welllllllll.......... here is my $.02 on the mustang idea.... and i just happen have my 64 1/2 coupe sittin up on the chassis table right now. initially i thought about doin the SN65 treatment(full sn95 "pan"), ... but finally decided against it for a few reasons. so im bck to square one.
now this is really a backburner project, as my 34 truck is priority after paying jobs.... so i have been mostly thinkin about different ways of doin it.
i have a few priorities with the project that seem to be the biggest problem, #1, the car will be a daily driver, weekend autocross/track car. #2, the car will be really low... most mustangs are usually about 1-2" lower than stock, mine should sit about 3-4" lower than stock.
the first problem i have with the early mustang platform........ is the complete lack of anything structural....... frame connectors are at best just a bandaid for the piss poor structural design. the fixed front rails are really nothin more than 16-18ga sheetmetal, and really rely on the shock towers and the rest to hold it all together....as its a true unibody. an aftermarket weld in crossmember that gets rid of the shock towers has got to be one of the "sketchiest" things that can be done to the early mustangs, granted for 99% of the people that just "cruise" their cars.... its more than enough, not for me.
well for my project i already decided it will use a 3 link on a sn 8.8 (track width will be more as i want minor flares) i really like the design of the top mount that you have pictured... so something similar will be worked out for this car. the rear is the easy part.... now working forward. a complete chassis stiffening kit, similar to what mustangs plus sells, ties the rockers to the t-boxes f&r, then ties back to the frame connectors. it also increases the size and effectivness of the the front torque boxes....and drasticaly increases the strength of the rockers... which in any unibody car are extremly inportant.
now that we have the chassis rigid from the firewall back we start with the front frame "stub"... and this is the point where i am at on the mental drawing board. ideally you would make something that ties into the factory rails...unfortunatly, they are way too thin to tie anything into... and without the towers...they are nothin more than sheetmetal spot welded to the floor pan.... so in reality.... the stub would need to be constructed with the sfc's as part of it. the front of the stub would triangulate back to the top of the beefed up t-box.
for front suspension i was planning on a sn based "k-member" converted to sla setup, and use a hub carrier type upright, so 13"sn cobra brakes could be used.
the main downfall to this whole set-up is gonna be added weight, and obviously install. i cant see the weight difference being more than 100-150 lbs, after the stock "everything" is gone and new "everything" fabbed up outa lil heavier material, i think its a small price to pay for a stable and rigid platform without a full cage. the install is what the real killer is, as there is nothing "bolt-on" about it, major welding and fitting issues will prohibit the average guy from stepping up to the whole system. where this isnt a big deal for me in my one off situation, it would be for 99% of potential customers.
this really sounds overkill...and probably is. but IMHO early mustangs are crap, they were the geo metros of the 60's never ment to become true muscle cars, so by expecting them to handle and perform with todays "standards" the entire system needs a complete rework.
i have driven quite a few early mustangs, one of which was a gt350 coupe(1 of 6).... i got to flog it around the kart track(our local autocross venue), and while the car was better set-up for road racing than my car, i found it to have the same "issues" with chassis flex and poor steering, inconsistant "feeling" etc....as EVERY early mustang i have ever driven with "stock" chassis config. so yeah.... overkill for one guy...means its just about right for someone like me
anyway...these are just my ideas.... i cant wait to hear what you have in store....... as you said...there really is no "support" for the early mustang crowd. (im leaving out 1 place.... as i dont like them, after talkin on the phone with them, gxxxxs motorsports can kiss my a$$)