Need help guys on how to get pushrod length for my build. The motor is from my 91 z28 5.7 . It was a Tpi but converted to carb. Heads and cam im going to be running are Profilers 195cc 64c heads and cam is compcams xr282hr. I still havent ordered my rocker arms but decided to go with 1.6 ratio. How can i find the correct push rod length for my build?

 

http://www.summitracing.com/int/part...9000/overview/

 

The only way to determine the proper pushrod length is to measure the mark the rocker leaves across the valve tip from opened to closed. The proper length pushrod will make the smallest amount of travel across the tip even if it's not directly in the center of the tip.

1.6 rocker ratio are a poor mans cam swap. If your heads can take the increased lift offered by the 1.6 rockers instead of 1.5 rockers then buy a cam that provides that much lift and use 1.5 rockers.

 

TMI:

http://forum.grumpysperformance.com/...hp?f=52&t=1376

 

Especially on fresh build

Could have got more lift and at the same 230/236 duration using this cam

http://www.summitracing.com/int/part...67-8/overview/

 

There's more than just lift and duration. Unless you buy a custom grind cam, sometimes a smaller cam with increased rocker ratio is a better choice if the cam you want has other grind numbers that are more preferred. Generally if it has different lift but same duration, the other things that are different such as LSA and valve timing is ground like that for a reason. You can have 2 different cams with identical lift and duration and they can run completely different from each other when you change LSA and valve timing.

I actually should have said if your heads and pistons can take the increased lift.

Switching to 1.6 rockers moves the pushrod closer to the pedestal to increase the ratio. Some heads don't have pushrod holes large enough to relocate the pushrod and need to be modified. Staying with 1.5 rockers means there's less chance of other alignment problems from occurring.

 

So you guys recommend to use a 1.5 ratio with my xr282hr cam? My profiler heads have the upgraded springs to max 650 lift

 

x1000

 

don't know how many times i have preached this.read the whole thing.

http://www.crankshaftcoalition.com/w..._compatibility