1977 Camaro Z28 Resto Mod Build

There is no perfect single rear differential. Stock or aftermarket.
A Ford 9 inch can still fail even full race.
When used dirt tracking Left hand turns the Right hand axle tube fills up 100% with all Resevored sump gear oil.
The Ring and pinion run dry.
Oil coolers and lines will be ripped off from rocks , Mud , debris, parts falling of of other cars.
The solution is to install a special RH Axle tube oil seal & Fill the diff with 1-1/2 gallons of gear oil.
Too do so you must install weld in a Fill plug tube at the top of the Banjo housing.
10-Bolts GM still favored by many Pontiac guys. 10's & 9"s have been ran on them reworked.
Dana 60 is still Strongest. Best for drag race.
You have a street Pro Touring car build.
Moser 9 just fine.

So, I am tearing into the rear seat belt humps. Despite so many people talking about "bashing" in the area with a hammer, I could not find anyone posting what they did. I am not good at searching the forums here, so that could be the issue. However, I am documenting what I am doing. I am NOT just bashing it in, but cutting and welding.

So, as a refresher, here is the hump (passenger side) as-is. The silver sharpie line is how far forward the tire goes.


I cut out the seat belt mount to move it towards the front of the car, like would be done with the DSE mini tubs.


The fastener (bung?) is welded to 16 gauge steel with a 20 gauge panel spot welded to it.


Here is another view which shows the "bung" better.


I drilled holes from the inside of the car at the height of the platform there so I knew where to cut the bottom of the inner wheel house.


Next, I cut along that line and along the crease at the top of the hump. I then bent that piece in roughly along the contour I wanted for the new shape.


I then split the metal at the bottom and made some relief cuts behind so that I could move the metal to line up with the shape I wanted.


You can see the shape along the bottom now. It is pretty straight along most of the edge. We have gained about 1.5"


This is what the inside looks like after the cutting. You can see the new hole I cut to accept the seat belt mount sandwich (I removed the 20 gauge sheet from the top). I cut the 20 gauge back a little from the 16 gauge so I can weld the 16 first, then come back and put the 20 gauge patch over the whole thing.

87vette81big said:

There is no perfect single rear differential. Stock or aftermarket.
A Ford 9 inch can still fail even full race.
When used dirt tracking Left hand turns the Right hand axle tube fills up 100% with all Resevored sump gear oil.
The Ring and pinion run dry.
Oil coolers and lines will be ripped off from rocks , Mud , debris, parts falling of of other cars.
The solution is to install a special RH Axle tube oil seal & Fill the diff with 1-1/2 gallons of gear oil.
Too do so you must install weld in a Fill plug tube at the top of the Banjo housing.
10-Bolts GM still favored by many Pontiac guys. 10's & 9"s have been ran on them reworked.
Dana 60 is still Strongest. Best for drag race.
You have a street Pro Touring car build.
Moser 9 just fine.

Click to expand...

Yeah, I would have had to re-work the 10 bolt. It can be done for the power I plan on running. I did not want to do that. I like the look of this rear end much more than the GM rear ends. So, it was mainly an aesthetic choice vs. a 12 bolt. The price was about the same from Moser.

Got the seat belt mount moved to its new home.


After that, all the 16 gauge metal was welded up and ground down.


I then put a patch of 18 gauge over all of that and moved on to the wheel house patch.


And a look from the inside


This whole process gave the seat belt area just as much clearance as the rest of the inner wheel house. The radiused front edge of the patch is about an inch forward of my tires, which are 285/40R18. So, if you need a little clearance, this might be a good way to go without mashing up your seat belt hump or going full-in mini tubs.

Very nice work and great photos.......thanks!

That bring back memories

Nice job, can't tell you how many I beat in with a BFH in the 70's-80's on street/strip cars so we could run wider wheels with ET Streets without needing custom backspace.

Its not a modification I would do to my.own 70 T/A.
Never took a BFH To the Wheel wells.
I have known lots of Camaro guys that have.
Its a Pro Touring build and wide rubber desired.
Drag Racing only all you need these days is Mickey Thompson Drag Radials to Hook up and get into the 8's if you have the HP.
P275 60R15's.
Fit the stock wheel wells perfect and no banging anything .
5.0 guys run same size M/T drag radials.
6.99 at 202 mph with 2,000 Hp on tap has been done on them.

Comp Engineering Slide A Link Traction Bars I have also.
Amazing launch traction at Track and street with them.
Still corners OK.

87vette81big said:

Its not a modification I would do to my.own 70 T/A.
Never took a BFH To the Wheel wells.
I have known lots of Camaro guys that have.
Its a Pro Touring build and wide rubber desired.
Drag Racing only all you need these days is Mickey Thompson Drag Radials to Hook up and get into the 8's if you have the HP.
P275 60R15's.
Fit the stock wheel wells perfect and no banging anything .
5.0 guys run same size M/T drag radials.
6.99 at 202 mph with 2,000 Hp on tap has been done on them.

Comp Engineering Slide A Link Traction Bars I have also.
Amazing launch traction at Track and street with them.
Still corners OK.

Click to expand...

Sure, to each his own. I like the look of the wide tires, plus I want traction on the street where this car will spend most of its time. I remember how squirrely my 74 was back in the day. So, more traction = more better for me.

Brian, your 70 doesn't have the seat belt humps. They weren't needed till they started installing retractable rear seat belts . Think that was 73? The early 2nd gen bird rear wheel wells without the hump can take a 315 tire without even rolling the fender lip, I did it.

Erik, the 285's are a nice fit for your car with the hump removed.

NOT A TA said:

Brian, your 70 doesn't have the seat belt humps. They weren't needed till they started installing retractable rear seat belts . Think that was 73? The early 2nd gen bird rear wheel wells without the hump can take a 315 tire without even rolling the fender lip, I did it.

Erik, the 285's are a nice fit for your car with the hump removed.

Click to expand...

Thanks, more good info too. I like the 285's in there.

Ok, I have wrapped up the seat belt hump mods. I think it came out pretty nice.
All the welds were covered with short-strand fiberglass



And after a couple of coats of epoxy primer, things look pretty nice!

I also just got my rear end back from Moser after getting all the 4 link brackets welded on properly (I had tack welded them) and powder coated. If you want this color, it is called "Display Red" and it costs $200 extra. Looks pretty awesome though.


And after installing the center section

Yes I love that color, looks very awesome.

Indycars said:

Yes I love that color, looks very awesome.

Click to expand...

Thanks!

yes ,darn impressive looking differential

Grumpy said:

yes ,darn impressive looking differential

Click to expand...

Thank you!

Hey hey! We got the rear end done and installed in the car. It looks great under there.


Here is the ride height at the moment. We can raise/lower it about an inch using the brackets on the 4 link. The wheels look they clear just fine except maybe when the rear end is cocked near maximum with the passenger side high. A 1/8" spacer will fix that if it is a problem. No issues with the lip either (unrolled).


After we got done with that, we slapped some panels on!


Whaddya know! It looks like a car again!

Coming along nicely!!

Enjoy the pictures and progress!!

Curious if you're keeping the Cat Converter hump in the passengers floor ??

Thanks
Randy

GLHS60 said:

Coming along nicely!!

Enjoy the pictures and progress!!

Curious if you're keeping the Cat Converter hump in the passengers floor ??

Thanks
Randy

Click to expand...

Thanks Randy. I am planning on keeping that. I had not heard of removing it. Don't the crossmembers follow that same contour?