I'm wondering where to look for a drag race ring and pinion for a 4 speed small block a body. Im looking for 4.86 gear this is in a 10 second 4 speed small block car. I see street gears but haven't found anything else. Will the typical street gear hold up.

What rear end are you running?

Running an 8 3/4.

Maybe, but not likely. I don’t think you can even buy a pro gear for the 8.75 any more. Hard to find many ratios in the pro gear for the D60 either.

If you have a good clutch you might get lucky and get 50-75 runs out of the street gears. Maybe. Bad clutch tune up...not many.

May be time to look into the 9 inch. I suspect that in 10 years or less the only pro gears you can buy will be for the 9.

If you make your car hook up well it will break the 8 3/4, especially with mild street and strip motor
Been there done that way to many times
Stop now and sell the 8 3/4 and buy a Dana 60 with a posi and 35 spline street axles, not race axles.
Call Cass at Dr. Diff. at 406-883-4772 and tell him Cab said to call to place your order.
He will have a bunch of questions on how you want your rear end built like width, spring pad placements, which brakes you want and so on. He is good to work with and good on prices and very smart on rear ends

cass / dr diff is an amazing guy to work with. he is sooooo good. I honestly have 40 emails back and fourth with him about dana 60 stuff. In the end he got me all sorted out and got me the parts i needed to get the car moving again. I am getting ready to do another d60 and WILL be using him again.

Its a narrowed rear coil over ladder bar. So I will have to start over.

Everybody is convinced that an 8-3/4 will self destruct behind anything hotter than stock. I’d admit that behind a clutch isn’t the ideal spot for one, but it’s an A-body, so we’re not throwing a lot of weight at it. You mentioned that it’s already narrowed, and if it’s backbraced then it’s not gonna flex much. I bet if you were to put your parts into a Yukon Nodular case, it would last quite a while even with standard gears. I throw 3880lbs at mine; 60’ in 1.54.... I just stripped my 742 case down, it has had the same 4.10 street gear set in it for a few years now. They looked just fine. Not saying a Dana wouldn’t be an upgrade, but if you haven’t broken it yet, what makes everyone think you suddenly will now? Your money.... Cass is the right guy to be dealing with, that’s for sure.

I launch at 4200 rpm and sixty ft 1.50s and it looks and feels like an auto. Reason I was asking is its under geared with 4.56 thats why I was looking for 4.86 . Im not sure what clutch or type of ring and pinion as I bought the car from a person that had it sored for a decade and not much info.

Dana the best way to go however if you rem finish and cryogenic the gears they will last longer.

I believe that all the new 8.75 gears come out of Italy, India and China. Your best bet is an OEM Zoom/Richmond. With a street tire, lots of spin and a soft loc up clutch. , should be able to get a summer out of them. Red Line gear oil for rears has the best slap formula. Many Ford 8.8 rear racers swear by it.

Drag racing is hard on driveline parts, especially with a 4 speed. Why waste time and money on anything less than the strongest parts for the application? I would switch to something where you can get pro gears like a 60 or a 9, and be done with it. It's more $ now, but cheaper in the long run.

I agree....... and will add...... they make pro gears for a reason.

My friend runs a stick in a 3300-3400lb(depends on the class) Stocker.
It has the fancy easy-on-parts clutch.
Rear gears are still fairly frequently replaced........ pro gears, MW 12 bolt.

Are there pro gears for the D60 currently in production? With economies of scale, I think the 9" is the only reliable source for 4 spd longevity.

No radials, small slick for a controlled spin, aluminum flywheel, clutch tamer. Should be a fun ride.

Geez I was just looking for 4.86 ring an pinion, now I need to replace my rearend. cheaper for me to go auto.

have you thought of buying and running a shorter tire to steepen up the ratio in all gears instead of changing the rear gears?
4.89 divided into 4.56 equals .9325 or 6 3/4 % difference in the two ratios. 27 inch tall compared to 26 inch tall equals which is .9629 or 3 3/4 % difference in circumference. My point is you can achieve your goals more than one way.
I use to help a guy who later become a good drag racing friend on a 1970 4 speed Duster with a stock 1970 T.A 340 motor in it minus the six pack, he raced it a lot on the street and later at the track, he broke a bunch of 8 3/4 rear end parts including the last time it exploded the clutch type posi unit blowing pieces out of the back of the rear end housing into the gas tank It had a set of 5.38 or 5.13 gears in it when that happened, he switch to a Dana 60 with 5.57 and 35 spline axles with a clutch type Dana 60 posi and never had to work on the rear again
Good hooking SB A motor 4 speed cars are hard on drive train parts, 727 and 904 are not
You can learn from others or the hard way, it is your choice

I agree with Cab..... and that last line, btdt... just shy of upgrading to 35 spline axles, which of course requires a new spool, we cut the cord and went S-60 (Strange version of Dana-60). Sometimes we do with what we have, but sure end up spending a lot of money twice.