'64 Dart GT: 273 to 325 swap ?

[my7tb]

I'm interested in swapping the 273 in my '64 Dart GT. Would the 4-speed and the engine compartment accept a '57 325 poly / hemi ? Has anyone done this ? If so, what were the snags / concerns. I'm thinking if it did fit, block hugger headers would be needed. Please help. Carey

 

[mcnoople]

Sounds like a lot of work for little gain. Parts are harder to come by. I believe the engine is heavier. Other than the "cool" factor what is the motivation. Do you have a 325 just lying around looking for a home. That is not a common motor.

 

[slantsixdan]

Er-ruh…why do you want to do this? If you have a 325 in good condition, someone will happily buy it with funds that will go well towards a nice buildup of whatever 273-318-340-360 you might care to dream up.

With a good selection of Sawzall accessories and enough welding rods, you could certainly do this swap. Add extra money and time for the bigger brakes and suspension upgrades you'll need to make the car manageable with its screwy new front/rear weight distribution. Remember, the LA engine, of which the 273 was the first, was made smaller and lighter than the previous polyspherical-head engine with the immediate goal of fitting and working well in the A-bodies. There is nothing such as a "poly/hemi" engine.

 

[RustyRatRod]

The 325 shares the bellhousing bolt pattern with the small block.....BUT the dowel pins are in a different location. Pretty interesting swap idea. Can you post pics of the 325? We can tell real quick whether it's a Hemi or Poly. Either way, it would have a lotta cool points. Would be some work, no doubt, but you'd have something different.

 

[Hell_Fish]

There is nothing such as a "poly/hemi" engine.

241 and 270 shared the blocks between poly and hemi. :glasses7:

 

[Rocket-Racing]

I would also have to argue that there is such a thing as a Poly/Hemi engine if speaking in terms of what engine to use without having bought it yet.
Some of the engines were made as both Poly and Hemis. I have a '56 270 Poly myself. Swapping heads would make it a 270 Hemi..

And for the record, I would not put a heavy 50's engine in an A-body. It will be a lot of work, make the car handle bad without massive upgrades and will not perform like a hot smallblock

 

[slantsixdan]

I would also have to argue that there is such a thing as a Poly/Hemi engine if speaking in terms of what engine to use without having bought it yet.

Post some pics of a 325 Poly/Hemi engine, please.

 

[my7tb]

I understand that the 273 was made as a lightweight V8 for the compact Darts in '64. It was made from some 318 poly parts, and if I remember right, the '64 4-speed trans would also accept the 318 poly. Knowing this, I was wondering if the '57 325 block would also mate to it. I said "poly/hemi" above because the 315 & 325 blocks and intakes could be used with either the poly or hemi heads. It's a shame, but the car sat in the weeds for a few years, and the frame rails got soft. Rather than having them completely replaced, I thought I'd box them and go the nostalgia route, with leafs and a straight axle. The car is too far gone for a concourse restoration. So, I've decided to rod it a little. And, yes, I'd be after the cool factor with a small early hemi. Of course, upgrades would be done to the braking system as well. I'm just wondering how / if the 325 would fit, mate to the 4-speed (spline issues ?), etc. Alright then, if I do decide to go with a built small block LA instead, what are those suggestions ? Thanks for your help all ! rayer:

 

[slantsixdan]

I understand that the 273 was made as a lightweight V8 for the compact Darts in '64. It was made from some 318 poly parts

Nope. Clean-sheet design. No 318 poly parts in a 273 except perhaps the odd nut, bolt, or screw.

 

[Hell_Fish]

Only parts the same on the poly 318 and 273, as I recall are the crank and timing cover. I like the idea of a hot rod dart, but the hemi should be in a open hood early teens to 30's car were it can be seen. A 360 would be a better choice and race friendly.

 

[bamacuda]

I prefer chocolate glazed donuts, myself!

 

[Tincup]

I have a buddy of mine with a 2 x 4 barrel intake for a poly motor. Unfortunately it's not for sale, he wants to build a rat rod and put that in it. ( It will never happen! )