Here you go. As you can see the 72 cleveland was nothing special. So in my opinion you would be paying too much.
Bax
H-code
The majority of 351 Cleveland engines are H-code 2V (2-venturi carburetor) versions with low compression. They were produced from 1970 through 1974 and were used on a variety of Ford models, from ponycar to fullsize.
M-code
The M-code version was produced from 1970 through 1971. Both years offered quench heads but 1970 offered a slightly higher (advertised) 11.0:1 compression ratio whereas in 1971 the chamber was opened up slightly reducing the advertised compression to 10.7:1. The 1970 4V head is identified with the proper date code casting and a "4" cast on the upper corner of the head. The 1971 4V head is identified with a "4*" (four-dot) casting at the same location. Hydraulic lifters were also specified, with the M-code producing about 300 hp (224 kW). 2-bolt main caps were used along with a cheaper cast iron intake manifold.
1971 R-code (Boss 351)
The 1971 R-code "Boss 351" used higher compression (11.7:1) with the quench head 4V heads, solid lifters, an aluminum intake manifold, and 4-bolt main caps. so It produced about 330 hp (246 kW).
1972 R-code
The R-code 351 Cleveland for 1972 was considerably different. It had reduced compression for emissions compliance and used open-chamber heads. It had a solid lifter camshaft, however a four barrel carburetor was retained. It produced 275 hp (205 kW) using the new SAE net system.
Q-code (Cobra-Jet)
The Q-code "351 Cobra Jet" version was produced from May 1971 through the 1974 model year. It was a low-compression design that included open-chamber "4V" heads, a special intake manifold, special hi-lift long duration hydraulic camshaft, special valve springs and dampers, a 750 CFM 4300-D Motorcraft Carburetor, dual-point distributor, and 4-bolt main bearing caps. It was rated at 266 hp (198 kW) (SAE net) for 1972 when installed in the Mustang and 248 hp in the Ford Torino and Mercury Montego. The horsepower rating dropped in 1973 to 246 hp for the 4-barrel for the intermediate Fords, and still retained the higher 266 hp rating in the Mustang. The 351 CJ (now referred to simply as the "351 4V") was rated at 255 hp in 1974 and was only installed in the Ford Torino, Mercury Montego and the Mercury Cougar.