Rebuilding an early Hemi engine

[[Image:early_hemi_bored.jpg|right|thumb|300px|An "Early Hemi" engine being bored at the start of the rebuilding process.]]

It will cost 2 to 4 times as much to rebuild an early Hemi than it will your everyday small block Chevy. This difference in price has been the cause of many a Hemi just sitting in the corner of a garage somewhere instead of rumbling down the street in all its glory. However, it is very rare to find an early Hemi in a wrecking yard that can't be rebuilt. Chevy and Ford fans aren't so lucky.

After price, the second item you need to be concerned about when rebuilding a Hemi is parts availability. Stock rebuild parts are widely available. However, performance parts for some of the less popular Hemis can be a real challenge to find. Epecially the DeSotos -- performance parts for these motors are virtually non-existent. Some factory equipment was supplied way back when, but it's very difficult to come by, and quite expensive. For example, a DeSoto factory dual quad manifold with carburetors and linkage intact could fetch $2000 or more. Limited performance equipment is available for the Dodge Hemi, but far more parts are available for the Chrysler 331-392 series than any other. The good news is that as these engines are being rediscovered and as they become more popular, manufacturers are beginning to re-introduce performance parts they stopped making 20 or 30 years ago. Newer companies are providing parts and services for the early Hemi enthusiast, and more are sure to follow.

Each Chrysler division (Chrysler, Dodge, DeSoso, and Plymouth) produced their own version of the Hemi. Only a few specific parts will interchange, including the following:

*Dodge high block and DeSoto high block connecting rods will interchange.

DeSoto and Dodge heads won't interchange between high and low blocks without spacers and a lot of extra work. The manifold mounting angles are different between high and low blocks so swapping heads can be a nightmare on these motors when it comes to finding a compatible intake manifold. This is especially true with the DeSotos because of the lack of availability of any high performance aftermarket manifolds. The Dodges can use a log manifold to solve this problem, if you can find one.  

*Chrysler 331 hemi heads can be used on the 301 and 331 polys, and 354 Hemi heads can be used on 354 polys.

*No camshafts will interchange between low and high blocks of any engine family because of differing lifter bore angles.

 

I recently discovered that the low deck dodge early hemi (241 and 270 CI) will accept a later small block distributor with no modifications.  This may be true of the other dodges, but I do not have one to confirm with.

The '51-'53 Chrysler 331's (and some of the '54s) had an extended belhousing cast into the back of the block, which limits transmission choices. Some outfits have reintroduced adapter kits which allow the GM 4-speed to be bolted to these blocks. These adapters are a welcome addition to the parts bin for many enthusiasts. For years, these extended blocks were considered useless (except for spare internal parts) and many of the blocks were trashed by shortsighted hot rodders. DeSoto, Dodge and Plymouth never produced Hemis or polys with the extended bellhousing.

 

In '54, Chrysler fell in line with its other divisions and introduced a more conventional belhousing design, making the installation of modern GM and Chrysler automatic transmissions much easier. However, adapters are still required; they're available from several sources, but be prepared to pay between $300-$400 for a good one.