Any one know if different push rod lengths are needed switching from comp 829 lifters to Crane 66554's?

Check their websites.

Web site only states that the cup is .400 higher which leads me to believe a shorter push rod is needed. Short of buying a pair, I have no way to check if the pushrods are indeed shorter

The 66554 were designed for the tall lifter bore Mega Blocks, having both the pushrod seat and locking bar raised .400" for pushrod and block clearance, as compared to a standard dimensioned roller lifter. The distance from the bottom of the wheel to the bottom of the pushrod seat is 1.723". The 66542 and 66550 (pushrod oiling) lifters have a standard height pushrod seat and locking bar, while the 66543 has a +.120" raised pushrod seat. Regards, Chase

Thanks Chase, I appreciate the information. I was planned on changing out the Comp lifters since I thought one was going punky, but it turns out it's OK.

I'll run the season out on the Comps and change it over to the Cranes over the winter. This will give me more time to get all the pieces together. I bought two Crane lifters for now so all I will need is another 14!LOL!