Frame Question

OK, my '65 Lark Convertible drag car is going on a diet, and I was wonder how much, and where would it be safe, to cut some of the "boxing" out of the frame. A convertible has a boxed frame, which has to be heavier than one from a hardtop. So "swiss cheesing", or cutting "lighting holes" shooting to be more like a Hdtp. than a convert. The car has a full roll cage, NHRA Certed. to the mid 8s, so it is ridgid, just don't want to hurt the structural integridity, not that pushing a 3600lb car to low 9's at 145+ doesn't already.......If you happen to have pics. of your handy work, I'd like to see them.
Gary G.

 

Gary
I know cutting the x-member out below the oilpan and replacing it w/ tubing saved some weight but on the framerails where you're talking we actually added plate to make the fourth side.

3600 I assume is w/ driver?
Curious to know what your new crank will weigh for one........
What trans x-member do you have?
How about engine mounts?
Brakes?
What all is f/glass?

 

I myself would leave it alone.The car will loose some strength being it's a convertable you need all you can get. Plus a stiffer car is easier to tune.

 

Thanks Kevin & Gary. Gary yes, 3600 lbs. with driver, actually alittle more. I have fiberglass bumpers, and very light weight aluminum bumper brackets, all window regulators are gone, and Lexan windows, windshield is still glass, tranny X member is the stock flat stamped steel one but I did swiss cheese that, front & rear brakes are Wilwood Discs, I know that I can get about 40 lbs. more out, I'm taking out the convert. top pump and actuators and will replace the actuators with aluminum bar. I'm not going to spend thousands for Fiberglass doors, hood, or trunk lid, doors are gutted, hood has been lightened, car has the bare minimum. Like I said you get to a point where you'll end up spending a ton of money just to save a few pounds, I just don't think the cost is worth the weight savings. Plus like Kevin says, "I'm Broke..!"
I still plan on lying under the car looking the frame over for some weight loss areas. The new crank, I'll weight it when I see it, which will be very soon. Motor mounts are hand made solids similar to stock. I will also be doing some cutting on the X member, the deep pan makes it pretty hard to get the motor out. One thing to mention, I still have the 250 and 300 Nitrous Jets that I haven't tried, that's just like losing 100 lbs. or more!
Gary G.

 

When I was going to race my '70 GS 455 convertible, the plan was to swap in a regular coupe frame. Then adding the cage would stiffen everything back up without gaining extra weight. I know you're too far along to go swapping frames, especially with the cage already on board. The weight difference between the two stock frames was 50# for whatever it is worth.

 

gary for what itis worth i was talking to a guy who is really in to 65 larks and weight etc he told me//and showed me that a conv has a extra stiffener inside the rocker pannels itis about six foot long 4in high ///dont know the weight but if your serious looking to lose the weight there 20 ib or so ( he found this when he replaced a quarter and figured ti is only on convs and is a stiffener) luck pete