I've got a 79 F-150 with a 532 in it. Current headers are 1 3/4" primaries and 3" collector, flowed by 3" dynomax ultraflow mufflers. How much hp do you think I would gain by changing to headers with 2" primaries and 3 1/2" collector, flowed by 3 1/2" magnaflows ?
Motor spec: 532ci, ported edelbrocks and victor intake, pro-systems 1050 dominator, xr292 cam, 10.7-1 comp.
Motor spec: 532ci, ported edelbrocks and victor intake, pro-systems 1050 dominator, xr292 cam, 10.7-1 comp.