i read that right you used the 366 heads ? not the best choice very small truck port.pass. car oval port would be the best place to start for heads.366 intake don"t bother wont work use at the the very least edlebrock perfomer. the intake ports on this intake start out about truck head shape.454 and 427 have the same bore size in the beginning 4.250 i do belive. make shure to use proper harmonic balancer and flexplate/flywheel.
