Single carb 425 was reported to produce 340hp and the dual carb was reported to produce 360hp. :3gears: Factory dual carb 425s are called a Super Wildcat. DISCLAIMER - Im not a performance guy.
Need some nailhead info please/ not for me but co-worker. My knowledge as far as performance was that larger valve cannot be installed on nailhead.? Can u or not?
You can. One set of heads here have 1.94” intakes (1.87” stock). They needed to be unshrouded for any decent CFM gain - Especially at higher lifts.
I cut some finned drums for a customer / he said he had a 66 riv. 425 that had been sitting for 25 years. Out of the 4 drums only one was warped - he other 3 cleaned up with minimal cut. But he said he was soaking. The motor.