dean51267

some months ago had two 454's on the dyno, peak HP about 5300 rep at 442hp. Motors spun main and lots of other problems due to thermostat problem.

rebuilt motors, did it right, new pistons, re size rods, balanced assembly, new forged crank, new valves, all that stuff. Same cam, different roller lifters (others had to much metal to trust). Only real difference is cam now has thrust washer, motors are balanced, and different brand of lifters. BUT it lost 40 hp on Dyno.

Guy running the dyno is NOT screwing with weather settings or calibration.

There is a factor that has something o do with environment, not sure what this number is called, it was bouncing between 103 and 104 on the first run, and a solid 108 this time.

Tomorrow we start looking to what is going on, we left tonight knowing motor was running well, just lower HP numbers.

Motors are Gen 5 454's, standard bore, 540/235 cam, dart heads, air gap intake, elderbrock 750 carbs, big tube headers, merc stock ignition, 10:1 compression, flat top pistons with valve reliefs cut out, (originals were dish with no valve relief). One has been run, the second has not, we pulled 6 runs up to 6000 rep each and results are scattered between 370 and 405 hp. Orginally we consistantly could pull runs at 440 hp +/- 3 hp.

Timing on original run was at 34 degrees advance, this time was 36 degrees. Obviously this needs to be adjusted, but it is small adjustment.

We will mess with motors more tomorrow, but looking for places to start. Thanks!!!