My first sleeper was a 1986 Ford Crown Vic. retired Oil field car. Always get retired police/ taxi package, heavier duty suspension and electrical system. held up rather well. Managed to shoehorn in a built 460/ c6. Looked like grandmas grocery car. Ran solid 13's. wish I never sold it.
Back in the mid 90's I put a 350 in a 79 Mazda GLC, the little unibody car was plenty strong enough to handle the torque of the V-8. The rear end couldn't handle it though. It ended up with a S-10 rear end which was only a 1/4 inch wider than the stock. Just point it and pull the trigger. That thing only weighed 2300 lbs with the V-8.