360 Swap In ’87 5th Ave.

Tech Question


Gid day from Canada Rick.

I’m swapping in a freshened up 360 from a 1978 Cordoba into my ’87 Fifth Avenue. It was low milage and running well, so I just gave it a re-ring kit from one of your advertisers and a locally performed (by me) valve job, back cutting the exhausts only. I’m interested in mileage and torque with this fat little luxo-cruiser’s long gears, so I purposely didn’t stick on 4bbl heads knowing I’d lose torque. A windage tray foundit’s way onto the mains for more free horsepower and friction reduction at no cost to mileage. I’ve got a question or two about the motor listed below but I’ll describe the rest of the swap first to give you a background to go on.

I’ve got to drive this car every day so I’m swapping over things gradually. I gave the computer to my Dad for future use in his or Mom’s Fifth Avenues and in went the ECU system with a Mopar Performance distributor that I purloined from his stock of parts we stripped off his ’77 Gran Fury Brougham. I installed the bigger ’78 Cordoba radiator with minimal difficulty. Next I bought a cheap non-balanced torque converter and shortened the Fury’s driveshaft, then stuck the 727 from the Fury behind my Fifth’s 318. I’ve cheated “tranny death” with the weak 999 for two years by blocking off the banjo tube in the valve body and locking out the no longer functioning lock up, thereby restoring my 3rd gear. I’ve swapped in the “catless” front pipe from the Cordoba with a low restriction muffler and 2 1/4″ tail pipe from Midas, but the Cordoba’s Y-pipe actually contacts the 318’s oil pan. Realizing that a ’78 LeBaron had a catless Y-pipe and they came with 360’s, I figured this system would clear the pan, as an ’87 Fifth Avenue is almost identical mechanically to the ’78 LeBaron.

My question is this; would my Dad’s ’77 Gran Fury Brougham’s 360 have the same oil pan as a ’78 LeBaron with a 360 ? If so, am I right in assuming it will fit inside my 87 Fifth Avenue’s K-frame ? Also am I right about the ’78 LeBaron’s Y-pipe fitting perfectly on my Fifth? Does anyone make a mondo-large single pipe to service that part? Walker used to years ago, but I know of no one who does now. As for the motor, I want max mileage and torque so do I stick with my 360 2bbl carb and manifold or swap on my T-Q and manifold? (It’s got the stock 252 degree cam).

Last question; am I missing any torque adding tricks? (Keeping in mind I don’t want to sacrifice mileage.) Next year if funds permit, I’m going to stick in a 518 O.D. tranny and maybe find a sure grip rear with a little steeper gear. I’m sure I’ll have a lot more questions for you about that later. Meantime, thanks kindly for your time.

Driving luxury and quality on the cheap, Malcolm Hamilton



First a surprise. ALL 360 heads are “4bbl” heads. Just check… you’ll find 1.88″ intakes and 1.60″ exhausts! Next, let’s talk about that “non-balanced” torque converter. Did you forget the 360 is externally balanced? Big time, to the tune of something like 20 in./oz. Get a 360 converter; you’ll find a HUGE weight! Or just get the rick B&Mflexplate.

The 4-bbl setup is a personal choice, but, for my money, the T-Q is an awesome street carb. Mileage, response, and performance in one package. Like Carter used to say: “The hot one for cool performance.” Finding a good one might betough, if so, a spread-bore Holley is the plan.

ALL 360 passcar oil pans, with the sole exception of C-bodies, are the same. Unfortunately, Dad’s “donor” Fury is a C-body. As far as exactly HOW different, I guess you’ll let us know… or, maybe, with this posted, somebody else will help us out on that tidbit. Best bet for single exhaust: get a Flowmaster 2-into-1 collector and have a local shop fab something. Minimum recommendation: 2-1/4 off the manifolds, 2-1/2″ to the muffler. Hemi muffler will fit. This is a MEGA torque adding goodie! Maybe 20ft./lbs., it’s amazing. Did you know that ’79-’80 F and M bodies had a dual system, with a REAR Y-pipe and one resonator? (Good luck finding THOSE parts!) By the way, up in Eh-land, you’re lucky on the freedom from cats on the late-’70s cars. Here, almost everything had cats after ’77 and many even before that.


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