Alot of great Yank iron getting discussed here and it's easy to see why, I'd give my eye-teeth for some of it.
My favourite engine isn't quite as famous
The 2.0 16v C20 X E (redtop)
Most of the volume car manufacturers were hotting their hatches up with breathed-on 8v units. The head of GM Europe summoned his engineering senior staff and told them to come up with something that would blow the competition away. They did.
They created a 16v head and replaced the bottom end crank train with Mahler parts. Engine management was the aggressive Bosch Motronic 2.8. It was a track engine disguised as a road engine, but only just. Peak torque was 145lbf@4600rpm and the horses were 150bhp@6000rpm. The fun was there but you had to be driving pretty damn fast to be getting the best out of it. Bore and stroke were 86mm and compression ratio 10.5:1, which stopped short of all-out race engine.
The 8v hot hatches were totally blown away by this comparative monster.
It was and still is very tuneable, alot of companies still producing aftermarket enhancements for an engine that ceased production in 1994. Will still make a more modern performer work hard for it.
Not a refined engine, a healthy unit will sound quite raspy to the uninitiated. New EEC directives on emissions eventually sealed its demise. A great engine, for me; still has a big fanbase of followers.
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Mine's on the bench down to nuts'n'bolts, all the reusable bits mostly chemically cleaned up by now, rebuild should start in the next few weeks. Looking at fast road cams and a lighter flywheel as add-ons. Remap once it's road-going.
Edit: Almost forgot, only had one motorcycle and that was a Harley-Davidson 1340cc FXSTC. Fantastic fun for plodding around on. Didn't handle, you had to get off and push it round corners in the rain.
That would be my fave motorcycle engine, loved the agricultural long-stroke beat of the motor but the vibration through the frame at speeds over 80mph would probably render you sterile. If you stopped for a coffee after a high-speed run, it was impossible to talk to anyone unless they were vibrating at the same frequency as you.