Have any of you had to use push rods other than stock length when building a motor? I'm puttin' together my 383 with cast iron heads, stock deck height on the block, Comp cams Extreme Energy flat hydraulic, Comp cams roller tip rockers. The factory rods are 7.80 inches, I want to get a push rod length checker but I don't know if I'll be needing longer or shorter than stock. The tools are either 6.80-7.80 or 7.80-8.80, it's kinda' like a micrometer with a limited travel to check the correct valve train geometry.

 

Are the iron heads a stock casting or aftermarket, that and the type of rockers that you use dictate what size pushrods you need. What kinda Comp cam did you get, I just bought a 280H Magnum, and I need to get long slotted rockers because its a .480" lift! For as much as they cost, I could almost get full roller rockers.

http://www.compcams.com/information/Products/Pushrods/

 

The heads are stock and didn't need to be milled. The cam is an Extreme Energy flat hydraulic CL12-234-2, less than .500 inches of lift. I'm using their whole cam kit with springs, lifters, and comp's magnum roller tip rockers.

 

Check it out, but its with Dart heads:

http://www.compcams.com/Technical/Dy...56H-10_001.asp

 

Thanks for the chart Clayton, I didn't see any reference to push rods but like you said, they were using different heads.

 

I would venture a strong guess that if the heads weren't milled and you are using the stock block, that stock length push rods will do fine, are they the rockers that have the posi-lock nut in the center or do they have the little doughnut thing (can't remember the name, fulcrum?) and the stock oblong nut? My buddy used Edelbrock heads and full aluminum roller rockers with stock pushrods just fine. I just called him and he said it depends on where the tip of the roller rocker sits on the tip of the valve stem. Put it all together with a couple stock pushrods and see where the tip of the rocker arm sits, if it rests in middle of the valve stem, you are good, if its to far to the exhaust side, you gotta get shorter, if its to far to the intake side, you gotta get longer.

 

I'll have to find a solid lifter to check the travel, the hydraulics wont be pumped up and the plunger will give me false readings. The rockers have the ball style fulcrum similar to the stock rockers. I'll definitely start with the 7.80 rod and check the entire path of the rocker tip. I appreciate the info from your buddy.

 

I forgot, he said he bought +.100" and didn't need them. I think he bought crane roller rockers, they were gold thats all I remember... Good luck, I am doing a cam and head swap this weekend, so hopefully I can get some audio up to show everyone how cool I am now that I my Corvette will be fast... not that 190 hp is... slow...

 

If you don't have a solid lifter, you can use a hydraulic with a light valve checking spring in place of the stock spring. Just a thought.

 

buckshot,
Why not call "Comp Cams" or someone like that and get the "exact" and "correct" info on what rods to use instead of guessing. Not just for expense purposes, but for the wellness of the engine, I'd talk to the Cam people who know just what to run w/ your set-up. "Better to be safe than sorry." Good Luck.