What gear should I run with this Set up?

[deputycrawford]

I have mentioned many time s before that I have a 383 bored .040 over with 906 heads that have been milled .050 and ported. I have 9.35 to 1 compression, a RPM intake that has been ported and a Mighty Demon 750 carb. My cam is a custom Engle solid with .560 lift intake and .575 exhaust. my duration at .050 is 245 intake and 253 exhaust. I have a 3500 stall, 9 1/2 inch Dynamic converter and an A & A trans with most of the fixings. I am also running a 4.10 gear out back.

I have a vibration that comes in around 70 mph to 90 mph. I am starting to think it is the center section gears chattering. My point is that I will change the center section out for my spare 3.23 and see if the vibration stops. If it does I will be rebuilding my 4.10 again. Should I opt for the 4.30 gear to help the cam. I will be driving it on the track when I can and don't mind the extra rpm in town. I just want this car in the mid 12's with no problem. I can always change the pig for out of town trips. What gear would anyone suggust?

[jg68]

I have mentioned many time s before that I have a 383 bored .040 over with 906 heads that have been milled .050 and ported. I have 9.35 to 1 compression, a RPM intake that has been ported and a Mighty Demon 750 carb. My cam is a custom Engle solid with .560 lift intake and .575 exhaust. my duration at .050 is 245 intake and 253 exhaust. I have a 3500 stall, 9 1/2 inch Dynamic converter and an A & A trans with most of the fixings. I am also running a 4.10 gear out back.

I have a vibration that comes in around 70 mph to 90 mph. I am starting to think it is the center section gears chattering. My point is that I will change the center section out for my spare 3.23 and see if the vibration stops. If it does I will be rebuilding my 4.10 again. Should I opt for the 4.30 gear to help the cam. I will be driving it on the track when I can and don't mind the extra rpm in town. I just want this car in the mid 12's with no problem. I can always change the pig for out of town trips. What gear would anyone suggust?

I ran 411s in my duster, it had a very mild 383, stock bottom end, it made it through the 1/4 with 26/8 slicks, so with 28s it would have run much better, so i'll say you should go with the 430s for sure if your running at least a 28" tire, better yet, 456s with a 29" tire

[deputycrawford]

I did forget to mention that I am running 28 inch M/T drag radials. I know that makes a difference.

[jg68]

I would use a 4.30 with that size tire with a 383 & a solid cam that size

[firefighter3931]

I would use a 4.30 with that size tire with a 383 & a solid cam that size

The 4.30's should put you right around 6500 through the traps with the 28in tire. That cam should pull pretty good well into the mid 6k range in a 383ci combo. 


Ron