1972 charger engine build-up

[turbo72charger]

hello i have a 1972 charger with a 440 it has the stock 109mm bore and i want to increase the bore, my question is, how big of a bore can u but in the 440 rb engine. i want to put in a 5.00in. boreand a 4.150in. stroke.

[MrPbody]

That's a 4.32" bore, standard (most reference material refers to American engines of the era in inches, not metric). It is generally accepted that the big Dodge is "safe" to .060" over or 4.390". Have the block sonic-tested and the "map" will tell for sure, a minimum of .120" on the "thrust" side. .150" would be better.

There is not enough "room" to have a 5" bore in that design. Some of the aftermarket hemi blocks can go as high as 4.6", but I think that's about it.

The 4.15" stroke, on the otherhand, is quite popular and turns a 440 into an ANIMAL! We have one customer with 499 CID in a "fat tired" Road Runner, going high 10s on 93 octane with iron heads. Not bad, buit there's a BUNCH more in it. These are high-torque engines and not meant to rev really hard unless all the parts are WAY up there in quality ($$$). Rowe-man revs his to 7,200. With better heads, I'm sure it would go to 8,000, but I can't say whether or not it would "live".

Jim

[MagicRat]

If the bore is stock now, my suggestion is go for a .030 over bore, not .060.
The difference between .030 and .060 bore is about 6 cubic inches, which will not produce a noticeable power increase.
However, it will leave enough room for a second rebuild in the future, either by you (if you score a cylinder wall badly, etc) or someone else, if you sell the car in future. For that reason, IMO a .030 bored block is worth more than an .060 bore.