lift is multiplied by 1.6 instead of 1.5-if your heads and combo warrant the higher ratio,its probably cheaper to swap to a cam with more lift,a cam that has a .400 lift with a 1.5 ratio is .600,where the 1.6 increase that to.640-just as an example-my 2 cents

[firefighter3931]

  is there an advantage to running the 1:6 over the stock 1:5 ratio?  thanks  mark   

Mark, the answer to that question is ; It depends. In some instances a higher ratio rocker will help, particularly if the heads have been ported and there are other engine mods....headers, high rise aluminum intake, big carb, better than stock cam etc....

On a mild engine build there isn't much to be had with a simple rocker swap, inmo.


Ron

[Duey]

Ron, on that note, I'm going to get a set of the Crane ductile iron adjustables, so I can get my KV-3...should I stick with 1.5:1? 

I haven't pulled my heads yet to see how deep the pistons are in the holes...given my build spec'd 10.5:1, I'm figuring the 2355's are very close to the deck ( 0"-0.015" ?)

My gute feel is stick with 1.5, the KV3 has plenty of lift (.575") and 1.6 would be .613" (less the lash, of course)...would 600" be pushing the limit of getting my 2.14/1.81's to close to the 2355's?

Thanks!
Duey

[firefighter3931]

Duey, the 1.5's are fine. The Engle grinds are pretty agressive to begin with so adding some additonal rocker ratio will put a beating on the valvetrain. If aluminum heads are in your future....the 1.6:1 rocker could create piston to valve clearance issues. Remeber that the reliefs in the 2355's are located for an oem cylinder head....and the aftermarket heads have the valves located in the non-stock location as well as being oversized. There's allways the option of flycutting the pistons for additional clearance if you need it....but you shouldn't with the KV-3.

Ron

[waroc]

   thanks  fellas   mark