65 Dart 273 to 340 ?

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bargeahead

bargeahead

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Instead of having my 273 Charger engine rebuilt what is the chance of a 340 dropping in place and bolting up to the 904 ? Were there any bolt hole changes made to the 340 thru the years? I couldn't find this specific topic but if I missed it...sorry.
THX
 
The 340 will need different engine mounts. It will bolt up to the 904 AT, but the 904 will need to be built to handle the 340. Otherwise, the 340 block is the same dimension and bolts in the same way the 273 does.

Two thoughts, which are just thoughts:

1) 340's aren't exactly easy to find, and a 360 is cheaper to find and will make more power.

2) the 273 is a pretty unique engine, and is worth keeping on that alone.

That said, its your car, and you need to be happy with it.
 
Thanks for the input. I'm exploring options. I like the idea of keeping the 273 if for no other reason it's original. Otherhand, I always wanted a 340 Cuda right after a 69 Roadrunner. They ain't gonna happen. THX again.
 
Also check your driveshaft. I believe the 65's had a ball annd trunion front joint and not a standard u-joint. The ball and trunion may not hold up to the power.
toolmanmike
 
You will need to weld a triangular shaped piece to your right motor mount Then drill it through so the new tab allows you to catch three of the ears on the 340 block. A few washers will take up the slop in the left side mount. If you use the pulleys and such from the 273 it makes the swap easy. The cast water pump puts the radiator hose in the proper place. The 904 will handle the 340 (if driven within reason) but you should consider a fresh build with a Transgo TF-2 kit and maybe Alto red clutches and Kolene steels. The hub diameter for the torque converter is different too. They went to 1.81" in 1968. You can get a bushing to adapt your torque converter from TorqueFlitePatty on E-bay or put a 68 or newer input shaft in your tranny and use a 68 or later converter.The main issue you will confront will be the exhaust. Headers (TTI or Dougs are expensive) (Spitfire shortys can be tough to get) are one solution. Keep the 273 manifolds. (Chokes up a 340) Or figure out an alternate route......
The ball and trunnion front U-joint has held up for me in various situations. (After all they held the Hemis in heavier cars)
If you have more questions PM me. I did more than a few 340 into 64-65 Barracuda swaps back in the day......
 
Grimreaper makes a good point on the exhaust. If you have power steering, power brakes, and A/T like my '64 Barracuda, you have no exhaust options, only factory manifolds. It's a tight fit!
 
Many thanks for everyone's comments/advice. It sounds as though I'll be keeping the 273. Tranny rebuild is in the works, just trying to schedule and do all with one pull. $ for the engine is only delaying factor now.
Again, input is greatly appreciated.
 
340 Heads using 64-66 "A" body drivers side exhaust manifold needs to have clearance ground on the bolt boss on the bottom of the head. Not sure about "X" heads but had to on my "J" heads. Trial fit first, it's a lot easier with every thing apart.
 
If I'm not mistaken,The early small blocks {67 and earlier I think}had a smaller crank register for the converter hub.Someone on this website sold me a spacer to take up the difference in the crank, but I ended up going with the four speed.Was the best drivetrain choice I made,because pedal cars are much more fun !! :burnout: 8) . . . . . and yes exhaust choices are a big factor
 
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