Re: 390 vs. 351/400
how r ya mate. 390 is a top engine, strong as hell, and as heavy as too. comparing all motors in as stock condition the 390 and 351 are fairly close on hp but 390 wins slightly on tq. power and tq are at lower revs in the 390 than 351. in an f100 the 390 will slightly out do a 351(talking clevo here) but the 351 will catch it as revs and speed rise. 400 clevo block is different to 351. 400 has larger bearings longer rods and aprox 1 inch taller deck(block) height. all 400's came with 2bl carb but had huge tq. , over 400ft/lb's. in an f100 a 2bl 400 will way out tq a 390 or 351. fit a 4bl intake to the 400 to up the hp and the 351 and 390 will not even come close. 400clevo's share the basic gasket set, heads, sump, cam and timing set, oil pump and a few other bits with the 351. there is a 351 that uses the same block as the 400, this is called the 351m ( m stands for modified, from normal 351c) it has same bearing sizes as 400 but same stroke as 351c. (351. 4"bore/3.5"stroke. 400. 4"bore/4"stroke) some refer to the 400 as the 400m, this is incorrect. it is a 400 cleveland. give me an email if ya want any more info. cheers.