If you’re going thru the expense of porting the heads then a valve job should be done anyway. Not only to have fresh seats to mate up with your hopefully new valves, but because the factory valve job only uses about 94% of the given valves diameter.
For example with the 2.11” OD intake valve used in the 6X heads the stock valve seat OD is 1.98” or so..
A 1.98” valve seat OD makes for a curtain area of 6.21”, a 2.11” if used provides 6.62” .
The later provides 6.5% more flow area for any given valve lift used.
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs!
And he was not talking about 1/8 or 1/4 mile ETs!
1) 1940s 100% silver 4 cup tea server set.
Two dry rotted 14 x 10 Micky Thompson slicks.
1) un-mailed in gift coupon from a 1972 box of corn flakes.
Two pairs of brown leather flip flops, never seen more then 2 mph.
Education is what your left with once you forget things!
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