lesser known muscle cars

I can think of many. The 72 Torino wouldn't be one of them though It came standard with a 302 (140 hp) and an optional 351C (248 hp) and 429 (205 hp). Not exactly quick in a 3600-lb car

The 401 AMC in '74 was advertised at 235 hp, but it actually only made about 185-200 depending on which cam was used. They switched cam manufacturers mid-year from Erson to Ackerson and power dropped a little.

How about a 1970 Eldorado? 500 ci / 400 hp engine that made well over 500 ft-lbs of torque.

1970 Stage 2 buick GSx The stage 1 was rated at 510 ft-lbs and the stage 2's numbers weren't even advertised. It was a 12:1, forged piston, solid lifter monster.

Great examples, yeah when it comes to the smog era cars most need mods to wake up their engines, although they were quick at the time.
The 1972 GTO with 330 bhp LS5 455 HO motor was a good looking car, I think honeycomb rims were std that year. That car was designed to run on unleaded and was still quick.

401-XR Gremlin

72' GTO 455 HO

True. Its also confusing since HP ratings went from net to SAE in about 71. What was once a 330 hp car became a 280 hp car even though it had the same power.

Yeah, for the 1972 LS5 455 HO engine they somtimes listed 330, and then 300 bhp, for gross and net, pretty confusing. Power levels did drop from 1970 to 72, but not as dramatically as the figures suggested because of the SAE change.
Also, to overcome the power losses after the universal CR drop the manufacturers sometimes brought out bigger sizes to compensate, like the 455 and 401 (Vs the old 428 & AM 390 respectively). These lower CR engines made less power, but more torque at lower revs.
One car that gets left out, and is probably the best looking Mustang II of all time, was the Monroe Handler.

1975 Mach I 302

Monroe Handler

how about the 68 plymouth fury? i think it would make for a nice muscle car....

The 1970 Ford Torino King Cobra is a model that not many know about. Built to take on the winged Daytona Charger before NASCAR rule changes unfortunately sidelined these great machines.

Torino King Cobra pic 1

Torino King Cobra pic 2