Rear end gear ratios

[7duce swinger]

I've been trying to perfect my 72 swinger and I'm trying to lick out gear ratios. I have a 31i with a small cam, 486"/486" and I believe its cut on a 109 lsa. Milled 360 heads, cant remember how much they were milled. Hedman longtube headers, air gap intake, 750 bt demon and torqstorm supercharger.
Trans is a cope racing 904 full manual reverse vb with a hughes 3500 stall. I did the 8.8 swap years ago but didnt update the gearing.

Would my setup benefit from 3.73 ratio or 4.30 gear ratio? I have a brand new set of 4.30 ring and pinion to throw in it or I can buy a 3.73 setup. As of right now it has a 3.27 ratio and limited slip, 31 spline axles etc. Its mainly going to be driven around town maybe a few rips on the backroads and strips.

 

[dano]

With the super charger maybe 3.55's considering the street use. When does the boost come on and when does it taper off?

 

[brian6pac]

I wouldn't go from 3.27 to 3.55 not enough of a change you probably wouldn't even feel it, 3.73 would be the min change I would do. 4.30 would be to steep for the highway.
I see U.S. Gear makes a 3.90 gear that would be fun on the street and still good for 60 mph.

 

[7duce swinger]

I wouldn't go from 3.27 to 3.55 not enough of a change you probably wouldn't even feel it, 3.73 would be the min change I would do. 4.30 would be to steep for the highway.
I see U.S. Gear makes a 3.90 gear that would be fun on the street and still good for 60 mph.

That's why I started with 3.73 lol. My saleen fox has 3.55 and it wasnt worth the change from the last gears it had.

Not worried at all about highway, might do 3.73 though. Just hate to do rear ends 3 times. My saleen I have to redo the gears because the 3.55 wasnt worth the money and not what I wanted out of it.

 

[7duce swinger]

With the super charger maybe 3.55's considering the street use. When does the boost come on and when does it taper off?

It's a centrifugal so it will make it around 3k and on up. Will make boost past what rpms I plan on spinning it. I am driving it with the blower disconnected and it's a slouch with 3.27s

 

[dano]

Oh yeah, 3500 stall....that would suck. 3.73 would probably be a dog too.