It's been a couple days since I've been logged in here so I just now saw this. We have and recommend a 315 tire on the 1st gen Camaro. I'm sure you could squeeze a 335 in there with a rolled lip and more of the frame rail removed. We used a Classic Industries stock replacement tub moved over to a slightly notched frame rail. We didn't notch the frame rail as far as needed for the DSE tub. With a DSE tub and some modification to our coilover crossmember you will have some more room than we do on our car.
Here are some pics I just took with my camera phone with the car on the lift. *camera phone so sorry for the low quality* The only time this tire rubs on the inside is on steep driveway transitions.
There is about .5" clearance on the outside
This one came out really dark but this is the inside clearance which is about .75".
This is the clearance of the bars and brackets.
This one shows our coilover crossmember and how much the rail was notched.
