A crate GM 572 dart block, ready to run long block on ebay 745 hp 700+ft lb of torque $10,000.00 and change. A hot rod engine a bit much?
You can find factory new crate 454 ci engines from a bit over $5,000.00. If you go the time to shop via phone, you can have one of the builders put a cam suitable for a Mh in the engine. They must be charging a lot for removal and installation, which can be a challenge I'm sure.
Just an option. If your insurance is handling it let them do their thing and they might even rent a car for you for a period of time.
Dealers are gettign really out of lien today on prices on everything. Son' 07 Soltice jsut had the A/c reworked and then it quit again. $400.00 for a half hours work and four sensors that would coat after market $20.00 each at the mos
If I was younger you give me a check for that amount, I'll give you a motorhome ready for super Stock, so to speak, not literally.
On edit, of course you put in a stouter engine more heat so bigger radiator and oil cooler and trans and cooler. And long tube approprate headers will help with cooling. The mufflers would be bigger of course.