My set up will be C heads, hydraulic roller with .535” lift, HS 5016 rockers. Just a cruiser.

Harland Sharp footnote says pushrod holes must be drilled to 9/16. I plan to use 5/16 pushrod (Trend or Smith).

Wondering if I actual need to drill out heads or not…as per Harland Sharp. Anyone have working knowledge of a similar set up.

I’ll eventually mock everything up to know for sure…but all the darn back orders for parts make it difficult.

If i knew for sure that heads must be drilled for clearance even with 5/16 pushrods, i could knock that out while waiting on parts. But don’t want to if It’s not absolutely required.

It appears hydraulic roller lifters slightly increase the unfavorable push rod angle since they’re taller (i assume they’re taller than a non-roller)

thanks,
Adrian

 

I would do a try and see before drilling.... what is your block? 455?

 

It’s a 400 G block.

 

I also recommend waiting until you can mock up everything. Even with 3/8" pushrods and high lift, I only had to egg shape the end of the hole a bit on the block side of the heads. I used a die grinder with carbide bur. Drilling the holes is not so easy, as the bit will tend to catch, jam, and try to spin the head, etc. It also removes meat in places where you are better off leaving it.