Quote:
Originally posted by Mike Simard
What changes were made between the runs? Your title implies that the car was the same both times and 2 dynos disagree but you said "he tried to undo all the work the shop in PA did ". So what did they change? The specs do sound like a 400+ hp engine. What heads? Also, what was the timing each run?
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Both dynos are Dynojets. The heads are Edelbrock RPM Performers.
The moron who first worked on my car here pulled the brand new autolite 3924 plugs and put in motorcrafts. Why? "the motorcrafts are what are used on a stock 1969 Mach 1." He said that my fuel pump was bad so he replaced it with a Scott Drake fuel pump because "that's the closest to an OEM part." WHile a perhaps a good fuel pump for a 300 hp car, definitely not the best choice for a 400+ hp car. Next, he reset the timing to spec for a stock 1969 Mach 1, not what was appropriate for a significantly modified car. He pulled the condensor from the distrib and put in a stock one for no other reason than the one that was in there was not spec for a stock car. The new condensor promply failed on the highway on my way home. There is no room in this guy's universe for any non-stock part on a classic car.
Between PA run and the NL runs and after I got the car back from the first "expert", I swapped out the ignition and distributor for a MSD 6AL and Pro Billet (HEI) Distrib. and new 8.8 mm wires. That is the only difference. Should I lose HP by installing an MSD HEI distrib and ignition?
After my first tuning fiasco, I took the car to a second shop for a decent tune. The dyno run in PA showed the 351 rwhp at 6200 rpm on a dynojet. The two runs here in the NL were also on a dynojet and they have showed 280 and 293 hp at 5400 rpm. I guess I cannot say that these are an apples to apples comparison given the difference in the rpms. I currently have a rev limiter in the 6AL for 6000 rpm. I will have them install a 6400 rpm rev limiter and see if they cannot get close to the PA dyno numbers once they have fixed the carb problem.