I am building my '85 T/A in "Pro-touring" style. Rear tires are going to be 335/25/19's (Or something like that, whatever it is that the new ZR-1 is using for rear tires.) I know I will have to move a lot of things around to get these to fit (Something like a 13" wide wheel) I will be using QA1 coilovers, most likely. This will be a 900+hp car and I will need something strong. I am already comitted to using a 12 bolt or S-60 rear axle (Narrowed, of course) and would like it to handle very well. I am building it to compete in the silver state classic and possibly the hot rod power tour.
I have seen some mini-tub projects and they look like they went well, but with something that wide, I think I am in "full-tub" territory.
Any advice would be much appreciated!
Thanks!

 

i have a 18x12" wheel and a 335/30/18. The wheel measures 13" in width overall, the tire 13.5 sectional.

You would be looking at a 11.5 to 12.5" rim, no wider, that tire should fit with no issues on a 12" rim.

I have the outside of the tire about 3/8 to 1/2" inboard from the outside of the fender, and i have 3/4" of clearance to the inside of my minitub. I can fit a 345/30/18 with no problems. I dont see why you would have any issues either.

Im using a stock width 9" moser rear. Im using a wheel with 8.5" of backspacing. I cut the sheetmetal out of the wheel well back to 9 5/8" from the axle face, then rebuild the side of the frame with a piece of 11ga sheetmetal, giving me 9.5" from the rotor fase to the new frame rail.

The coil-overs will work with this setup, thats what im using. I dont see any reason to use a narrowed rear, unless you have a specific wheel in mind that is only available is a certain offset.

I assume you are looking to keep the stock style suspension?

I did have to have a set of offset rear lower control arms made, Spohn did it, and i think he still has the plans for them if you go that route. They would work with a 18" or larger wheel. Not sure if they would hold 900 horsepower though, unless you are talking out your *** with the number.

-Phil

 

I have a full tub, back halved car. I have 15" wide rims with 5.5" of backspace and tires have 14" across the tread. They're also 32" tall. My diff from axle flange to axle flange is 45". Factory length is around 63".

Because the tires you want to use are roughly the same height as a factory tire of 26", your inner fender modification don't need to be as extreme as other tire swaps but you're still very limited to how much tire can be stuffed under the fender. The typical "mini tub" of a third gen is mainly to put a taller tire under the fenders. I was able to stuff a 29.5 x 10.5 slick mounted on a 10" rim under the factory fenders with only minimal inner fender modifications. Those were 13.1" across the section. I needed a bit more fender modifications because of the height.

With the shorter tire, you don't have to worry as much at the front or rear of the wheel well. Cutting off the bump stop will give a bit more inner clearance but you can't move the inner part of the inner fender in any more than it already is since that's part of the framework. Cutting off the side of the spring pocket and plating over it will give a little more additional room.

You don't need a narrowed diff. You just need rims with the proper amount of backspacing to keep the tires centered under the fenders. A narrowed diff will just require rims with a lot less backspace like mine.

Those skinny sidewall tires you want to use will not hold 900 HP. They only have 2.2" of sidewall.

 

LOL, no I'm not talking out my A$$! I am in the process of building a Twin-turbo 383 for the car. Weak point is going to be my "Texas 6-speed" built T-56. I would be really happy if I can get them to fit without cutting out the rear frame rails. (Dont mind boxing them, though) I can build some solid LCA's, thats no problem. I'm a member of a jeep club and we are always building control arms with 3/4" heim joints.
I do want a slightly larger backspace than stock. wheels will probably be fiske, but havent made up my mind yet. I was told "Get the wheels and tires and then order your axle to fit" I'm guessing thats good advice? I'm also going to need some massive stopping power and havent decided what to put up front as far as wheel/tire size. I will be ordering a tubular k-member (Most likely with the coilover conversion) but havent decided which brand to use.
I'm really picky with my cars and if it dosent dyno at 900 RWHP, I will tear it down and start over (Though if it was close, say 889rwhp, I could live with it. not THAT picky!). I dont mean to come off sounding like an A$$ or a bragart, and money IS an object. (More money = more time.)
I will get a set of drag radials for the rear, BTW.

//<86TA>\\ Got pics of yours?
Thanks!!!

 

i didnt mean to offend with my comment about your power numbers, it just that numbers get through around here all the time by people who dont have a clue.

