Pushrod Length help

[BLACK85GT]

I am going to be putting my engine together and need the proper procedure for checking pushrod length. I have a pushrod length checker and I need to find the correct pushrods for my new heads etc. My setup is alum. holley heads with pedestal mount scorpion roller rockers. It is a non roller block. Is there a source I can go to for step by step instructions. I cant find it in the haynes manual.

[302 LX Eric]

I assume that the instructions for your Holley heads don't say anything about it? I have TFS TW heads and they have a nice procedure write-up on how to check for proper pushrod length in their instructions. I followed them and had success.

Here is a link to the instructions. It's covered under section 5.

This may at least give you a basic understanding of steps involved. It worked well for me - I just took my time and had a few cold ones.

Hope this helps.
E

[Murdock]

1. With the cam, crank and timing set installed, bring number 1 cylinder to top dead center on the compression stroke.

2. Install the two lifters that will be used for checking on the intake and exhaust lobes of the cam for number one cylinder.

3. Bolt the cylinder head on the block with no head gasket. (Do not torque the cylinder head, just make it snug).

4. Install the guide plate and rocker arm studs. Again do not torque the studs, just make it snug

5. As a starting point, adjust your checking pushrod to the same length recommended by cam manufacturer for the cam and lifter combination you are using.

6. Install the checking pushrods in the engine.

7. Take your black magic marker and color the tips of the intake and exhaust valves.

8. Install the intake and exhaust rockers and adjust the rockers to zero lash.

9. Rotate the engine over by hand several times.

10. Remove the rockers and note the contact pattern the rockers made on the tip of the valve.

11. If the pattern is centered on the valve tip, pushrod length is ok. If the pattern is wide to the exhaust side of the head, your pushrod length is too long. If the pattern is wide to the intake side of the head, the pushrod is to short.

12. If adjustments need to be made, remove the rockers, recolor the tips of the valves, lengthen or shorten the adjusting pushrods as needed, reinstall the rockers and rotate the engine over again by hand. Repeat the process until the desired pattern is achieved.

13. Once the desired pattern is achieved, remove the checking pushrods from the engine and measure them. Take that measurement and add the compressed thickness of the head gasket being used. The sum of this will be the correct pushrod length for your combination.

[blue oval 50h]

Also check out

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