Pushrods

[oldgasser]

Could you shed some light on how to correctly measure a pushrod for a 312 engine that I'm in the process of building and have to order a new set.
I have excellent re-built shafts & rockers & the rockers have a 3/8 ball to receive the pushrod cup.
Thank you for your time.
Ron.

[hiball3985]

Unless some one else can provide something different the best I can remember is the measurement is taken from the ball to the inside of the cup. I never have been able to figure out why there were two different lengths available.

[gasman826]

There is a tool.  It's like a push rod with threads in the middle.  They come in different lengths.  You get one closest to the stock length and it screws apart until the correct rocker geometry is achieved.  Kinda' like an inside mic.

[SkylinerRon]

All 57 Y-Blocks are 8.188" except w/the blower cam 8.138".
54-55 are different.
Goodluck,
Ron.

[oldgasser]

Thanks Fellows for the information stated.
Much appreciated & again thank you for your time.
Cheers Ron.