You dont have to cut the frame reail out, but you have the cut one side of it completely off, then box it back in.

So you can see what i mean, if you pull the carpet out in the back of the car so you can see the shock mounts. the outside edge of the mount pocket is about 9 3/8 from the axle flange, I cut right at the top of that edge and hammered it to a more straight position, giving be 9 5/8. That will give you an idea of where you have to cut.

I will have to find my thread, its in the fab board i think, it has pics. I also have another one with the widened interior that i've built to cover the tubs.

 

Too many people see vehicles in magazines or on automotive TV shows. They think building something like this with little to no knowledge about what really needs be done is cheap and easy. typically a job like this is done by someone with a lot of skills or it's done by a custom car shop with unlimited tools and resources.

Although a 900 HP small block is possible with a power adder such as turbos, very few are streetable.

It's kind of a catch 22 situation. If you have enough fabrication skills to tackle such a job, you wouldn't be asking. If you're asking on exactly how to do it, it shows you don't have enough knowledge on exactly what should be done. It's the same as doing some weird engine swap. Anything can be made to work with anything else. It just takes time and money to make it work. You already know what you want to do. Fabricate and modify to make it work or take criticism from TGO members on what's recommended to work best.

I researched for about a year before doing my back half but I never asked anyone on how to exactly do it. I did ask more technical questions like where the best position to put the chassis 4-link brackets etc.

 

No offense taken. I have built several street rods and high horsepower cars (My RS is my highest to date at 590+hp) A friend of mine builds turbo motors, so the motor is no problem. As far as the fab skills and asking how to do it: I always ask a lot of questions to see what kind of mistakes others had learned along the way, and what kind of tricks as well. I did build my own 4-link for my mini truck several years ago. (I also owned my own custom shop back in the 90's, though, not doing this kind of stuff, exactly.) If you ask anyone they will always say "... I would have done this differently, if I had it to do all over again..." My LS-1/T-56 swap was a lot like that. (When I did it, no company was making swap parts.)

//<86TA>\\; I think I remember seeing your thread when you did the mini-tub. As I remember, you were concerned about mounting the coilovers in (Or near.) the factory shock mount locations. How'd that work out?

Stephen 87 IROC; I know what you mean about the streetable issue. My RS will not idle on the street very well. Kind of a tap dance on the throttle to keep it running.
I drove my RS 400 miles in two years, and thats the most I have ever driven any of my radical street cars. Even my "Daily driver - capable" IROC only gets driven around 30 miles per month. (It is almost 15 miles to our local show and shine shows. They have them weekly, but I only go once a month.)
I just dont drive them.
Thanks for the advice and I welcome the criticism! LOL.

 

Its working out fine, the rear kit come with a reinforcemetn plate for the spring pocket that takes the load off the sheetmetal upper shock mount. The only thing i did was make a wider mount for the lower mount so i could move the shock a little bit to gain some clearance from my sway bar. I think it was more of an issue with the bar itself that the coilover, from other pics i've seen, the bar that i have doesnt seem to be bent as much on the ends and i caused some interference. I have since swapped to a different bar.

The panhard mounts are really close to the wheel too. I had to clearance the axle mount just slightly because its sitting inside the wheel. Passengerside was close, but didnt need any work.

 

I just drove my 1003 hp twin turbo car on my 7th Hot Rod Power Tour long haul, It has AC and idles smooth at 800rpm, had over 15,000 mile on this engine now. A 1000hp turbo engine is more street friendly than a 450hp na sbc.

 

Thats what I've heard. The engine I am building is built to spec's similar to nelson racings 1500hp twin-turbo. (But smaller displacement and smaller turbo's)

 

I remember! I really like how yours turned out and the modifications to the frame looked really clean.
Where'd you get the kit again?

 

what kit?

i made it all from scratch, unless you are talking coil-overs, those are Spohn

 

I was talking about the coilovers. You said the rear kit came with a reinforcement plate....

Spohn, huh? Do you happen to remember the part #? I was thinking QA1 Double-adjustable, but I'm not completely sold on those.

 

http://www.spohn.net/shop/1982-1992-...oil-Over-Kits/

 

LOL, I guess I will be getting QA1's after all! They are one and the same! I guess I will be getting the double adjustable coilovers as the price is pretty reasonable.
Thanks!!