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Mini Tubs on a 65 Fastback?

33K views 33 replies 14 participants last post by  fastbacker 
#1 ·
I've got a 65 fastback that currently has 245/40/17's on the rear. Nowhere near enough meat for 652bhp/620tq-6000rmp. I would love to get 295 - 315's to fit. I'm thinking the only shot is with mini tubs and completely rolled lip. I definitely don't want to flare it but may land up doing a subtle custom 1" flare if needed.

The car has the Griggs Racing GR350 suspension so there's no leafsprings. The GR350 suspension does use the rear of the frame rails so they can't be moved. If I move the inner wheelhouses to the frame rail, I only gain about 1 - 1 1/2".

Couple of questions:

1. Anyone know if I can fit a 295+ without flaring?
2. Will the interior side panels need to be altered (I have a Shelby GT350 seat delete)

Thanks-
Craig Backer
 
#7 ·
jestang said:
What rim size and backspacing are you running to fit 255s on the rear?
My AR Torque Thrust II (17X8) running 245/40/17's use 4 3/4" backspacing. The fender lips are slightly rolled. There is about 3/4" clearance on the inside front wheelhouse.
 
#8 ·
DaveSanborn said:
Will the interior side panels need to be altered (I have a Shelby GT350 seat delete)
Yes, and it won't be pretty.

Dave
I'm wondering if a talented interior guy could modify the existing interior panels by extending them in to sort of look stock.

Does anyone know how much the side panels would have to be moved in towards the center of the car?

Thanks-
Craig Backer
 
#9 ·
Does anyone know how much the side panels would have to be moved in towards the center of the car?
That's directly related to how much you want to move the inner wheelwells inboard. The interior side panels butt up against the inside edge of the inner wheelwell at the bottom of the panel... sans approx. .5 -.75".

You're presently running a rear seat delete. If you move the inner wheelwells in more than the aforementioned .5 -.75", you'll never be able to re-install the original back seat without also narrowing the seat... and this is a royal PITA.

A couple weeks ago, I mocked up a set of 275/45/17's on the rear of the '66 FB I'm working on. The wheel was a 17x9.5 w/5.5"BS. To get them to fit, I'll need more BS. I had at least an inch of clearance between the outside of the tire and the inside of the fender lip, so I'm guessing (at this point) that a 6" BS would fit the 275's perfectly.

My wheelwells have been slightly enlarged, the rear-end has been narrowed and uni-body structural pieces have been replaced in favor of a full frame chassis, so don't compare mine as if it were stock.

Your dilemma is one that most novices overlook...

... the "overbuilt" engine is worthless in a car that can't transfer that power to the ground. You obviously took the time and spent the money to build the
652bhp/620tq-6000rmp
engine. Now you'll have to spend a lot more to make that power useful.

I assume that you've tried all of the easier (cheaper) fixes? Traction devices, tire style, etc.?? When you have to stuff 315's, you'll need flares AND widened inner wheelwells.

Dave
 
#10 ·
Stock distance from frame rail to sheet metal is 11 inch +/- small variance for cars.

Here is a 275 on an 8 inch rim on a 65:

less than 1/4 to the frame rail and hard contact on the inner wheel well, a mini tub would remove the contact with the wheel well but would not move the frame rail.



 
#11 ·
DaveSanborn said:
Does anyone know how much the side panels would have to be moved in towards the center of the car?

stock.

Your dilemma is one that most novices overlook...

... the "overbuilt" engine is worthless in a car that can't transfer that power to the ground. You obviously took the time and spent the money to build the
652bhp/620tq-6000rmp
engine. Now you'll have to spend a lot more to make that power useful.


Dave
I didn't overlook the need for tire with this kind of hp. I just figured I'd have fun and spin the tires for awhile until it was time for bodywork. It's now time for bodywork.

The wheelhouse mods will be a drop in the bucket compared to cost of the build of the rest of the car.

