Bob2of3

iTrader: (11)

Do I need to order the 7.35" pushrods? Has anyone used the Trick Flow pushrods that seem to have the same specs, 7.350" 5/16 dia, .080 wall thickness.

<img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />

CHRISPY

It is always a good idea to run a custom length pushrod instead of shimming etc. You want to keep valvetrain geometry as close to stock as possible.
Cheers,
Chris

JS

iTrader: (4)

Bob,U need to check it..
U just cant assume a 7.35in. is the right length..
Joe milled my heads .016 which doesnt need a shorter PR...


Now for my prediction!!
I run 11.40@118 at a race weight of 3550lbs
U weigh 3000lbs,I'm sure your gonna run something on the lines of a Hammer cam?From what Joe told me u have 1 mean set of heads ready to bolt on...

So.....The prediction is :
10.75@124

Good luck!!!
The Skipper

JS

iTrader: (4)

Patrick,Its funny u say that because I checked my PR height at my boss's house and the stock PR is .025 long for my setup..


I never bothered putting the shorter PR in because
it was only .025...

FWIW
I'm switching to Cartek's Heads/Cam and Julio has the correct PR heights already figured out.Good info Patrick..

Gilligan,make sure u check it...
The Skipper....

Patrick G

iTrader: (14)

Here's the dilio:

Stock pushrod length is 7.400. With stock heads, that puts the pushrod about halfway down the plunger of the hydraulic roller lifter. There's about .050" +/- of travel from the center of the plunger (.100" total) and ideally, you want the pushrod toward the top of the plunger. Why? Because at high rpms, the lifter will want to pump up. So if you have the lifter .010" from the top of the plunger, you're still in good shape if the lifter goes solid. If you mill the heads .020", the plunger is now .070" from the top of the plunger. If you turn a lot of rpms, the lifters will pump up to the top and go solid and your valves will never close all the way. A .050" shorter pushrod would work very well, but like Chris and JS said, you need to check it first. You need to see where 0 lash is, then how far down the plunger travels. In a perfect world, you only want .010-.020" of plunger travel from 0 lash.

JS, even though you're running stock length pushrods, I bet you could run more rpm with shorter pushrods. Your geometry would be better. Pushrods that are too long will give you the impression that your valves are floating (at high rpms) because of poor spring pressure. They're actually floating because the lifter is pumped up and not closing the valves all the way.

[ November 24, 2001: Message edited by: Patrick G ]</p>