also was at 3550lbs. wet and my 1\8 mile times were 7.50 as well which was really good for an auto car footbraking.
I actually had some 28" bias MT's (no tubes) when i ran that. it only went through at 5600rpms at 114mph. switched to 26" radials and lost nothing even gaining 26lbs. of rotating weight so i think it could have run better with 26" bias with no tubes.
i had no belt on for the 11.89 run but used the short belt on an 11.98 just before and the following week at cecil 11.94 and 11.93 runs then mid day ran 11.91 with no belt. ecm got screwy in the evening when it cooled off and kept going into limpmode so i'm sure i could have gone quicker but couldn't get the issue worked out. never did figure out what was going on. it just cured itself.
not sure if you already have done this but datalog your IAT's. back then mine were up around 90degrees on a 50 degree day then so i got some heat shielding and put it under the intake to block the heat from the coolant hoses and around the CAI.
just did the same on the new combo and went from 11.26 to 10.99 with no other changes. it dropped my IAT's from 118-126degrees peak down to 80-85 degrees peak on a 65 gedree day. if i could ever get them to ambient temp i could probably run 10.60's or quicker add a trans brake and

already had a 1.46 60' just footbraking using the ebrake on that 10.91 run