It's cool, thanks. Once hardened the IRS and stock diff is supposed good for 10s with a V8 which, is about where we'll be so we'll probably just go that route.

I am; however, looking into regearing the unit so we an run a shorter tire.

Isn't the best thing to regear the diff numerically higher, run the tallest & widest tire possible, nearing redline in 4th gear at the expected trap speed? Leaving nothing on the table.

Or I guess with enough power it might be better to near redline in 3rd at the trap speed. Right?

My line of thinking, you don't want to waste time shifting right before you finish. And it's best to use the gearing to the cars advantage, up until you make enough power to waste the short gearing. But I don't think we're in that range.

The problem is that the approrpiate sized tire for our gearing presents fitment problems; it's very borderline. When expanding it might rub up into the wheel well. It probably doesn't matter for dragging, but taller gearing and shorter tire means less rotational mass (smaller tire). I'm only entertaining the idea because I have to buy wheels and tires anyway.

What ratio do you have now?

4.10

We'd have to run something close to a 28" tire to take advantage of the power, winding out to redline and trapping around 130. Which is all fine, except a 28" tire is a damn snug fit, and if it's a race slick it'll probably expand into the well, Which is non-ideal. :smack: Also, I'd prefer the look of a somewhat smaller tire.

You know real world and paper specs don't always match. You have a 4.10 use it. It's a good starting ratio and I'm thinking ( not always a good thing ) it could work out good for you. Stick your 26 inch tire on there and let rip. You are going to have wheel spin no mater what you do and that will screw up any paper specs you come up with.:bigthumbsup:

Drop, Disassemble, Clean IRS
 

Hey kiddies, picture time. While I'm low on time/cash resources (temporary) to kick this project into high gear, we do what we can to keep it moving.

Death Cult and I droppped, dissasembled and cleaned the IRS last week. Here tis:

Freshly dropped:




Disassembling, Cleaning

I agree with Glen. I think the 4.10 will be close to ideal for the engine combo you have now. Also know that I went 10.45 at 128 in the Chevelle on a 26x8.5x14 tire so I think you can get that car to hook up on a 9 or 9.5 inch tire. Remember when we test fit my Cobra tires on it? They were 26x9.5x17 but on a 8 inch rim they are closer to 27 inches tall and they fit perfect. I launch the Cobra at 6000 rpms on those and they hook with my 3650lbs. so I think they will hook good in a lighter car with a lower rpm launch. If you want to use my tires before buying some just let me know. That way you can see how much tire you'll need and if the gearing will need to be changed.

Thanks Ron, I'm grateful for all your help.

My concern with the fitment of your tire would be how much it might expand under heavy acceleration. I rembember there beings something like maybe a 1/2 clearance. No way I'd trust something like a wrinkle wall slick of that approximate size, but maybe a DR or, basic (?) slick, might not expand too much. What do you think?


Second question. Might I be able to bring out the pumpkin to you and you could pop it open and take a look at the gears and maybe the LSD to evaluate it's condition. I figure while things are totally apart, it makes some sense to evaluate their condition.

Invite me when you guys go through the diff. That's the one thing I've yet to learn.