-Craig Backer
 
#13 ·
The way I'm seeing things, I can get 6.5" of backspacing with a 1/2"- 3/4" of clearance by moving the inner wheelhouse in close to the frame rail. With a flat rolled lip, I'm guessing I can fit a 10" wide wheel.

Now I'm wondering about pushing the quarter out without flaring it to get another inch. Has anyone done this via moving the outer wheelhouse out to slightly bulge the quarter?

Thanks-
Craig Backer
 
#15 ·
There is a '65 FB that was in the Dec '04 Mustang &Fords magazine that was minitubbed and running 335's on 18X11's. The article says that shop that did the work was Hotwheels Custom autobody in Mount Vernon Washington...Hope that helps.

http://images.mustangandfords.com/eventcoverage/0705_mufp_35_z+ford_hot_rods+mustang_rear.jpg

http://images.mustangandfords.com/eventcoverage/0705_mufp_34_z+ford_hot_rods+65_mustang.jpg
 
#16 ·
Has anyone done this via moving the outer wheelhouse out to slightly bulge the quarter?
I'm sure someone has, but not me...

Take one of your rear wheels off, lay on the ground and look up. It's not just the apex of the outer wheelwell that needs to move outward, it's the whole circumference of the wheelwell. In the front, the lower portion of the quarter would probably have to be seperated from the rocker... to do it right, you'd need to "bulge" the whole opening. It's definitely do-able. Just bring the car to a good body shop with a 335 tire mounted on a 10" wide wheel and say "make it happen with no bondo and I'll pay cash". How it will "look" when finished is another thing.

Have you looked into the Eleanor style rear flares? This may give you the room you need, but it'll be close.

You've got an impressive drivetrain. Where there's a will, there's always a way. Like you said, the drivetrain was the easy part.

What kind of locker are you using?

Dave
 
#19 ·
DaveSanborn said:
tsk tsk... an 8" wheel with a 275 tire? :eek:

Dave
Yeah yeah...I needed the extra sidewall suck in from the smaller rim to fit the tire on the car anyway. I only use it for straight lines 12 seconds at a time ;) Those are drag radials and I usually only run 16-20 lbs in them
 
#20 ·
Do you have the web link to this Mag or any pics of the back seat area . ;)



fast68back said:
There is a '65 FB that was in the Dec '04 Mustang &Fords magazine that was minitubbed and running 335's on 18X11's. The article says that shop that did the work was Hotwheels Custom autobody in Mount Vernon Washington...Hope that helps.

http://images.mustangandfords.com/eventcoverage/0705_mufp_35_z+ford_hot_rods+mustang_rear.jpg

http://images.mustangandfords.com/eventcoverage/0705_mufp_34_z+ford_hot_rods+65_mustang.jpg
 
#21 ·
I'll check when i get home (after tricker treating with the kiddo) I have the magazine article and I did a google search for the owners name to find the pictures. I know they came from the Mustang&fords webstie. You can right click on the picture and get the properties.
 
#22 ·
fast68back said:
There is a '65 FB that was in the Dec '04 Mustang &Fords magazine that was minitubbed and running 335's on 18X11's. The article says that shop that did the work was Hotwheels Custom autobody in Mount Vernon Washington...Hope that helps.
I would make an arguement that it takes more than a 'mini tub' to put those tires on that car. My understanding of a minitib is it leaves the frame rail in place and simply opens up the wheel housing. A 335 doesn't fit between the steel of the fender and the frame rail so that would mean that they moved the frame rail...which to me means it isn't mini tubbed...it is tubbed. Just not tubbed enough for 15 inch wide slicks ;)
 
#23 ·
I ran home at lunch. The guys name is Jason Johnson. I did a google search for Jason Johnson 65 fastback and this was the site I got that had the pictues. The mag did not have any rear interior shots, just front seat and one of the trunk, but you can not see anything, there is a HUGE amp back there that goes from wheel well to wheell well.

Link
 
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