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What is a minimum push rod to head clearance. I have a couple rubbing. I put masking tape on the pushrod to make it .020" thicker to check clearances. Any other measuring tips? BBC if it matters...
 

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You don't need much...

From Manton:
"Do not allow over clearance for the pushrod. This may cause the pushrod to move around or deflect more then needed. Clearance of .010 to .015 on aluminum heads at the closest point of contact is sufficient. We also need .015 to .025 clearance at the lifter bushing or tie bar of lifter. The surface of the cylinder head or engine block can often be utilized like a large guide plate and dampening device which stabilizes the pushrod. Make sure there are no pushrod binding or interference problems when turning the engine over during assembly."
 

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I am not a pro, but what I do is wipe high spot blue over the push rod, turn the engine over. When it no longer leaves blue on the head, it's good to go.
 

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I am not a pro, but what I do is wipe high spot blue over the push rod, turn the engine over. When it no longer leaves blue on the head, it's good to go.
When I was building SS/AH Motors this is jow I did it. Used a die grinder to finesse it.
 

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Mine actually rubbed the black off of a couple of my pushrods.
I've had a few like this as well. Very slight rub, can still slip a feeler gauge in there if you work it....I don't make any more room than I need too....less grinding time!!
 
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