Reply to "Net and Gross HP"

Horsepower ratings for the US made 351C 4V

1970: 300 SAE Gross BHP

1971: 285 SAE Gross BHP

1972: 280 SAE Net BHP

1973: 264 SAE Net BHP

1974: 264 SAE Net BHP

The change from gross to net horsepower occurred in 1972. These figures are from memory, so go easy on me if I've made an error. AK Miller, a Ford contractor, tested a production line 1970 351C 4V and found its max bhp was 287 not 300. Ford was being optimistic. the test results were published in Hot Rod Magazine. It is often said by enthusiasts that muscle car horsepower ratings were under-rated to avoid insurance penalties, but in the case of the 351C this is not true.

Having driven 1970 through 1973 Mustangs with every V8 power train option, my impression is that the 1972 cobra Jet was the most powerful of the 351C 4V motors (hydraulically cammed versions). It was stronger than the 1970 & 1971 versions, which were choking for air by 5500 rpm due to the small 600 cfm Autolite carburetor, small cam & single point ignition.

A common trick in the seventies was to stick the 1970 heads on the 1972 cobra jet, and install the OHO hydraulic cam (same timing specs as the Boss 351 cam, 0.505" lift). Equipped in this manner the motor was very strong over a very wide power band, it was a Boss 351 that didn't need its valves adjusted. Adding headers and a 750 Holley pushed its output to 370 to 380 bhp. The motor idled with a slight lope and had good drivability, and exploded into its powerband at 3000 rpm. The sbc & Mopar guys had nothing equivalent, yet the Cleveland could do this with just a few bolt-ons.

cowboy from hell