[chris txstang]

I will be swapping my heads for the RPM heads at the end of the week. I ordered the edelbrock bushings and the teflon seals. I was going to order hardened pushrods, but I have heard that 302 and 289 heads use the same length , and I have heard that the 289 pushrods are a tenth shorter. Could anyone help me with this? Also, would it be worth it to polish the exaust and the chamber, and how much do I mill off to get it from 60 to 58 cc's?
Thanks

 

[Nastystang]

I have heard that milling .010 will net .7 CC decrease

so if that is correct you will need to mill .030 to net 2.1 cc`s.

I am not positive so I would suggest more input from others on the forum.

 

[393Clevor]

It all depends on the shape of the chamber.

 

[chris txstang]

Does anyone know what is the correct pushrod length? I guess if I mill off 2 hundredths that the slightly shorter 289 pushrod would be the safe bet. Any input?
Thanks

 

[67stang]

Invest in or borrow a push-rod length tool. It's the best way to know for sure what you need. Better to know now, than to find out later the hard way...

 

[Fast2]

There are instructions on how to make a push rod length checker on this site. You cut an old 5/16 push rod in two, and tap the two pieces with a 1/4 x 20 tap. You thread in a 1/4 x 20 stud with a lock nut and wahlaa and presto. I did one last week, works great. I think you can find the artical under tech here at Ford Muscle.

About the milling. Here's my experience. On a set of either 165 or 185 AFR heads (58cc) it takes .006 flat mill per cc. You would be looking at roughly .012 mill work for the 2cc's

Dan