I remember seeing that ad and others from H-M. My old pal Randy Migut bought one of their Cammers, the dual four barrel version for about $2,000, long ago now.
But I had to laugh then and now too about the aluminum 351C blocks. Precious few were ever made and the few that were went to folks like Dyno Don Nicholson. Not NHRA Pro Stock legal in the era, he ran them in match races only. That great old mag, Super Stock & Drag Illustrated had an article on his match race setup with those hi-ported alum. heads and matching alum. block. Later, fellow Illinois resident and racer Animal Jim Feurer bought out his entire stash of Pro Stock small-block engines as the big guns switched to Boss 429 engines.