Frame on 90' 5.0 mustang....HELP

my frame on my 1990 mustang gt (5.0 with the manual) it basically broken out right ahead of my rear right tire...my front right tire tends to lift off the ground on full acceleration to that might be part of the problem buts still drivable as long as i accelerate slow because when i give it gas the car pulls to the right, when i let of or shift it pulls back to the left... this started happened 2 days ago right after i got my new
"King Cobra" clutch assembly from summit racing products....the framewas busted out there befor the clutch to its just that it didnt have handling problems like it does now

the only thing i can think of to fix it is to weld plate steel on to the busted part. or i was thinking of making my own subframe connectors which i think is the best... it would help my handling but not fix the problem.....any help would be greatful...

the drags start tonight at W.I.R. and i got a broken frame...so i need help quick...

best thing would be to fishplate the frame AND put in some frame ties. Unibody cars twist way too easy. A 6 or 8 point cage would really do a lot towards getting the flex out of the car.

I have an 84 and 85 mustang, 2 84 capri's just sold 82 mustang All 5.0 HO 1 4 speed, others 5 speed.. the chassis is not heavy enough for more than grandma style driving. the police 5.0 had additional bracing added at the factory mod area..
it.s been a while since i looked under anything newer than my stuff..
I bought the tubular frame reinf kit, used 1/4 14 drill point screws to hold it in place then screwed 1 x 2 steel tubing under the rockers tight to the down flange. I then measured and cut cross pieces and used a hole saw in the drill pres to make the cross bars fir to the round tube.. tacked them together then dropped it out to finish the ladder welding. I also ran a longer piece under both front seats. I had the inside gutted then reinstalled and started welding and screwing it in also made up more gussets and fish plates
when I was under I noticed cracks under the rear seat so I bent a piece of 1 1/2 x 1/8 angle iron to match the floor contour and welded it in.
One of the ladder section cross pieces is under the rear passenger foot wells and that is where I bolted in the roll bar so it has more than sheetmetal incase I ever get upside down.
I have a gw cowl-shock tower kit but haven't put it in yet. one of the Ford design engineers said they really don't help that much but since the 65-66 shelby must has them everyone wants them if they start hipo mods.
I added welds to most of the panels in the engine compartment. we used to do that to 65-66 shelby mustangs in the factory.. I also added a tubular reinf at the radiator support. I think the first factory proto 5.0 bent the original design when they put wide aftermarket tires on and ran some hard corner tests.
with the frame stiffened up and wide tires it over works the original style clutch. I have the parts but have been too busy to change It to the larger flywheel., chutch etc.

Did the actual frame brake or did you just rip out your torque box (where your upper control mounts)? If that is the case. You can order a kit from summit to "box" it. It is much easier to do before they break but nevertheless. I suggest taking out the back seat and welding them in from the top as well as the bottom.

Also while you are at it a set of subframe connectors would be nice.

this is a problem with them all, they go there or just under the front seat mount. Get the frame ties and plate the rear like Severson sugested. If your not a welder have someone do it for you, because it sounds like you like to launch this thing. Be safe