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.