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View Full Version : Which final gear for 2nd car and weekend racer?



yldouright
07-11-2018, 07:14 PM
I heard there were three options 3.35, 3.55 and 3.73. Which came stock on which SVO and how do you know what's in the rear without opening it?

Laredo
07-11-2018, 08:36 PM
No, No, and Yes

1984 only - 2nd gear 2.37, rear 3.45, total ratio 8.18
1985/1986 - 2nd gear 2.14, rear 3.73, total ratio 7.98

There should be a tag on the rear diff cover. If not, raise rear, mark your rear tire, put trans in nuetral. **Be safe, wheel chocks and jack stands**
Count driveshaft rotations / 1 wheel rotation.
Approx 3-1/2 revs = 3.45 gears, approx 3-3/4 revs = 3.73 gears

Reference FAQ section
http://www.svoca.com/FAQ/

For short course Auto-X I run the '87 Turbo Coupe trans w/2.34 2nd gear w/3.73 = 8.73 total ratio.
What kind of "weekend" racing are you planning?

yldouright
07-11-2018, 09:00 PM
@Laredo
Thanks, if we can tune an SVO to make 300whp, a 3.73 would be under driven @5800rpm. I think I remember reading Fox Cobras had a 3.08 rear, does anyone know its total ratio? Ideally, a 300whp SVO that is still polite when grocery shopping with a 7.0 total ratio seems like a plan. Does anyone have a spare 3.25 rear? Is there one in any 8.8 rears that you guys can think of?

svono50
07-12-2018, 01:00 PM
I have fun with my 4.10's in my 86, although I am only ~270rwhp ;) My choice for that gear ratio is that they were available just as I was swapping from the stock 7.5 to an 8.8 that had 3.73's that someone I knew just had to have. Since I was drag racing at the time the 4.10's were a natural setup and did get me 1.8 60' times on slicks. Now that I auto-x and HPDE, they actually work pretty well too, so I wouldn't hesitate to recommend over the stock 3.73's in an 85.5/86. I think they may be a bit much in an 84/85 though.

Now, I did have an 84 T5 out an SVO in my former 80 Mustang that had a NA 2.3L. When I crunched my 2.73 gears in that car, I moved over to a 3.27 ratio set. That really woke up the little 2.3L and worked great with the 84 T5's gear ratios. In pure stock form that car went 18.5's @ 73mph, when I had things dialed in with the engine/tranny/gears it was going 15.4's @ 85mph. Not too shabby for a NA 2.3L back in the day.

yldouright
07-12-2018, 01:19 PM
Not too shabby for a NA 2.3L back in the day.Those are some good numbers for sure on a Lima. If you can remember what you did, you would be the guy to consult on getting the SVO to make 150whp without the snail.

@Laredo
I've only been to Sarasota and NJ Sports but I plan on others. I'd be looking at SVRA track events and the like. Straight line runs that end before they even start don't excite me :)