so if i open the hood on a car and see a big block mopar engine sittin' in there, how do i tell if it's a 383, 413, 426 (wedge; not hemi), or 440? do i have to look at numbers or is there a visual difference?
you can tell the B motors (350, 383 and 400) from the RB motors (413, 426, 440) by the deck height. Look at the flat portion on the front of the block next to the distributor. if it is basically flush with the rest of the block, then it's a B motor, if that same area is raised, then it's an RB. Also the RB motors are noticibly wider than the B motors on account of the taller deck. Casting numbers are your sure shot though
look for the pad by the distributor. B motors will have the pad on the right(passenger) side of the distro, RB motors have in on the left(driver) side. RB motors are the following displacements: 383, 413, 426, 440 B motors are the following: 350, 361, 383, 400. 350 was only built in 58, a very rare motor, and 383 apears twice, as they build both versions of it. years of production: 350: 1958 361: 1958-1965 383RB: 59-60 383B: 1959-1972 400: 1971-1978 413: 1959-1965 (industrial 413 produced til 1972) 426: 1963-1965 (appeared in an industrial version as well for a few years) 440: 1966-1978 The pad will be stamped with either two or three numbers indicating the displacement. for example, if it says 440, XX44, XXX440, it's a 440, regardless of the prefix letters (the X's). it seems the guy stampling the numbers was lazy, as a lot of times the first two digits of the displacement got stamped. 41=413, 42=426, 38=383, you get the idea. David
You can also check out Year One's web site they have good info on block and head numbers. On a mopar block you can also find out where and what time your block was cast.
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