The Mighty Hemi

From DeSotos to Funny Cars, Chrysler’s Hemi has powered them all

Who would have guessed that an engine introduced in 1951 would still be relevant more than 60 years later, powering a generation of classic American muscle cars and hot rods. The engine is none other than Chrysler’s classic Hemi, an engine considered by many to be the finest engine ever mass produced. The ‘Hemi’ moniker stands for the hemispherical combustion chambers found in the cylinder head of the motor.


The years after World War II presented various challenges to auto engineers. The major one was how to increase power without increasing compression that would result in having an engine that would require high octane fuel. Back in 1951 the quality of available fuel was poor, restricting engineers from building engines with enough compression for maximum performance and fuel economy. The answer reached was to bolt on hemi heads which would increase thermal and volumetric efficiency. The heads would also provide a low surface-to-volume ratio, minimizing loss due to combustion chamber deposits. The design had been around since at least 1904 but had never been put into practice due to higher costs.

The two Chrysler design engineers of the Hemi, W.E. Drinkard and M.L. Carpenter designed a pushrod, valve-in-head, V-type 8 cylinder engine with a displacement of 331 cu. in. It had a high (for 1951) compression ratio of 7.5. Bear in mind is that the 331 ‘Firepower’ Hemi was at the infancy of V8 engines, designed to replace the existing L-head in-line 8 cylinder found in other Chrysler models. These early V8’s eventually grew in displacement to 392 cubic inches. There are three distinct engines now commonly referred to as the ‘early Hemi’s’, each different internally and externally. The Chrysler engine was the Fire Power, the DeSoto was a downsized Fire Dome and the Dodge had the even more compact Red Ram and Super Red Ram. Although they all look similar and share prominent design characteristics they are all quite different from the later 64-71 engines.1971-plymouth-hemi-cuda-engine

If you are looking at one of these engines for power you should stick with the Chrysler engines as they seem to have more speed parts – new and used. The ‘baby Hemi’s’ from Dodge and DeSoto present more challenges in finding parts. The good news is that their lack of popularity also makes their engines lees expensive to obtain. The DeSoto engines were in fact more favored by early builders of street-driven T-buckets, A-bones, highboys and customs because they were plentiful, potent and cheap. Although stock replacement parts are still available today you will  have to scrounge swap meets or eBay for hop-up goodies. Beware though, the engines may be cheap to buy but they can be expensive to build.

The early Hemi won at Daytona, Sebring and dozens of NASCAR races. In 1965 it even powered the World Land Speed Record car ‘Goldenrod’ to a speed of 409.227 mph. The engine was four in-line Hemi’s with a total capacity of more than 29 litres and approximately 2,430 hp!! Chrysler actually stopped production of the Hemi in 1959, complaining that the engines were too expensive to build. That decision was reversed, thanks to the folks at NASCAR, in 1964.


If you’re restoring a classic car, we have used rims for sale for many different makes and models. We have a large inventory of classic hubcaps for sale as well for those looking to restore an antique car to its original specifications.

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