i say try both if you can. i have a all steel 73 dodge dart that should weigh around 3500 pounds with me in it.i weigh around 310 pounds my self.I had a set of 4.10 gears in my 742 case 8-3/4 and on my 5 pass i blew up the 4.10 gears. they was a brand new set of richmond 4.10 that were put in the car before i bought it.So i put a set of used 4.30 gears in my dart. i owned them once before.i have a engine close too yours that i run on 93 pump gas except mine has
bowl ported Indy ez heads that are so posed to flow 310-315 at 600 lift
i have wisco flat tops that is right at 11.1.1 compression
comp solid roller that is 264 at 0.050 and 634 lift with my 1.6 roller rockers
i am running a tunnel ram with 2 carter comp 750 carbs soon to install some Holley 650 dp with some pro form main body's.
dynamic 9.5 inch converter that stall around 4500 rpm
m/t 275/60/15 et street drag radials
my best pass with the 4.10 was a 10.67 at 125.00 in the 1/4 before i blew up the 4.10 i never did get to do any tuning. ti was a nice cool day that day. i only got to try out the 4.30 one time last year and it was 96 97 degrees at 12:00 am that weekend. was a very bad nite for racing.to hot and humid.only was running 1/8 that nite which i think my best pass that nite was a 7.03 at 98/99 mph. my best pass on the cool day was a 6.88 at 100.8 mph. here is a pic of my 4.10 gears. good luck with your car and post some pics of it when you get it running.thanks Mopar65