Under a classic Camaro, big rear meats are as American as apple pie and superchargers. It’s also more than just an aesthetic deal done to look cool. Larger tire width equates to more grip. With engines getting more and more potent, it’s challenging to get that power mated to the asphalt, especially when the road becomes curvy.
Detroit Speed and Engineering (DSE) is in the business of making old iron handle like modern sports cars. Long ago, they saw the need for wider back tires and came up with a straightforward solution: Mini-tubs. Think of them as factory inner wheelhouses on steroids. We’ve covered the install of these sheetmetal marvels before, but this time we wanted to see how they would drop into a convertible . After all, why should coupes have all the fun?
Here’s the key players in our little sheetmetal ballet. Designed to replicate the look of factory inner wheelhouses, these mini-tubs from Detroit Speed and Engineering (DSE) have one big difference: they’re deep. How deep? How about enough room to stuff in a set of 335 tires?
The limiting factor on fitting big meats under a first-gen is the shock mount placement. If you are going with an aftermarket rear suspension like DSE’s Quadra-Link, then you can just ditch these mounts. If you want to stay with leaf springs, then DSE has you covered with all the parts necessary to relocate the shock mounts inboard of the framerails. This ride is going four-link, so all we have to do is widen the tubs.
The first thing we came to grips with is that a convertible is not a coupe. Without the roof support, GM beefed up the support structure behind the rear seat, so there’s a lot more metal tied into the stock inner wheelhouses. There’s also the matter of the brackets for the convertible top which are also attached to the inner wheelhouses.
Even with these extra structures, the process for installing the mini-tubs is pretty close to how DSE instructs for the coupe. First, a line is scribed about 2 1/2-inches from the stock wheeltub. Remember, it’s better to cut too small than too big.
Once this project is done, the seat back will be a few inches shorter due to the wider wheeltubs. Rather than take this out of the ends where we have nice flanges to work with, we decided to take it from the inside sections. This should give us a more factory look when we’re finished.
With the cut made, we drilled out the spot-welds from the front and rear of the section we wanted to remove. We then cut it free from the stock wheeltub and removed it from the car. Once out, we cleaned up the flanges and put the seat braces aside until later.
Here’s the biggest challenge compared to doing this surgery on a coupe. The bracket for the top mechanism can’t be allowed to move up, down, or out. If it’s off, then the top won’t function properly. We tack welded a couple of braces in place to keep it positioned while we removed the stock wheeltub below it.