A starting line ratio of 9/1 is very close to optimum, maybe a tad high. 4.88 x 1.8 would be 8.78, not too much unless you have very large stroker motor. I get away with 11.17 due to using a soft launch (low rpm) and 33 inch tall tires.
I’m interested in what you are trying to say here. It’s a 500ci Indy maxx aluminum block, just 4.15 stroke.
In my the case, i have 549 cubes, 52% on the front, 2.45 low gear torqueflite, 4.56 rear gears, 30 inch ladderbars, 106 inch wheelbase.
Converter flashes to 6200, shift 7600 rpm or more. The best 60 ft so far is 1.224, and that was with a throttle controller.
The throttle controller keeps throttle at about 10 percent open ,or 3800 rpm till trans brake is released, then takes about .10 to fully open, resulting in a very soft hit and no violent hit on the wheeliebars. This was my first shot at a low rpm launch, but gave me the best 60ft ever.
In your case, with a 1.800 first gear you could leave at 4000, to 4500rpm, run a 4.56 to 4.88 rear gear, and have a KILLER consistant car. The 4.56 might be my choice, because it will be deep enough for near best performance, yet allow your shift to happen further down track for great consistancy, and you stll will be able to run 1/4 mile if desired.
Good double adjustable shocks are important . Consider that an 8.0 starting line ratio multiplies engine torque EIGHT times after the converter doubles it! 700 ft lbs becomes 11, 200 ft lbs at the axles, and. Your springs and shocks have to tame that, and apply it smoothly .
That car weighed 3450 lbs. with me in it with a full tank of gas in the stock gas tank
15x33x15 inch Goodyear slicks on 15 inch wide rear rims