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... because they can work really well, once finished properly.
I have the EM470 heads and ran them until I switched to alcohol, and I didn't want to take a chance with the epoxy in the intake ports. So they are a back up for a gas setup.
My Indy 440-1 heads run about the same as the highly modified/ported EM470 heads. But my E85(ethanol) combo makes a little more power since it added injection, a bigger cam, more CR, with the fuel. So the EM470 heads are about the same as a decent set of Indy 440-1's (not the CNC version).
In good air, they went 9.29 in my 3220 pound Dart, with a flat tappet cam.
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