I have both blocks a 440 and an early 400. Also a K1 4.15 440 crankshaft. I keep going back and forth over the advantages/disadvantages of either build to go into my 1968 Dodge Charger. Original engine was a 383 which is gone, automatic, 3.23 gear. It figured it could use the added displacement. Opinions? Thanks as always.

If you want to do an R/T clone do the RB, if you want to keep it OEM looking and prefer a 383 'sleeper' go with the B.

The RB is a little easier to build but the B fit's in the bay with more clearence all around and is (generally) a little bit lighter in terms of overall and bobweight. I've built several of both and both are awesome.

My current motor uses your same 4.15" stroke but crank offset ground to 4.30" and in a 4.375" B block for 517 cubes; it was a bit more expense than doing a 496 but I wanted to use the BB Chevy 2.200 journal 6.535" rods and since I wanted a custom design piston anyway it was not that much more to do.

Either way you can't go wrong but it also depends on what kind of HP/Tq target you're looking for and what gear/vert and type of use you have in mind. As my own personal 'rule of thumb' for a stock based block, I usually opt for the early casting Low deck 400B if the HP peak is going to be in excess of 625 or so or and/or the torque peak will occur above ~4500RPM. It's not a hard and fast rule, just a general 'apples to apples' and it really depends most on the application. Also, generally anything you can do to an RB comes out a little lighter and a hair more responsive on a B, due almost entirely to it's lighter bobweight, cube for cube.

I was just mentioning Russ Dudeck (BSB67)'s 508RB in his full weight 67 Charger on a related thread, might want to check out his site for some inspiration.

I prefer the RB for the ease of using longer rods and the generally better intake manifolds. The B Block is stronger when you go above 600HP though.

Sheldon

I would do, and have twice, what Streetwise suggests, have the crank offset ground on the rod throws to BB Chevy rod size with either 4.250 stroke or 4.300 stroke and have the mains turned down to 383-400 main sizes, also have the counterweights cut down to 7.25 diameter for balancing.My 505 bracket motor has a Ohio Crankshaft CO. 4.25 stroke in a 1971 400 block with Chinese, RPM brand, 6.700 long H beam BB Chevy size rods and Diamond pistons, the other block is in my street Duster with a six bolt flange Chinese crank that was offset ground to 4.300, it has 6.800 long CAT brand BB chevy rods in it with Ross dished pistons for pump gas Both motors are solid roller cam motors with roller rockers, aluminum heads and both make a lot of power. The 440 blocks have a history of breaking the main webs, I have seen or torn two bocks down with broken main webs Not so on any 400 blocks I have seen or heard of on here or anywhere else I did have ductile iron main caps put on both of my stroker 400 and one stroker 440 block, no problems on them so far If you don't want to make over 600 HP you can use either block, over that go with the 400 block 600 HP with a large(500C.I.+) stroker is not hard to do