you could also have some other issue such as fuel delivery, ignition, etc. Lots of things can kill the power.
Since the ignition and fuel delivery were good for 13.0@109 before, it’s unlikely they’re the problem now.
And that was with the cam going away.
109 was enough speed to run well under 12.50.
A converter swap alone would have had the OP reaching the performance goals, although it wouldn’t have done much for the drivability.
Since the OP states the lift on the old cam was close to the new cam, the old cam was probably a MP509 cam........ which would def make more HP up top than the XE275HL(248@.050 vs 231@.050).
The Moroso chart shows difference in speed between 109mph vs 101mph, at around 3600lbs to be roughly 85hp.
The question at this point is, how much of that speed gap would be made up by just having the valvetrain be stable for the full 1/4 mile run?
