340 pushrod issues

Hi Guys,

Well after the last post I had, we ordered a full rocker/shaft/hold down kit from Harland Sharp for this engine. Just a breakdown, its a 1970 340 block, with untouched X heads. The engine owner purchased a Howards hyd roller cam and retro fit lifters. When we started to measure for pushrod length, we realized that the pushrods have some pretty severe clearance issues. Maybe this is normal for a set up like this, but it looks like the pushrod hole in the head would be much more effective if it was oval and not round. It's possible the pushrod cup in the lifter is a bit higher than oem, and if so that might account for some of the clearance issue, but even if you simulate the cup being deeper, there still will be problems. I guess I'm posting to see if you Guys have run into this before. We purchased the rocker kit from Mancini's, they were unaware of ever hearing anything like this before.
Thanks!

What ratio is the new set of rockers?
Untouched X heads with hydraulic roller lifters may equal opening up the pushrod holes.
5/16” pushrods?
BR3 may be able to help with your situation, but the new lifters are taller than the OE making the clearance a possible issue.

They are 1.5s. I agree, the higher cup height isn't helping at all. I did a bit of internet surfing on this after I posted, and it sounds like some of this comes with the territory.

Yes, 5/16" pushrods

On mine, the Crane Hyd roller lifters were much taller than a factory flat tappet. The pushrod angle is far more severe resulting in pushrod to head contact.
Doug

Got it, thanks for the replies Guys. Time to get out the Dremel...

What you’re experiencing is why the heads that were used with factory HR lifter cams had much bigger PR holes in them.