Tylleys slant 6 turbo
thats a really nice motor and all but with 600hp you should be going faster then 11.50's...
Using elapsed time to quantify horsepower is a very unreliable way to determine horsepower under any circumstances; mph is a lot more accurate.
Example, I have a friend who raced a serious A/SA '69 427 Camaro and it ran CONSISTENT low 10.30s (with a 60-foot time of 1.31, usually) at a consistent 127 MPH. Hardly ever better than 127.
Ryan's very fast '66 Valiant also runs 127 MPH, but doesn't 60-foot like my friend's Camaro, so his e.t. is 10.74.
That's a lot of difference.
I am sure that Ryan will eventually get his "bite" improved to accomplish 60-foot times like the Camaro, but for now, the horsepower for Ryan's Valiant would appear to be 480 if you used the mph of 127 at 2,800 pounds, but only 447 if you used the 10.74 e.t. figure.
That Wallace calculator is not dead-on reliable, but is good, I think, for making comparisons of your own car's performance.
Tilley's car (that I have seen in U-Tube videos) is a 4-speed, which may not e.t. as well as an automatic with a turbo. That would be one factor...
Just sayin'....