take what you have there. and improve it to your satisfaction, but retain the spirit of the original build. A 283 is period as is the chevy rear, a well used and established upgrade of the time which most likely puts your car in the 60s build era.. Right in the American Grafitti period Go watch the movie and get in the zone.. Then have the new shop take the car to bits, clean up the original frame. Since the original X members are missing whats the problem adding either full or partial boxing and in keeping with the early build style use simple box section to fabricate replacement gearbox X member and a rear running K to stiffen things up just a wee bit .. and replace the rear X with something similar, or better still retro fit an early ford rear spring X member and have it tweeked to retain the stance.. A 40 rear X member would fit the bill. Just a lot tidier and properly welded Running gear. Well dude, its all there, why waste money and also loose the feel of the car your pops loved enough to make ithis.. Keep the chevy rear, its pure nostalgia, just detail it .. and fit new brakes which will just be service items costing pennies. You got a decent box in it, detail it,. The motor runs, so dont go nuts, give it a full service, fit new contacts,plugs and filters ( maybee the early 283 doesnt have filters ? ) and fresh oil, all cheap and easy and it will let you know if the motor needs a rebuild before you go tearing it to bits to find out .. Fit a new master cylinder and as a wee upgrade and a knod to saftey fit a dual circuit one .. New king pins, bearings and brake parts on the front, and check the steering box for excess play, adjust it lube it and drive it . Detail the motor with period bits if it runs good and be done.. Remember, its a toy, its not a true daily and neither will it be if you choose to sink 50k into it .. it will sit in the garage just the same .. How fast can you go on the blacktop 30 40 50 60 and 70.. with your juvenile cap on you can do 70 in a 40, if you can handle the fines and suspensions so why the need for 200bhp ? seriously they can be fast enough with a banger motor in them lol.. Its a shame the last shop blasted it .. but hey its done now . Best thing you done was rescue it from there grasp.. Has great potential and for a minimal outlay you can have a safe period hot rod without ripping the heart and history out of it ..