you could certainly add some gussets but the frame is probably stronger than the original mild steel side rails that come on the car, a couple of gussets would not be a problem though
(Im a 55 year old 6'2" 280lb fat ex rugby player so probably have you beat on the weight side)
I'll send you a picture of my 76 Cadillac with the 8.2L 500ci engine for the rugrat. I am just about to add an 8-54 blower with wet nitrous injection and it has been known to suck ricers up its air intakes. Of course when I run it I'm lucky to get 5 or 6 mpg although I have had her up to 11 when cruising on the freeway
