Dirt Muscle Car

[Greg]

OK. I'm on board with this 37" idea.

You can get all the way down to 7.17 in D60 or D70 flavors.

I knew you'd like the big tires!

I've seen that... 4L80E with 6.17's? At least I'd have OD and it's really not going to see much time on the freeway.

 

[RockChucker]

Cantilever long travel suspension probably needs to happen now too.

 

[Greg]

Cantilever long travel suspension probably needs to happen now too.

We will see, I really want it to be built to class spec for the NORRA 1000. I know they have limitations on things like air bumps and coilovers, but I'm not sure how far outside of factory suspension design I'd be allowed to build.

37's are allowed... 😁

 

[Greg]

Figured I'd post some pics as I got the car, the cleaning process and the start of some mods.

Pics of the car-

The trunk on this thing is MASSIVE!!

The interior was a disaster, rat sh*t in piles, trash and mismatched interior parts. The front bench seat was plaid green & blue, but the rest of the interior was gold. Obviously not the original, plus it all smelled terrible. I tore out the seats F & R, started stripping out the carpet and the tar paper insulation underneath. The headliner was all but gone, with some bits still hanging down. It all got removed, then I sprayed it down with Simple Green. I spent about an hour pressure washing the car inside and out. Once it was dry, I splashed Bleach around on the floor to disinfect it and hopefully help get rid of the stink.

Since it was somewhat clean and the seats were gone, I had to toss one of the PRP seats from the TJ in the Bonneville and see how it looked. I'll probably run something like Corbeau's down the road.

After it was somewhat clean, I spent some time crawling under the car and checking out the floors, frame, etc. It's actually quite solid! The front tires are still bias ply, so this thing was taken off the road a LONG time ago!

 

[Greg]

After some time with a tape measure, I realized that the wheelwells are pretty decent sized from the factory. I pulled a front tire off and decided to roll one of the 37" KR2's into the wheelwell and rough check fitment. The leading corner of the fender was swept back towards the tire and in the way of fitting the massive tire. Knowing that I wanted to get a decent approach angle when it was built, I decided to cut on a body line, close to flush with the bottom of the front bumper.

Obviously more trimming will be needed, but it's a start!

 

[Greg]

I think I'm going to tackle this in stages, rather then the 37's right off the bat. I'd really like to get it running and driving with the 'stock' suspension and possibly some coil spring spacers for a little height. I'm thinking about running some wheel adapters/spacers from 5 x 4.75 to 5 x 5 and run some Jeep Wrangler takeoff wheels with 32" tires.

I'll use the Gen 4 aluminum block 5.3 that I have in the shop, hopefully a 4L80E transmission. Run them with a Holley Terminator X wiring/ECU setup. Probably add discs up front for safety.

Then after its been on the road/in the dirt for awhile, I'll work on tearing down the suspension, upgrading to 8 lug parts, the rear Dana 60/70, fitting the 37" tires, etc.

 

[I Lean]

Love. 😍🥰

 

[Unimog]

This is going to be fun to watch!

 

[Thursty]

I can’t wait to see this thing come together! 😎

 

[RustEoldtrux]

If you can find a set of original Bonneville 8 lug wheels, that would be awesome for your build. Probably no adapters available to fit on standard 8 lug hubs though.

 

[Greg]

Did you know that some older GM cars used a 5x5 bolt pattern, which is the same as the modern day Jeep bolt pattern?

My adventure trailer has 17x8 Soft 8 wheels with the Jeep 5x5 bolt pattern and 35" BFG KO2's. I was surprised when the Jeep bolt pattern fit perfectly on the '67 Pontiac! Unfortunately I only have 3 wheels are tires!

After testing my turning radius, it doesn't look like the 37's will work at all. The frame gets right in the way. As it sits with the 35's and these wheels, I'm getting into the frame hard with the wheel turned about 1/2 way. Not really a surprise, as I'm sure Pontiac never imagined 35'" tires on their cars. I'm not sure if a 1.5-2" wheel spacer would make much difference, but I may try them out.

 

[I Lean]

It looks like there's a fair amount of room to clear that tire with minimal work. More or less just build a box of sorts on the back side of the frame, then cut away where the tire is touching so the current back wall of the frame becomes the new FRONT wall of the frame, with your box making up the difference.

 

[Greg]

It looks like there's a fair amount of room to clear that tire with minimal work. More or less just build a box of sorts on the back side of the frame, then cut away where the tire is touching so the current back wall of the frame becomes the new FRONT wall of the frame, with your box making up the difference.

I was thinking the same thing, it wouldn't be too difficult.

 

[mbryson]

Did you know that some older GM cars used a 5x5 bolt pattern, which is the same as the modern day Jeep bolt pattern?

My adventure trailer has 17x8 Soft 8 wheels with the Jeep 5x5 bolt pattern and 35" BFG KO2's. I was surprised when the Jeep bolt pattern fit perfectly on the '67 Pontiac! Unfortunately I only have 3 wheels are tires!

After testing my turning radius, it doesn't look like the 37's will work at all. The frame gets right in the way. As it sits with the 35's and these wheels, I'm getting into the frame hard with the wheel turned about 1/2 way. Not really a surprise, as I'm sure Pontiac never imagined 35'" tires on their cars. I'm not sure if a 1.5-2" wheel spacer would make much difference, but I may try them out.

“All” the intermediates (A, F, X bodies — there’s always exceptions) have the 5 on 4.75 and “B” (for big) are the 5 on 5 pattern (I didn’t know they were 5 on 5 but definitely different than the smaller cars)

 

[Greg]

Alright, one more update with pics....

I pulled all 3 tires off the Adventure Trailer to bolt them up to the Pontiac. I pulled the front inner wheel wells out yesterday, to make room for bigger tires. With the little trimming on the front (both sides now done), both tires tuck right under the fender and clear sheetmetal.... for now, with the missing engine & transmission.

The rear was a bit more tricky, I put the rear of the frame on jack stands and dropped the weight off the rear axle... the rear shocks were limiting the axle droop, so I unbolted the shock and the axle dropped another 6"! After trying to fit the 35" tire out back, it was obvious I needed to cut more sheetmetal. The wheelwells were pretty rusty, so I didn't feel too bad about chopping it up. I traced out a line similar to the stock wheel arch, I needed more room up front than out back, so I cut 4" from the front, 3" from the top and 2" from the rear. I was able to leave most of the inner wheel well intact!

After that, I bolted up the rear tire and set it about the same as the front. As it sits, I'm thinking I'll need 2-3" lift to match the ride height as pictured.

I love this stupid car and idea!

 

[1969honda]

That is going to be sweet! Please make this happen and keep the updates rolling in every couple months with the TJ going on....

 

[Kiel]

Big tires or nothing....gonna be sweet

 

[Kiel]

I'm thinking that 37s look small actually............39's or 40s...... I'm sure you'll make it look great

 

[Greg]

That is going to be sweet! Please make this happen and keep the updates rolling in every couple months with the TJ going on....

We will see what happens this Winter, if the Bonneville gets some more work or not. But I am loving this thing, I'll see it thru. It's going to be so fun to drive!

 

[Greg]

Big tires or nothing....gonna be sweet

I'm thinking that 37s look small actually............39's or 40s...... I'm sure you'll make it look great

While I agree with you, the 35's are good for now. They're bigger than I initially planned and they just look right with the height and wheelbase. The 37" KR2 race tires would be epic, but fitting them isn't going to be easy at all.