engine help

[Wogden]

I must confess that I do not know much about the Mopar V8's so I am hoping someone can enlighten me and I can assist a friend that is building a early 30's Chrysler. He is looking for a early 273 ci engine, a 318 or a 340. Can a 273 be bored to 318 or to 340? Are all of these compatible with the 727 trannies. Was the 360 it's own platform or is it a punched out 340?

Which would be the easiest to find and which is most likely to cost less to rebuild?

Any other comments would be appreciated. Thanks Walt

[JACK M]

What ever you decide, the engines are all balanced differently and require different flywheels. You would be best to find a donor car that has all matching parts.

The 727 trannys will be interchangable as long as it is for an 'A' block but make sure that you use tha correct converter.

Mopar has an engine book in their performance catologue that explains all this.

You will most likley have to do something with the steering box too as they are usually on the inside of the frame and will not clear a V engine.

[Rusty_OToole]

A brief history of Chrysler's A engine. Plymouth got a brand new engine in 1955 not related to any other engine. It debuted at 277 cu in but by 1957 was enlarged to 318. This was the base V8 for Dodge and Plymouth for years, it had distinctive wide heads with scalloped lower edge on the valve covers and staggered valves like a Chev big block. This was called the A engine.

In 1964 they needed a narrower engine for the compact Dart and Valiant so they made the 273. Basically a 318 with 1/8 smaller bore and different heads. They even used the same crank, and extra heavy piston pins to make up the weight of the smaller pistons so they did not have to rebalance the crankshaft. There were other unique features to the 273 such as solid lifters, and adjustable rocker arms. This was the basis of the new design of 318 made from 1965 on. It was called the LA engine.

Chrysler's strongest engines were the B big block, 413 426 440 etc. Unfortunately this block would not fit in the small Dart, Valiant, or Barracuda body. So in 1968 they introduced the 340. This was a souped up 318. Bored out cylinders, new big valve heads, cam, Thermoquad carb etc it was the hottest small block of the time. The 340 Swinger was nearly as fast as a 440 Road Runner at the drags, in fact if the Road Runner driver was not on his toes the 340 could take the lead.

A few years later they needed a "smog" motor. Something with lots of torque, cheap to build, and reasonably economical for their full size sedans. So they took the 340, gave it a smaller bore and longer stroke, put in smaller exhaust valves, detuned the compression and cam and made it into a 360. The 360 is the only one of the family to be externally balanced and therefore requires a special flywheel or torque converter. Chrysler dealers sell a balance weight that can be welded on to a torque converter.

All these engines are related and some parts will interchange while others are unique to a particular engine. Generally speaking you can put any LA engine in where any A or LA engine used to be. They did relocate the motor mounts at some point but you can buy special mounts aftermarket to put the newer engine in the older chassis. Or just grind off the mount and weld it on an inch farther forward.

It all depends what you want to do. A 273 block can be rebored and rebuilt but it can't be bored 1/8 to turn it into a 318. But there are millions of good 318 blocks out there.

Easiest and cheapest to find would probably be a 318 out of an 80s Fifth Avenue sedan. These were very reliable long lived engines and seldom got abused in a Fifth Avenue. You could probably pull one at random out of a junkyard and it would run fine. If you were pernickety you could buy a cheap overhaul kit and put in new rings, bearings, timing chain, and have the heads redone and get another 100,000 miles. Many of these came with automatic overdrive trannies.

An A or LA engine will only fit an A or LA transmission. Also in the early 60s they changed the flywheel/engine/transmission interface so it is best stick with "all early" or "all late" configuration. The changeover year is around 1962 so this is a problem that seldom crops up anymore.

For a heavy car the 360 is a strong motor. A cam, intake and headers will really wake one up. They were very detuned from the factory, one of the old time "smog" motors. But the basic design had a lot of unused potential.

The newer "Magnum" motors from 1992 up were very much redesigned, more efficient, more powerful, more economical. Came with roller cams and fuel injection. But only installed in trucks and vans.

Since you do not state what kind of car you have, what you want to do with it or anything else that is about all I can tell you offhand. There are Mopar websites that go into a lot more detail. I recommend Allpar or Mopar Action magazine web sites.

Edited January 20, 2011 by Rusty_OToole (see edit history)

[Rusty_OToole]

It breaks my heart to say this but a Chev 350 would probably fit easier. I helped a friend put a 340 in a 1937 Plymouth coupe years ago. The starter and exhaust were a headache because they hit the steering or frame. We had a Chev engine lying around and test fitted it, it fit much easier and nothing hit anything.

If the starter hits the frame or steering you can use a Japanese starter that is much smaller than the old Chrysler model we had. It was first used in the early 90s and it is probably the most common one to find these days.

[JACK M]

OH NO ! !

Never put anything but a Mopar in any DPCD.

The small block Chevy is a cop out and just plain wrong......

You probably need better suspension anyway.

