Minor upgrade ideas that won't drastically hurt drivability or comfort.

[Kern Dog]

Hey guys,
I have considered looking into the purchase of an 80s era 4 door Mopar.
This is unusual for me...I always viewed 4 door cars as stodgy, mature, geriatric sometimes. I have a few Classics already but nothing that would be considered a comfortable cruiser.
I do like the Fifth Avenue cars but I have wondered if the choked off 318 in such a heavy car would be an absolute pig in a straight line. Now, I'm not looking to outrun my other cars....

...but I would like it to have respectable acceleration. Here in CA, due to the 1976 and later regulations, I'm bound to remain emission compliant which means catalytic converters, the stock cam and carburetor. Years back I had a 76 Camaro with headers and had to scramble to put the emission stuff back on every 2 years to keep it registered.
We may be leaving CA within a year and with the possibility of moving to a place without emission testing, the options are widening. I'm curious about what some of you have done to improve the power of your cars while not destroying the fuel economy. I have a rebuildable '74 360. I have thought of stroking a 318. Elimination of the catalytic converters and a decent 2 1/4" exhaust system were some preliminary ideas that I had. I love the ThermoQuad carburetor so I'd factor that in the build.
A stock cam, stock intake 360 would have more torque than the 318. Dual exhaust with quiet mufflers would allow power gains without a rumble.
I thought of a switch to an A-500 4 speed overdrive from a Dakota, Van or truck. Those have similar ratios to the stock 3 speed transmission but also an overdrive 4th gear. The axle gearing in the Fifth Avenues is a super tall 2.2 from what I have come across, so I thought that even a 2.76 or 3.21 gear would be fine with the .69 overdrive that the A-500 has. Final drive could still end up around 2.0-2.2.
I wouldn't be concerned with cutting out weight. I want quiet and comfort, that means padding and thick, plushy seats.
I even thought about a 5.2 or 5.9 Magnum. They have better flowing heads, they don't leak oil like the LA series engines and all have roller camshafts so I wouldn't have to risk the dreaded flat tappet failures like we all have seen on the higher performance classic engines.
Let me know what you think!

 

[Camtron]

‘86 and up come with roller cams. There’s not much in support for the FMJ platforms. It’s basically either stock replacement parts or full upgrade/aftermarket replacement parts. Much of anything outside factory suspension and you lose the nice ride, can’t do anything fun to the engine till you’re out of California. Buy one and enjoy it as is or plan out a build for when you’re somewhere without emission restrictions. I do not envy the guys who are keeping these on the road stock and trying to keep all the emission devices working properly.

 

[Kern Dog]

I've read that the stock front suspension is not the best Ma Mopar designed in terms of crisp handling. The steering geometry, the rubber isolation, the weight shifted forward all conspire to give less steering response and a softer ride.
Oddly, I'm not looking to change that.
A 150 HP 318 pushing a 4000 lb car is not adequate though. You can make 300 HP out of a real mild 360 and still have decent mileage.

 

[AMC Diplomat]

If you drop a 360 in it, and make it look dirty, old, and factory, is the teenager at the emissions shop really gonna know the difference?

 

[Camtron]

I've read that the stock front suspension is not the best Ma Mopar designed in terms of crisp handling. The steering geometry, the rubber isolation, the weight shifted forward all conspire to give less steering response and a softer ride.
Oddly, I'm not looking to change that.
A 150 HP 318 pushing a 4000 lb car is not adequate though. You can make 300 HP out of a real mild 360 and still have decent mileage.

Yea, I have a 5.9magnum in my, 5th Ave and have upgraded most of the suspension that can be aside from dumping $1,200 On new torsion bars from, FirmFeel. Start upgrading suspension, the soft cloud ride everyone likes quickly goes away, engine swapping carbed V8s and staying smog compliant is difficult…unless you gotta a shop you know and can palm some extra cash to the technician. Thats how my mom used to have to register her, Plymouth Duster in, Ventura County, lol.

