With the Mustang complete and awaiting the 2019 race season, I was getting a little stir crazy. I started a search and found an abandoned RX7 project, needing a complete build. The car came with Granny's 5.0 engine mounts and T5 crossmember, T5 transmission, Pro Ripper shifter, eBay clutch kit, flywheel, BBK shorty headers, slave cylinder conversion kit, new brake pads, and new shocks.

First thing's first, I snagged an Explorer 8.8 (31 spline 3.73 LSD) and shortened the axle using an extra passenger axle. I then swapped over the factory mounting points from the old rear end. With a 15x8, 5.5" BS wheel on 26x8 slicks, it fits like a glove.

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The engine "build" is simple as it gets; 5.0l from a 97 Explorer with 3 bar GT40 heads, Alex's Parts valve springs, mild Elgin cam by recommendation of a friend, Mustang oil pan, and Vic Jr. intake manifold.

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Cool project. Just curious... did you check the housing for alignment after the welding? Mine moved a fair amount after welding, and i'm curious who else is, or isn't straightening them.

 

Looks like a cool build. I was wondering about how you narrowed the 8.8. Did you swap axle tubes? I've seen the cut down method to narrow one but didn't notice any "seam" on yours. Maybe I missed it, anyway I always like to watch your builds, looking forward to seeing you put this one together.

 

I believe the housing width is even, the difference may be in the axle length itself.
Did you mig those or tig? Welds are impressive, great penetration, yet look great too.

 

I am curious too as I am getting nine inch ends put on a 8.8 and want to make sure the guy who does it makes sure that everything is straight.

Usually a person uses the short side axles and then you only need to cut one side of the housing tubes down if you are just using stock axles and housing ends. The best way is to remove the tube and cut then reinsert it and weld to the housing , the end is not touched this way.

You can weld! I sure wish I could, gotta try it one of these days. Love your projects, this one looks like fun too! Keep it up!

 

Awesome build, I've been looking at an rx7 also. Looks great so far.

 

I too did the explorer 8.8 swap and shortened the axle. Make sure you let us k ow how them 3.73 gears work out in loading the turbo.
- when I shortened mines I just braced it up with some 3” channel irons clamped to each tube lining up with the index markings an tig welded 180* of each other just a little at a time letting the welds cool. Once enough tacks were in place did 1 root pass and then a final stitch pass. No warping whats so ever

 

OP, sorry this is gone on such a tangent, i'll add just a bit more, and be done. I tig welded mine as well with the same root pass, cover pass technique. I found that welding spring perches, or suspension brackets on (welding 1/4-1/2 way around) moves it as much or more than shortening the one tube. I've narrowed 2 of these, the first, I never checked other than making sure the tube was straight with the existing tube when I welded it back together, for the second, I built a jig, and checked it before I started, and it was out. I tried to pull it back straight when welding the tubes to the center, and was able to move it just a little. I narrowed it like the first one by lining up the tubes, and of coarse it was still out, so I pressed it straight, and finally had to do a little more straightening after welding shock mounts, and perches on. Both of mine seemed to function fine, but I have to believe the first was crooked, thus my question.

As far as the 3.73's go, with a shortish tire (26-27") i'm sure they're not ideal for a light car, but if you follow Matt from Sloppy Mechanics, his Colorado had 3.73's and a fairly short tire, and it worked quite well.

 

Sorry OP for taking this thread sideways. Will follow for results

 

I didn't use a jig, just some angle iron, various squares, and strategic welding. I know there is a possibility it is not perfectly aligned. We shall see if there are any issues late down the road.

 

Nope, just shortened the long axle tube by 2-7/8", beveled both sides to 45* and left a 1/8" gap to ensure penetration. Thanks man!

 

MIG. Beveled both sides to 45* and left a 1/8" gap to help penetration. Thanks man!

 

Same process of alignment here as well. I was hoping to find a 3.55 LSD, if it proves to be too much gear, I have some 3.31s laying around.

 

No worries at all! I always appreciate thoughtful conversation, great points all around. I feel the 3.37s might be a bit much as well, 3.31s are sitting in the corner if so.

 

Mounted the plastic Summit seats that came with the car, hooked up the e brake, plumbed the rear brake line, installed the Granny’s motor mounts, buttoned up the engine, miscellaneous welding, installed the new Wilwood clutch MC, and snagged some new wheels and tires for the front. A new steel bearing retainer is currently holding up the engine and trans installation.

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Looks good so far... like the wheels, too

 

I say throw your Windsor engine in this from the stang and then do a grudge race against against that LS rx7 on here, that would be cool!

 

Thanks man, VERY limited on wheel selection with this goofy 4x110 pattern.

 

Haha Adam’s car is sweet, no doubt there.
I’m hoping to meet up with my buddy Reiners one day and get spanked by his SBE Windsor.

 

I have not seen anything from Tony on here or YB for a while. Is he still running his white foxbody? Last I heard about him was that he did not seem to happy with his twin setup, but that was a while ago.