No offence to Rusty.

Edited January 21, 2011 by JACK M (see edit history)

[Wogden]

Wow, now there is a history lesson! Thank you for all that info. It will help us immensely I am sure. The steering box clearance is not an issue as there will be an IFS installed with a rack. The exhaust we will have to work on when we get there. Thanks guys for the input.

[keiser31]

Since the steering box is not an issue, we implore you to keep it all MoPar! And good luck on the project. We would LOVE to see photos of the car. Oh yeah....I have the original stock 273 two barrel in my A100 pickup and it still burns the weenies off of it when I want it to.

Edited January 21, 2011 by keiser31 (see edit history)

[Rusty_OToole]

I note you are talking about an early 30s Chrysler. What happened to the original motor or dare I ask?

[Rusty_OToole]

For a heavy car like a Chrysler a 360 might be best. There are thousands around in pickups and vans if you can' t find one out of a car. I have a 1992 ambulance in my yard that starts and runs like a champ even with 200.000 miles on it. It came with the heavy duty engine with 4 barrel and automatic overdrive transmission. Such a combo would work great in your Chrysler. The newer Magnums are even better but then you get into more electronic controls, fuel injection etc.

[Wogden]

UPDATE: Thanks guys for all your input. To clarify a few things......the vehicle is a 31 Chrysler coupe, not a large vehicle by any stretch of the imagination. My friend just emailed me that he purchased a early 273 Commando engine and a 904 trans from a collector that has had it stored for some time. Came complete less alternator and with the four barrel carb. This will make a great additon to this coupe and he is thrilled at the acquisition. Says it is a very clean engine and is in great shape. The seller said it is a 250 hp engine. Wonder what they came out of originally?

[keiser31]

UPDATE: Thanks guys for all your input. To clarify a few things......the vehicle is a 31 Chrysler coupe, not a large vehicle by any stretch of the imagination. My friend just emailed me that he purchased a early 273 Commando engine and a 904 trans from a collector that has had it stored for some time. Came complete less alternator and with the four barrel carb. This will make a great additon to this coupe and he is thrilled at the acquisition. Says it is a very clean engine and is in great shape. The seller said it is a 250 hp engine. Wonder what they came out of originally?

It could have come out of a Barracuda.

[NTX5467]

The 273 4bbl Barracuda engines were rated at 235 horsepower at about 5000rpm. IF it's an earlier version, which it probably is, there are some unique things about this engine in the intake manifold bolt pattern area.

IF the steering column is a close-fit, the left hand manifold from the earlier A-body (which it might already have), as the 340 exhaust manifolds do on the left hand, have a definite raised-angle to clear the steering column of those A-body cars. On my '80 Newport "R-car", the left hand manifold is contoured to miss the steering column. The 273s only came in the Valiant/Barracuda/Dart(compact) A-body cars and the Belvedere/Coronet B-body cars. The 4bbl versions were only in the A-body cars, usually Barracudas, though.

Having the Mopar Performance, or earlier "Direct Connection" V-8 Engine Book is a GREAT resource for all things "Chrysler V-8", even if you don't plan to do a race engine. LOTS of good info in the Allpar.com website, too.

Keep us posted on the progress!

NTX5467

[bigaadams]

IF you are looking for a 318 with OD..the cars never got that set up, only the truck...(88 and up) be sure to get one coded RH for rear wheel drive, hydraulic shift so as not to have to get into wiring the electronic controller in, with the early units you have just the OD lock switch to mount........to keep the RPM's at cruise on the 5th Aves..the 2.32 rear ratio was Chrysler's answer..that was why these cars felt a bit anemic on take off..

the 360 does not share the crank..also if you chose a 360 and automatic..bear in mind that it is externally balanced and will not interchage dampers or torque converter with the other small block...(you can add weight to balnce the other 318 converters with the aftermarket Mopar kit)

very early 273 heads will not interchange with later 273's and 318 due to the angle the manifolds bolts are drilled... even withthe LA's physically the same dimension, unless you just happen to have the 273 on hand..I would not go out of my way looking for one..unless it is the formula S version that was the HP version at 270 HP...

and as the 350 engine..only advantage you have there is the short water pump..that is why it is such a popular swap..fewer needs to modify fire wall and or relocated radiators..it cost more money to build a 350 to match the HP and life span of the similar built 360..Summit Racing proved the superiority of the Mopar over the Chevy and Ford years ago..the poor valve train of the Chevy is the main cost in the upgrade..

Edited January 28, 2011 by bigaadams (see edit history)

[Guest Noodles56]

I dropped a 1964 Chevy 283 in my '56 Plymouth and all we had to do was fabricate two mounts on the cross member and I front mounted the 283. Wasn't very hard and everything clears no problem. I know it's blasphemy for the hardcore Mopar guys, but it's true hot rodding in that it was all I had laying around and very little cash.

Edited February 15, 2011 by Noodles56 (see edit history)