'70 455 SF Engine Questions

[Guest]

I bought a 455 supposedly out of a '70 LeSabre Custom. The ID code stamped on the deck is "SF". According to the Standard Catalog of Am. Cars the engine is a 370 HP optional engine. Heads are small valve (2.00 dia intake, 1.625 exhaust), casting no. 1231786. Cam has a brown stripe between front journal and first lobe.<P>What is different about this engine compared to a 350 hp 455 to give it the extra 20 hp rating?<P>Thanks for any help you can provide.

[Guest grisby]

Same engine, same block, except for insurance purposes they (GM) rated the A body GS 455 as 350 horses. It was a numbers game back then. Large Buicks were the B,C, E bodied cars and GM had horsepower to weight limitations for the smaller(in yesterdays terms) A body vehicles. The SS block which is a stage 1 is the same block etc, EXCEPT it had a hotter cam, different distributor, different carb and a larger bowl fuel pump and of course the bigger valves. So in essence the Stage 1 which was rated at "supposedly" 360 horses was a heck of a lot more than the 370 standard head SF block which was in the B,C and E bodied buick cars. Remember in those days the hp was measured at the flywheel in 1970, without all the "accessories" and not at the rear wheel.<BR>bill g<P>[ 08-03-2001: Message edited by: grisby ]<p>[ 08-03-2001: Message edited by: grisby ]