 

[LSM360]

I've read that the stock front suspension is not the best Ma Mopar designed in terms of crisp handling. The steering geometry, the rubber isolation, the weight shifted forward all conspire to give less steering response and a softer ride.
Oddly, I'm not looking to change that.
A 150 HP 318 pushing a 4000 lb car is not adequate though. You can make 300 HP out of a real mild 360 and still have decent mileage.

They definitely accelerate very leisurely. Ones with the 2.2 rear end don't help. I own the Police M bodies with 2.9 rear and 4 barrel and without CATS (which I know isn't an option for you) acceleration is smooth and decent and very livable.

If you had a stock later model 5.9 out of a truck, that would pass emissions right? Put in a 2.9 or 3.2 rear and you'd have a nice cruiser.

There's lots of suspension parts available including upgrades through www.firmfeel.com.

The transverse torsion bars could have some high speed shudder and the police cars had an issue with sagging shock towers, mostly pre '88. But if it's not abused and you're not worried about high speeds they are fine. Switching to solid K frame bushings makes a huge difference in the shudder. Mine will cruise at 120mp now with solid bushings and thanks to Mark frame ties.

If you think M bodies of that era were too soft, drive a Crown Vic from that era. Even the police ones would go boing boing boing over the road especially at high speeds.

 

[Oldiron440]

I installed a 650hp 500” 440 in my Volare, it did wonders for the acceleration, but not so much on the fuel mileage end…

 

[Kern Dog]

In the late 90s When the Dusters and Darts started to fade away around here, I considered an Aspen or Volare for a project to fix and sell or to keep for messing around with friends.
There was a lot to like about them...ALL were the standard 4 1/2" bolt pattern unlike a LOT of the A bodies that had the crappy 4" pattern for every model until 1973 and even 73-76 drum brake cars still had that pattern.
Standard disc brakes in the F bodies was a cool thing too.
The hard wall of NO was always the emission limitations.
The '76 Camaro I had years ago....things were different back then. I didn't have the skills, the tools, the money or the place to have a separate 100% stock engine, exhaust system and factory stuff to swap back over so the engine in my Camaro was barely more than stock. I never got to make the car very fast. Because of that, I focused on making it handle well. It did too. It weighed less than a Trans Am but handled better.
Now with these Mopar F bodies, those can be made to handle but they will not do as well as a Mopar with the traditional front end and suspension design. The transverse torsion bar design puts more weight forward of axle centerline and the bars have too soft of a rate. The isolated K member and rear axle squirm a LOT and that transmits to imprecise handling.
I'm okay with their limitations if I'm looking for a cruiser but back then, I wanted performance.

 

[AMC Diplomat]

I don't know about "not do as well as a mopar with the traditional front end" because as I inject police parts into my build the damn thing keeps handling better and better.

And I'm sure the guys who have gone full Firm Feel will disagree

Edit:
The old clapped out Fifth Avenue in a police chase video. I think these cars handle pretty well for what they are

 

[Mikes5thAve]

Well that police chase video does show why 5 leaf springs and police sway bars are nice additions. But especially with a 5th avenue they do handle ok as is and comfort is important too.

I have 3 M bodies and 2 of them have 360s. But 318 is ok performance wise and better gas mileage wise.

 

[AMC Diplomat]

Plus most of these cars are 3500 pounds or lighter. A modern Challenger, depending on the spec, weighs more than a Lincoln Town Car. I'm not saying a Fifth Ave can beat a Challenger. I'm saying you can have a lot of fun for not a lot of money

 

[Aspen500]

I installed a 650hp 500” 440 in my Volare, it did wonders for the acceleration, but not so much on the fuel mileage end…

I can relate to what you're saying, LOL

 

[Camtron]

They handle fine at speed once all the dumb old soft rubber ISO bushings get deleted from the k-frame and and rear end. Some guys will swear by Poly bushing replacements for them, I swear by deleting the rear ISO all together and getting solid aluminum K-frame pucks. Get rid of all the jello letting the suspension walk around.
Tubular upper control arms, bracing lower control arms (because the factor stamped units flex a bunch too) and a rear sway bar really tighten these cars up to drive and handle modern traffic speeds, no problem…only issue is, that soft comfortable ride is now completely gone, lol but the car handles rock solid now.

