i ran high 11s with a fairly mild 455, here is the combo as best i can remember it.
67 firebird fullinterior daily driver 3500 lbs
462 stock rods (arp bolts) and crank, weisco pistons
62 casting heads ported (guestamate flow 220-230 flow)
comp. magnum solid flat tappet cam 292 duration .550 lift
11.8:1 comp.
original torker with a 850 out of the box holley (jetted to combination)
1-3/4 headers..tried larger and it slowed down
3" exhaust mandrel bent w/ flowmasters, tailpipes
th400 10" tight converter
3.73:1 gears.
My brothers 68 bird convertable ran 12 flat with this combo as best i can remember
400 stock rods, crank and TRW pistons
same ported 62s( took them off my motor when I blew it up.)
Cam motion 290 duration (
[email protected] ) .540 lift solid cam
torker II manifold. not port matched. w/ 750 holley
1-3/4 headers w/3" mandrel bent exhaust, flowmasters no tailpipes
th350 w/ loose 10" converter 3800 IIRC
3:90 gears
The convertable was 3680 lbs left real hard out 60 my combo but made less MPH
sorry i rambled so long. Anyway both these combos were fairly inexpensive to build and maintain. Good luck and keep us posted.