360 in a ’40 Coupe

Tech Question

 

Lars Ivar Kvissel, Elverum, Norway, 1940 DeSoto Custom Coupe

Hi Rick! I have a 1940 DeSoto Coupe wich I have owned for 30yrs. Got it for free when I was 17! Now for my dilemma. I`m in a process ofrebuilding a 392 Hemi to put in it, but for this summer, due to budgetproblems, I have to use a 360 2 bbl I have had for years. Will any 904 transmatch the 360? I`ve been told it has to be a 904-998 or 999 if its going tobe OK. I have a rebuilt 904 from a 318 on hand, but been advised to turn itdown if it`s not from a 360. Others tell me otherwise!

 

Lars:

First off, I will assume you mean a dead-stock A-904-A from a 318 car, notone that had been “built” (read: beefed or modified), since there isabsolutely no problem building a 904 to withstand anything short of anuclear holocaust, with enough money invested in “race” internals.

If it is dead stock, I think, if you just cranked up the line pressure 3 or4 turns, or, even better, invested a few bucks in a shift kit, it would livefor quite a long time. Of course, this guess assumes that the transmissionis in good health now!

Just remember to use the correct external-balance-360-weighted torqueconverter, or weld the weights on, or use a pre-balanced drive plate. Alsoremember that, for balance-specification reasons, there were two basicgenerations of 360s: 1971-1992, and 1993-up. If yours is an originalcarbureted engine, you can be sure it is the early variety.

Now, I know you didn’t ask this, but, overall, I am against the 392 swap.While the “eye candy” aspect is hard to argue with, you’ll just be adding SOmuch weight over the nose of the car, needlessly so. How about a “built” 360(425-450 HP is so easy), or even a big block? Gotta have a Hemi? OK,junkyard 5.7Ls are now plentiful — and cheap. You could even build that 904to live behind the 5.7L!

Rick

Comments are closed.

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Accept Read More