The 500 is the largest **V8** ever used in a regular production car. Lets not get into double digit cylinders and industrial or crate engines. The 500 was the largest V8 ever put into a passenger car that roled down an assembly line.

As for direct swaps with the HT4100 look to Oldsmobile. The Olds 350 and 403 are pretty direct swaps. An Olds 455 can be made to fit, but it has a higher deck height than the 350 and 403 so you'll need to do some modifications. You just need the motor mounts, brackets, etc. from a Diesel Caddy (The GM Diesel of the early 80s was based on the Olds 350).

this might be a little off topic but wouldn't a high compression 472 get better fuel mileage than a low comp 425? Just wondering because I recently replaced the 425 in my 77SDV for a 1969 472 with 950 heads and a 6500 block.

Wow this thread grew a TON in the last 30 hours since I was last on here!

Anyways, will a '77-'79 Sedan deVille run a quicker 1/4 mile than a '75-'76 deVille? I think so. I think it's like 17.5 or so for the 425 and like 18.1 for the 500.

yes.

Having had a 78 Fleetwood Brougham and 75 Deville, both stock, they're both equally slow. I'd dropped the beads out of the cat on the 78 and after that it was noticibly faster.

The '76 will win. It has a much better gear ratio for 1/4 mile times.