Over the winter I'm mini tubbing my Dart and will be buying a S60 to go in it. I already have the new tires and wheels for it, Weld 15 X 10 with 3.5" bs and MT 325/50 ET Street Radials. The 8 3/4 I'm replacing had 4.30 gears in it, I'm considering going with 4.10 in the 60. This is in a street/strip 3300# 69 Dart with a pump gas 408. It's in the 550 hp range.

The 408 only has 10 passes on it including the one that shucked the ring gear teeth. The only clean pass it's made it ran (1/8) 6.61 @ 102.24 with a 1.41 60'.

I had the 340 in it when I went from 3.91 to 4.30 and it only picked up .06 and all that was in 60'. The 340 ran a best of 7.24 with the 4.30.

What do you guys think, 4.10 or 4.30? It doesn't get driven a lot, but I think 4.10s with the 28" rear tire would not be a bad drive.

Thanks, Justin

When does the engine make peak power (hp and tq?) If it' a race car first, gear so it's about 100rpm higher than HP peak at the stripe. All the stroker equipped cars I had a hand in run 3.23 or 3.54 gearing. The engines like to pull against a load...lol. but if you're wanting to go as quick as you can, have the engine dyno'd when it's done (not a computer simulation...) and then pick a convertor and gear package for it.

The engine is already in the car. The only dyno I have is the time slip and the seat of my pants .

4.30

That's what I run, but I go 1/4 mile racing, not 1/8th mile.
With 28" tires and a good converter, I'm trapping 6400rpm at the stripe at 120mph, shifting at 6200.

Did you weld it in place?

I'd rather know if this is a race car. If you dont want to pull it stick 4.10s in it. That would be my guess.

I vote for 4.10 gears. That is what I put in my car. Plus, when I add more power in the near future I will not be over geared. And, I have the option of going to a taller tire since I streteched my wheel openings.

I haul it to the track, the closest one is about 1 1/2 hour drive. I like to drive it to town and to work on occasion.

Justin, what converter do you have and where do you shift? You know my old Dart , with the stroker I was shifting at 64-6500 and trapping at 6600, this with an 8" race verter that flashed to 5200. I ran a 4.10 gear with it and a 30" tire. Best 60 ft was 1.43, best 1/8 mi was 6.59 @ 104, best 1/4 was 10.45 @ 127.

4.10

ive got 4;10 in mine, id like to try 30's just to see if it makes a difference

Ken glad to see you here
I run 4.30s 11.5 29.5 w hoosiers shift 6600 through traps 6900 even with low gear in trans now
ran those gears with 410ci and the new 418ci
i would do 4.30s if you don't do alot of cruising .
don

i run 4.30's in my stroker and it is a street car. hehehehehehehehe

It's only 5% difference, and the 4.10 is safer.

I would run a 3.91 or 3.73 gear. I ran 4.30's in the cuda and changed to 3.91 and ran faster. The stroked small blocks have a ton of low end power and dont need the tall gear. The cudas best 60' was a 1.36 with a best of 9.98 @ 134. running the MT street radial. I wanted to try the 3.73 gear but didnt get a chance to. Theres no need to wind up that long arm small block if you dont need to. Trust me, you wont be sorry. For a street strip car stay with the 3.91 and 28" tire....Phill

maybe I should try a different gear I am running 4.88 with a 32x14 M/T

We went fron 4.30 to 3.91 to 3.55 on our 414, race only mud truck, the more load on the engine the faster we go

From your previous runs try to gear it so you go
through the traps at 10% above peak HP.... I run a
4.56 with a 31" tire and trap at about 8200 at 150 MPH
set you stall for around peak torque or slightly better