circle track cam

Have you ever thought about running gas? Probably 40 - 50 ft lbs torque less, 1/2 fuel burn off to keep rear % up. I would bet your motor is 60- 70lbs heavier than a 604, it's 2 ft behind front wheel centerline, could put that amount right in front of rear axle. May be over 2450 total but would get you closer to a crate cars % for rear.
30 - 40 years ago I went from a aluminum flywheel and stock type pressure plate to a ram coupler, iirc 25lb weight difference, way snappier but a lot harder to control on the slick, I was faster with the heavy stuff because it was easier to hookup.
Guess I didn't give you any answers to you question but just throwing this out there, good luck!!!
Almost forgot, my magnum 5.9 eq headed b mod motor weighed 495- 500, a 602 weighs 435. I have never weighed a 604. La block is 8-10 lbs lighter than 5.9.