well got the motor 90% together and found interference. With a 4" crank you'd think it was the rods to block or rods to cam or even pistons to crank. I have a very healthy cam to rod clearance (.33") as well piston to valve clearance (.4"). block has been .060" clearanced for the rods. So what hits you ask?

The darn push-rods. The interference between the pushrods and the cylinderheads actually keep the motor from freely rotating. I'm using 7/16" dia rods and 0.400 lobe lift cam. The heads are AFR.

Basically, I have to take heads apart (shaft rockers too) and clearance them for the pushrods. Then once again, clean the head from all debris.

and reassemble the engine...again!

 

i had to do the same for my heads to stop binding on the guide plates and runners and to center the rockers on my tips

 

ZD1,
I'm assuming you meant 5/16" pushrods? I had the same pushrod issues with new AFR 195 heads during mockup using old head gaskets. I marked them, dissasembled, milled slots in way of pushrods for more clearance, and also clearanced the guide plate mounting holes to allow a better rocker arm alignment to the valve tips which also affects pushrod clearancing. You wouldn't think this should be necessary on a nice quality AFR head. That was the main dissappointing feature for me when heads were purchased but it's all part of the process when using aftermarket parts. I have yet to find an aftermarket part on my car that didn't need to be modified one way or another to fit. Hopefully all it cost you is a new set of head gaskets. I always keep old gasket sets laying around when building and mocking up an engine for that very reason.
Good luck,
Rick
Other issues to note if interested in my opinion.
I usually wind up putting helicoils in the center manifold bolt holes of the head. Why AFR doesn't do this like the rocker stud holes at the factory,I don't know. The short thread length of roughly 1/2" plus 35 ftlb's of torque on aluminum can cause possible stripped thread problems with manifold changes.Also fairing in the oil return passages for better flow back to the sump. The water passages could also stand some attention to remove excess casting/slag and fairing into surrounding areas to help water flow. These are just a few things I feel need attention after owning 2 new sets of AFRs.

 

7/16" push rods , 7.4" length

 

Aint that the truth...Almost nothing is "bolt on".
Worth it in the end though.

 

Are you absolutely sure on that? 7/16" rods look like cigars and weigh a ton when filled with oil. I didn't even use them on BB engines; I built them with 3/8" rods.

Also the pushrod tips need to the match the rocker arm cups.

If they are, indeed, 7/16" diameter it's no wonder you have clearance issues.

Jake

 

There's no reason a high end 3/8" rod won't work in that application.

 

Totally

Jake

 

Why such fat push rods? I have off brand 3/8" push rods in my budget 383 with already hundreds of passes on it!