swapping 5speed to Auto for race purposes only

P/W is Power to Weight Ratio . I used 400/3400=.1176
MaMopar compiled a chart back in the 60s which translates P/Ws for 9 to 16 second SuperStock cars. They say it's pretty accurate, for SuperStockers.
I use it on streeters by adding between .5 and 1.0 second for street suspension and street gears, and street tires, etc.
And I use it backwards to calculate power needed to achieve an ET with street suspension. It's not always accurate when used that way, but it gives you an idea of what to expect from a given combo, with in +/- about a half second.

Your avatar looks like a 70/71 Swinger; how did you get it up to 3660?
Mine scaled 3330 back in 1971, with 18 year old 130 pound me in it, so 3200 for the car alone . That was a 340-4speed 8.75 with P/S and P/B, stock Rallys and E70-14s,lol, and a bithin 8-track stereo, cranking out the Rolling Stones.
What? Subwoofer? No that was before them, Just two 6x9 triaxles, and a pair of 5s in the doors, state of the art in 74........

If your car truley scales that heavy, then your P/W would be 400/3660 =.1093 and a SuperStocker might go 11.9 with that. Your Caltracks will help you with that, and so would the 4.10s and M/Ts.
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My car was 3650 and went 12.9/106 with a 4 speed, 3.55s and street tires. The engine was a 367 with OOTB Eddies and a [email protected] cam . The 106 says P/W was .09236 and a SS suspension shoulda gone about 12.5. So that combo was not far off the mark.
BTW, that P/W of .09236 translates to 339hp