Ask the Ford guys. I would guess since 289 and 302 are the same block, 63-86?:smack:(I really don't know Fords like Glenn)

As far as I know, yes, but something to check. I'll put this in the questions section. I see this car being run at street legal, TNT, private track days and *maybe* PSCA.

We could always get some cut-outs. That way we can go either way. We can just get the cheap manual ones, not the electronic ones.

Open headers? You wimps. Why not zoomies? I can cut two slots in the hood for each row of tubes.

No I'm not kidding.

That'll match the Rebel Flag theme nicely. . . :sm_up_there:

No but it will add to the Amerijap car confusion... and horsepower.

BUMP


So, as long as you guys can wait until I get back from this deployment (mid-November) AND I can find an IRS for a decent price for the Mustang - the rear-end from her is definitely available for the project...

Don't go to an IRS on your car. You can make your car handle just as good with the solid axle and it will be a lot stronger.

Ben, if you want to upgrade to a solid 8.8 I can check with GTR and see if they have one laying around.

If you could get a quote, I'd be curious. Currently I have the stock IRS fully dropped and disassembled. I still have a hankering to harden it with Delrin/UVHM/Solid mounts and bushings and use it.

I just checked and they don't have any.

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.

That's it, then you're all done? :smack:

They fit fine and even if they grow they won't rub. :thumbs_up: However, with the short sidewall on them I doubt they will grow much.

We can take a look at the rearend anytime. All we need to check for is the wear pattern on the ring and pinion and check the bearings and race for pitting and wear. As for checking the limited slip it all depends on what type Mazda used. Did they use a clutch style?

Thy had both in that era and I "believe" ours is a clutch type.

What is the difference betweent he Tbird and Explorer 8.8 Diffs?

It looks like a guy is building a setup to allow mounting an Explorer sourced 8.8 into the stock IRS. Some fab required for axles, but otherwise, looks like a pretty slick solution.

http://www.v8rx7forum.com/v8-rx7-tec...ar-v2-0-a.html

I'm new here but this sort of project is right up my alley.

As for the diff selection, if your going to be using a blown 302 with 500hp or less there is no point in the time, energy, or cost of doing a solid axle swap. I don't know what model FC you have but ill assume its a GTU based on the 5 lug hubs, LSD, and 4.11. I wouldn't trust the n/a diff much farther than you can throw it. It'll probably hold up... for a bit. I would go with a TII rear, these little diffs have proven to hold up reliably with 600+hp launches(im talking about SBC power here). Hell they actually swap the TII rears into 93+ FD's. If one does happen to grenade they are on ebay all the time for ~$200. As for gearing your pretty much limited to 3.9, 4.11, or 4.33 as far as readily available ratio's go.

Another option you might want to look into is a guy in the 7 community was building subframes to fit an IRS dana 36/44 out of a C4 into the FD and FC. I'll look to see if i can find his page/thread(been a few years since i've heard anything) but this will enable you to keep the IRS and open up all kinds of gearing options. The other, more common way to go would be the cobra 8.8 irs swap. there's guys that make subframes already and you can pick up the complete 8.8 setup for about $1k.

If you do decide to go live axle the most reasonable method would be a '96+ explorer (all over junk yards in good condition for ~$250). the explorers have the higher spline count axles and are stronger than most of the 8.8 ranger and mustang rears. You'd want '96+ because of the disk brakes. There's no reason to go with a 9" as far as i can tell based on projected power. Plus if your stressing over any slight lateral location of the pinion on the 8.8. the 9" pinion is around 2" to the right.

I personally have something against live axle 7's tho, its a good handling car. If you just want a good power to weight with a live axle for the strip there's always the fox body.

Anyway, I'm about a year late for this party so the decision might have already been made. But still, i'd love to help out. Anything you need to know about the FC just let me know.

Hot damn! Consider yourself volunteered. My current thinking is the 8.8 IRS setup, but I thought total cost pushed $2k, by the time you were done with the half shaft work etc.? I seriously considered the TII diff as it does seem to be strong, but we'll be talking a torque monster on sticky rubber and it seems 450WHP is more the real world break point. At least that's what I found. :huh: Putting the TII is tribial and cheap compared to the 8.8" . . . that's for damn sure.

BTW, This project was put on a kind of back burner as my wife left her gig about a year ago now and we decided now is a great time to start a small business. It's working out ok, and all the foot work is done on that, but still hemorrhaging play money. Nevertheless, I'm hell bent to keep pushing on this as I can and one the play money comes back on line, it'll be totally focused on this project.

Considering the scope of this project, I'd assume $200(cost of a TII diff, less if you can find one in a yard) isn't going to break it. I'm not suggesting throwing money around but if a $200 experiment could save you $1500 in fab work, it might be worth it. That's not so say if the TII rear doesn't work out you couldn't still splurge on a built 8.8.

Depending on your fab skills you might be able to throw together a budget dana 44/8.8 conversion on the cheap.

I feel you on the play money, or lack thereof. >.<

It's a good point. If a TII could even work for a while, it might substantially improve our timeline to getting the project on the road for real.

For carb cars... yes :)

I got the hubs apart, front bearings packed. The studs not the same front to rear. The front studs have a longer spline area, and overall length.

Thanks Paul. :thumbs_up:

I have the bearings going together now. Are we using the backing plates/dust shields? I would assume not, being a lighter is better thinker. But before I press the hubs together, they would need to go on.

I would say not as well.

Nope.

Ok, I am a dork when it comes to posting picks in the thread. I don't know how to post them large, like normal people do.

I have a few here that need captions, so I will number my comments.

#1: Safety glasses make me look even cooler !

#2: My 30 ton press

#3: I cut a relief into the bearing race, and then use a chisel to split it. Making
it easier to remove.

#4: The cut in the race.

#5: The cut in my face ! I took one for the team ! Hardened steel can be
brittle, and chip. Sending bits into your nose. Second time in 25 years I
did this to myself (last time left a chunk in my forearm that I can still
stick a magnet to). Next time I will put the safety nose guard on too !

I should have the hubs back to Ben Friday night.

Awesome! Too bad you didn't bleed near painting, we could have mixed it in. I'll give you a hands on photo lesson. Or maybe I should make a thread.