In terms of getting some 300 cfm out of the E heads The main pinch point in those heads on the Intake is the neck down in roof height on back to the Intake flange starting at the crown of the short turn and how much the common wall head bolt boss sticks out into the port.
Unless you have a flow bench do not do anything in that massive 1.920" valve bowl other then a really light blend, like only removing .010" at most lest you drop off much needed low lift port velocity that these heads are short on!
Another thing, bo not polished out your rework with anything but a 80 grit roll at a slow speed other wise you will aggravate even more the not so great wet flow conditions these big port heads have out of the box!
In terms of dropping the compression with the 72 cc E heads the only way to do it accurately is to get your pistions dished unless you work with a shop to get a chamber maching program set up to rework the chamber on the spark plug side.
You could start off in the heads by first CCing them and then unshrouding the sides of the chamber ( the extreams of the Intake and Exh valves ) and then CCing again to see where you are.
With the way the 72 CC chambers are machined stock I find that I gain 3 CCs when I do that.
PS, I would say for sure that with your cid your going to need a good amount more then a 230/234 Cam to attain 168 mph!
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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!
Last edited by steve25; 07-28-2020 at 06:37 AM.
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