pushrod clearance

[TheCraigMachine]

Can you run early LA heads with the small pushrod holes on a later model roller block with OEM roller cam gear? Can the smaller holes be clearanced to accomidate the different pushrod angle, or is one limited to using 302s or 308s?

 

[MRL Performance]

They are not only larger on the late model heads, but they are in a different location. You can grind to make room, not a problem, just take your time and do a lot of test fits to get it right.

 

[moper]

I disagree Mike. IIRC they are larger on the 308 type castings - might be on others but that casting sticks in my head for some reason.

You can clearance the pushrod holes, yes. I'm pretty sure it's going to be mandatory if you run the hydraulic rollers with the early heads. I know it's needed on the LA RPM heads to run the factory roller lifters. It's best done as part of mock up so you can make sure there's plenty of room, but before the heads are fully "final assembled" because you'll be creating iron dust/filings. Also - if you can afford the best 5/16 diameter you'll save some grinding over using a cheaper 3/8 diameter.

 

[MRL Performance]

Yes thats what I said. They are not only LARGER on the late model heads(302 & 308) they are in a different location than the early heads.

 

[moper]

lol.. Ah - missed that part. Thanks Mike!