Dynoed my 427so Cobra today.... interesting to say the least!

[neverwouldof]

Originally Posted by Power Surge

Doesn't seem too far off, hp wise. Most 427s chassis dyno in the 390hp range. The torque is kinda low though, for that displacement. Your dyno graph looks more like a stroked Windsor.

Your A/F is kind of whacky, but not too bad. It's a little rich in the mid range, and goes a tad lean at 6k, but it's not so far off that you'd be missing a bunch of hp. I think the dual quads are giving you the crazy A/F lines.

Just for comparison sake, I just finished up dynoing a car with a similar setup. It's a 468 inch 427, alloy heads, with a single carb. The motor "supposedly" dynoed 560 on an engine dyno. On the chassis dyno, it made 398hp/450tq. That was after I tuned it tho, as the carb needed jetting and the dist was messed up only giving about 28 degrees of advance.

Maybe i'm expecting to much.... but how does a 427 go from 603hp at crank to 394 whp when there is hardly any backpressure in a cobra. From all the other threds i read 15% was the going rate. The Dyno shop guy says he usually see's closer to 12's. Viper in there 505 crank and 424 whp with muffler system untouched..... it's crazy i tell ya. Only thing i can figure is the air/fuel getting to engine. If you looked at engine build up... it has some nice pieces!