I took my 87' TPI IROC to a rear wheel dyno a couple of years ago in near enough stock form and got a result of 236hp @ 4445rpm and 317lbft @ 3345rpm.

I have now added a complete Edelbrock intake, headers,52mm t/body, TFS heads and a few other bits and pieces.
Took it back to the same dyno a couple of weeks back and they had changed the computer system on the dyno.

The guy doing the runs told me that at 2000rpm he was having trouble getting a proper reading and the dyno was going into " run down" where it stopped measuring the power. He carried on anyway and did a few runs till he thought the readings were right.

The first run he did he told me was the correct HP but not torque. Studying the curves now the engine pulls well up to 2700rpm before the line on the graph goes into a "scallop" shape and falls away. At this point the engine is making 97hp and 100lbft more than the original run.

After a few more runs ( at this point the engine temp is over 220) he says the correct peak torque figure is 324lbft at 3270rpm. Hp on this run has dropped to 242hp.

Something not quite right here. If it made 97hp more than the original combo, and horsepower is a by product of torque, how can the first torque result be wrong?.
I know the stock cam will kill it in the higher rpm range, but does this make sense?.

Thanks.

 

I'd try another dyno. Don't make any decisions on changing things until you get a confirming dyno reading. My guess is that it won't confirm what this one says.

FWIW, a 100 lb-ft increase at 2700 rpm is very unlikely, and that would only be about a 51 hp increase at that rpm. IOW, 100 lb-ft, 97 hp and 2700 rpm don't compute.

Good luck.