Are those EZ heads M.W. size or 440 port size? If 440 size have them enlarge to M.W. size
I saw 50 HP gain on my old pump gas 518 C.I. Duster motor by switching from a set of Indy SR with M.W. size intake ports that flowed 340 CFM at .700 to a set of MCH CNC ported 440-1 that flowed 370 CF @ .700 with every other parts the same
Switching the same heads onto my 526 RB higher compression ratio dyno test mule motor with a little bigger camshaft made 65 more HP than with the same set of SR heads, same compression ratio with both motors due to the CC being 76.0 on both sets of heads
Both motors wanted more air and fuel, the single 1050 CFM Dominator carb was not enough carb. on either motor with the 400-3 or the 440-3 intakes
More air and fuel equals more power