Changing out 318 to 340 on 73 Dart Swinger

[Artstan]

I am considering buying a 73 Dart Swinger with original 318 and tranny that came stock. I understand that without changing the tranny or rear end that I can put a 340 in the Dart. Is this true, and can I do things like change cam etc to get more hp out of the 340 above 400 hp and still not have to change tranny and really end?

Thanks! Stan

 

[Dartsun]

It all depends on what rear end your 73 dart came with to withstand the 340. If it has an 8.25 rear should be fine but a 7.25 will not last long at 400hp. Dustin

 

[Artstan]

It all depends on what rear end your 73 dart came with to withstand the 340. If it has an 8.25 rear should be fine but a 7.25 will not last long at 400hp. Dustin

Thanks so much. I will get specifics on the drivetrain. And the auto tranny should be fine? If I buy a solid 73 right, is it a good idea to put a 340 in it and try to muscle it up.. some Mopar buds act like nothing good was built in 73.. your views?

 

[Dartsun]

The 904 transmission is a good solid transmission I have no experience with one behind a 340 I wouldn't think it'd be a problem. Plenty of folks here run 904s.

 

[abodyjoe]

easy swap... will need the 340/360 motor mount or modify the 318 mount to work.. a stock 904 may not hold up to 400 hp but that 904 can easily be built to hold up without anything exotic put in to it.. like stated already the 7 1/4 if thats what it has may not live long. but if you don't put slicks on it you may be ok for a while until you can upgrade. you can also drop a 360 in just as easy as a 340. only thing you'll need is the B&M 360 flexplate..

 

[RedFish]

So does this 73 Swinger have power brakes? Does it have power steering? Neither is hot rod friendly.
Will the OEM fuel delivery be adequate ?
I wouldn't trust a bone stock engine rebuild to a OEM radiator.
Plenty of members here who have been down this road. Good luck

 

[Artstan]

It's got PS n power drum breaks. New 4 bbl Edelbrock and radiator that came stock with the car 318. What I'm hearing is updated motor mounts, radiator, rear end, and possibly carb. Is a 73 Swinger worth all this? I guess it depends on the eye of the beholder . I've had Road Runners and GTXs , which I needed the cash and sold recently, so I thought this may be a more affordable option. Thoughts?

 

[Dartnut]

It's got PS n power drum breaks. New 4 bbl Edelbrock and radiator that came stock with the car 318. What I'm hearing is updated motor mounts, radiator, rear end, and possibly carb. Is a 73 Swinger worth all this? I guess it depends on the eye of the beholder . I've had Road Runners and GTXs , which I needed the cash and sold recently, so I thought this may be a more affordable option. Thoughts?

Okay, i'll give you an opinion.
It's worth it if you want to keep the car and have fun with it.
If you are looking at it from an investment point of view, don't do it.
The only way you would recoup most if not all of your investment is if the a-body you choose is a real 340 car '71 and older.
And i may add, that you would have to get into it cheap and it would have to be a very nice car when done.
As you already know, a Road Runner or GTX is easier to sell, and for a lot more money.
Compare that to a nice 318 Satellite of the same year and the price difference is astounding.
This would be a similar comparison to a real 340 '70 Swinger and a 340ised '73 Swinger.
Given equal conditions of both cars, you would sell the '70 faster, for more money, and have a lot more interest.
Even though i personally like the '73 and up a-bodies, a lot of people don't.
I hope this helps,
Tom.

 

[RedFish]

The a-body, especially headers in the a-body, will be a whole new experience for you. it's a tight engine bay. For example, We've recently seen aftermarket braided steel conflicting with bulkhead wiring resulting in engine bay fires. But hey... If you're up for it, you're in the right forum.

 

[318willrun]

The 904 will last.... a short time before it starts slipping in 2nd gear behind a 340/360. the 904's are tough --- if a few upgrades are done.
If your looking to save money, and do not have the 340 yet, I'd either use a 360 or work with the 318 as a 340 can be expensive. Have you considered a 360 magnum? Just adding a 4bbl and headers to one never disassembled but runs good is 300 hp. These are fairly cheap and easy to get. EQ heads (1k) and an upgraded cam can get you 375-400 hp.

 

[Sedanman]

They are running 904's behind big block drag cars now so I'm pretty sure they can handle what a small block can put out with some mods

 

[Artstan]

Okay, i'll give you an opinion.
It's worth it if you want to keep the car and have fun with it.
If you are looking at it from an investment point of view, don't do it.
The only way you would recoup most if not all of your investment is if the a-body you choose is a real 340 car '71 and older.
And i may add, that you would have to get into it cheap and it would have to be a very nice car when done.
As you already know, a Road Runner or GTX is easier to sell, and for a lot more money.
Compare that to a nice 318 Satellite of the same year and the price difference is astounding.
This would be a similar comparison to a real 340 '70 Swinger and a 340ised '73 Swinger.
Given equal conditions of both cars, you would sell the '70 faster, for more money, and have a lot more interest.
Even though i personally like the '73 and up a-bodies, a lot of people don't.
I hope this helps,
Tom.

Thanks very much to all of you for the great thoughtful explanations. Stan

 

[Artstan]

Thanks guys for the great help!!!