 

[armataz]

Hey guys,
I have considered looking into the purchase of an 80s era 4 door Mopar.
This is unusual for me...I always viewed 4 door cars as stodgy, mature, geriatric sometimes. I have a few Classics already but nothing that would be considered a comfortable cruiser.
I do like the Fifth Avenue cars but I have wondered if the choked off 318 in such a heavy car would be an absolute pig in a straight line. Now, I'm not looking to outrun my other cars....

View attachment 51989

View attachment 51990

...but I would like it to have respectable acceleration. Here in CA, due to the 1976 and later regulations, I'm bound to remain emission compliant which means catalytic converters, the stock cam and carburetor. Years back I had a 76 Camaro with headers and had to scramble to put the emission stuff back on every 2 years to keep it registered.
We may be leaving CA within a year and with the possibility of moving to a place without emission testing, the options are widening. I'm curious about what some of you have done to improve the power of your cars while not destroying the fuel economy. I have a rebuildable '74 360. I have thought of stroking a 318. Elimination of the catalytic converters and a decent 2 1/4" exhaust system were some preliminary ideas that I had. I love the ThermoQuad carburetor so I'd factor that in the build.
A stock cam, stock intake 360 would have more torque than the 318. Dual exhaust with quiet mufflers would allow power gains without a rumble.
I thought of a switch to an A-500 4 speed overdrive from a Dakota, Van or truck. Those have similar ratios to the stock 3 speed transmission but also an overdrive 4th gear. The axle gearing in the Fifth Avenues is a super tall 2.2 from what I have come across, so I thought that even a 2.76 or 3.21 gear would be fine with the .69 overdrive that the A-500 has. Final drive could still end up around 2.0-2.2.
I wouldn't be concerned with cutting out weight. I want quiet and comfort, that means padding and thick, plushy seats.
I even thought about a 5.2 or 5.9 Magnum. They have better flowing heads, they don't leak oil like the LA series engines and all have roller camshafts so I wouldn't have to risk the dreaded flat tappet failures like we all have seen on the higher performance classic engines.
Let me know what you think!

if you can find one,the later 80's early 90's FWD, 5th avenue had an option for a shelby built 2+2 turbo charged 4 cylender hemi . it is the same engine in his glh models.
this is a good way to get your boost, and stay emissions compliant, if you can find one. good luck.

 

[armataz]

If you drop a 360 in it, and make it look dirty, old, and factory, is the teenager at the emissions shop really gonna know the difference?

yah, they check the VIN to verify, it's state law.

 

[AMC Diplomat]

yah, they check the VIN to verify, it's state law.

How is a teenager gonna know if he's looking at a 318 or a 360? And if he goes to read the vin on the block... well....

 

[Kern Dog]

Thanks man, but.....

if you can find one,the later 80's early 90's FWD, 5th avenue had an option for a shelby built 2+2 turbo charged 4 cylender hemi . it is the same engine in his glh models.
this is a good way to get your boost, and stay emissions compliant, if you can find one. good luck.
View attachment 52002

I am absolutely not interested in anything that is FRONT wheel drive or electric, no matter how fast it is or how good it handles.

 

[armataz]

How is a teenager gonna know if he's looking at a 318 or a 360? And if he goes to read the vin on the block... well....

sorry, that would be the block number. the vin, just gives the engine it is suppose to have.
it is perfectly legal to swap an engine, as long as it is emissions Complient to the vehicle though.

 

[armataz]

Thanks man, but.....


I am absolutely not interested in anything that is FRONT wheel drive or electric, no matter how fast it is or how good it handles.

LOL dont blame you. I would not be either .. I, just tossed it out as an option to achieve your stated goals. ;-).
I'm starting to look towards the land of OZ.
they have a lot of performance parts for my 225 slant six. I've had a really hard time in oregon finding a V8 donor car to do an engine swap. newer magnum 318-360's are common out of trucks and vans, but older V-8 cars are hard to find since cars for clunkers. and we are the home for the mopar resto show grave yard cars.

 

[LSM360]

I installed a 650hp 500” 440 in my Volare, it did wonders for the acceleration, but not so much on the fuel mileage end…

Hahaha, to heck with mpg!