The early Hemi's were a pretty respectable in their day, and a lot of vintage hot rod and even new tech can be applied to acheive very respectable HP and torque for their displacement. The HP and Torque your talking about may be possible to achievable out of a 331 but chances are it won't be streetable or last very long.

I have a little advice for what it's worth if you are looking for an early hemi. Chrysler made 13 diffrent displacement Hemi's from 1951 to 1959. There is almost no interchangability between the Dodge, Chrysler and DeSoto versions.

1. Unless your doing a restoration stay away from the Dodge and DeSoto versions. These are not well supported by the aftermarket and parts can be very hard to find and VERY expensive when you do.

2. Likewise I would avoid the 51-54 331 Hemi's. First they have an extended bellhousing which limits the transmission options to either the original transmission or if you can find an one, Offenhauser transmission adaptor for an early ford transmission. Additionally they have a small valve head (compared to the 55 and latter engines) without the front and rear water outlets resulting in a very limited number of intake manifold choices.

3. The 1955 331, 1956 354 and 1957-58 392s are your best choice as far as parts availablility. Besides car and truck engines don't overlook the industrial versions of these engines (mostly in the 331 and 354 versions. While generally lower compression (no big deal if your going to bore them anyway) they are virtually the same as their passenger car counterparts. Stay away from the marine engines though, as most have extra water passages in the front of the block which do not allow the use of standard passenger car timing covers water crossovers etc. Some are also reverse rotation.

Finally do to a lot of ignorance out there about the early hemi, do you research to know what your buying. (I actually saw a guy buy a 331 industrial Hemi once because he was told and believed that it was a 426 Hemi). I would do a google search for "Hot Heads Powerplay" and go to that site and download their Hemi identificatin charts before you go shopping.

Hope this helps.