Dyno Day Results
Well, the big 428 (actually 434 with a .035" overbore) did pretty well and leveled out at 432 hp at 5000 rpm and 502 lbft torque at 3700 rpm through the regular A-body/2nd Gen F-body RA manifolds with 2.25" outlets. Knowing the long branch factory manifolds (2.5" outlets) makes a few more hp & tq across the rpm range would put the hp to 435 and tq to 505. Dan is very satisfied with the results and called it a day after a dozen pulls. The motor never missed a beat and ended up liking 38-40 degrees total timing and the jetting he started out the day with (I'll have find out what that was). It lost power when they tried richer and leaner mixtures. The motor has 10.75 (+) actual compression and an 068 cam with 1.5 stamped rocker arms. Most runs showed the power peaking at 4800 rpm and hanging on at 490 hp (+) until 5300 rpm before dropping off. 428's are very impressive motors to say the least!
Dennis
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