Compare the location of the...
Compare the location of the oil filter housing on Jim Weems' six-packed Cad to the photo of the stock Cad spot. He moved it to the firewall to better showcase the engine.
Racers also discovered the potential of the Caddys, with these engines showing up in various drag and dry lake cars, and also in a number of high-performance boats, although the list of famous racers using Cads is much shorter than with the Oldsmobiles, which were cheaper to obtain and for which the aftermarket offered much more hard-core speed equipment. You can look through your dusty stack of '50s and early '60s car 'zines and find many a street rod or F-100 pickup featured with high-torque Caddys between the framerails. Iconic rods such as the Kookie T and Roth's Outlaw popularized the Cad's street cred, and by 1957 there were enough really nice examples on the road to prompt Rod & Custom Editor Spence Murray to run a whole section in the magazine on six Cad-powered rods (January 1957).
Cadillac engines today
Make no mistake, we are definitely fans of all the pushrod OHV Cadillac engines, including the behemoth 425-, 472-, and 500-inchers of the later years, but for our purposes in this engine series, we're concentrating on the original 331 and its younger brothers, the 365 and 390.
If you want to run dual-quads,...
If you want to run dual-quads, as some Eldorados were equipped, you'll find intakes at the swap meets, like this Edmunds. You'll have to source out old carbs or use adapter plates to fit later four-barrel carbs.
Obviously the 390 engine is the newest of the three Cad engines, and was offered in higher horsepower levels, but all the Cad engines will work great in any size/weight street rod. There is a fair amount of vintage Cadillac speed and dress-up equipment out there at the swap meets, as intakes, cams, finned valve covers, etc., were made in some quantities back then. The Eldorados had factory dual-quad and 3x2 intakes, but they are rare, very heavy iron and today are sought out by restorers. The aftermarket aluminum parts can save more pounds than Jennie Craig. You can still find good aftermarket intake manifolds out there. Edelbrock, Edmunds, Offenhauser (see Exeter Auto Supply), and other companies made them, with many being the 2x2 design, but Offy made 2x2, 3x2, and 6x2 log-type intakes. Luckily, all the engines we're examining take the same intake manifolds.
The correct rebuild parts, individually and as kits, are widely available from Egge, Speedway Motors, and other vintage engine parts companies. Any competent engine machine shop should be able to inspect your heads and block for cracks, then deck, bore, and otherwise make true the major surfaces and assemble the engine, leaving you to add the cool stuff you've been gathering from swap meets and eBay. The 390 engines had better breathing heads, and these were commonly swapped onto earlier engines in the old days, although Cads were noted for their grunt rather than high-rpm activities. Cams are available from Iskenderian and SLR Cams. Moon and O'Brien Truckers have finned valley covers, and good old Offenhauser still makes their finned-aluminum valve covers.
The oil has to flow back into...
The oil has to flow back into the timing chain area of the engine, so Jim neatly plumbed a copper line to a fitting on the block.
The physical dimensions of the Caddy motors are similar to the other vintage GM V-8s we've already looked at, with weight at about 600 pounds and a rear-mounted distributor. Some applications will require a firewall recess to accommodate a Cad, but the end justifies the means. Transmission swaps have already been addressed long ago by our friends at Wilcap, who offer adapter kits for Cads to early Fords, GM automatics, modern GM four-speeds, and a cool setup that allows the use of a small-block Ford bellhousing and a T5 five-speed. Identify your prospective Cad motor by the bellhousing: if the bellhousing is cast in at the back of the engine, it's a '49-54; from '55-62 the back of the block is flat and the trans has the bellhousing. Original Cadillac stick bellhousings are rare and pricey, in fact so are the engines.
We can't speak for everyone, of course, but all the real motorhead hot rodders we've ever known like to open their hood and show off their engine, and in the old days the engine and engine compartment were often the only detailed and finished part of the rod. Opening your hood at a modern car event and showing off another 350 won't get much attention, but the same vehicle with a Cadillac or other vintage engine will get onlookers approving, talking, and asking questions. Such is the current state of vintage engine interest, and remember the Cadillac slogan: "The standard for the world."
Three-bolt Cad engine mounts...
Three-bolt Cad engine mounts can be easily made with cut and welded plate to fit biscuit frame mounts, but check the nicely folded and chromed one-piece mounts on Mickey Himsl's '22 T roadster.
We've never seen one of these...
We've never seen one of these vintage cast-aluminum Cadillac engine mounts for hot rod use, but it was a cool find for this almost-finished Deuce five-window.