273 to 318 engine swap info please!!

[berlins]

I have a 67 Dart with the 273 HiPo and 904 automatic, anyone know what would be involved with swapping out the motor to a 84 318? Think the
engine mounts are the same but what about the flywheel, flexplate, and
exhaust manifolds or any other items??? Found a 84 318 engine someone
wants to sell and think that would have the hardened valve seals and such. My 273 HiPo was rebuilt before I got it and is a dog, thinking they
didn't do something right on the rebuild.

 

[AdamR]

everything will swap right over but you will needed either a balanced flexplate or balanced torque converter I believe.

 

[lhearold]

Should be a bolt in swap except for maybe the electronic ignition. The 273 and 318 are both internal balance so no special flex-plate needed. If need be you can use the flex plate from the 273 on the 318 if the bolt holes in the 318 plate don't match. Hardest part of that swap is going to be the water pump. You will need a newer model radiator with the outlets on the bottom pass side to match the 318 pump. To change the pump to the old style you will need to change the whole timing gear cover so you will be able to see your timing marks.

 

[66fs]

Torque convertor hub is smaller on the original "67" 904 than the pilot in the 318 crank. There might be an adapter out there. Flex plate should be good to go. I agree on the old style water pump and will add that you would also have to change the vibration damper if you swap front covers.

 

[grimreaper]

Yup, if you use the early pushbutton tranny you will need a converter spacer as the hub is smaller on the early 904. It's available from Pat Blais Transmissions 206) 365-1966 or look up TFilte Patty on E-bay.

 

[berlins]

Thanks for the info, I'm having a brain fart right now. It's been a while since I've split an
engine from the tranny but I thought the pilot hole on the crank was just used on manual
transmissions. I thought the flex plate bolted to the flywheel and the torque converter bolted to the flex plate. What goes in the crankshaft pilot hole when you have an automatic??? Seems like something should go in the pilot hole to keep everything true
under torque....

 

[66fs]

There is a larger diameter shallow hole in front of the 4 speed pilot bushing on the crankshaft that centers the torque convertor with the crankshaft.

 

[MoparJoe20]

There is a larger diameter shallow hole in front of the 4 speed pilot bushing on the crankshaft that centers the torque convertor with the crankshaft.

It will most likely have the large hub, I'm using a 9.5" flywheel from a 67 273 on a '85 318 crank, I had the seller measure it before I paid because I thought 68 was the first year for the larger hub for the flywheel/flexplate.

 

[Sedanman]

Can you just use the newer converter on the early trans or are the splines different? I'm swapping an 87 318 & 70 904 in place of my 67 273 904 & am trying to a cost effective temp swap till I can get a better drivetrain set up. The 273 has a dead cylinder & I was gifted the other motor.

 

[66fs]

Yup, if you use the early pushbutton tranny you will need a converter spacer as the hub is smaller on the early 904. It's available from Pat Blais Transmissions 206) 365-1966 or look up TFilte Patty on E-bay.

This is the most cost effective way to use the "67" and older older trans with the newer engine. I am not sure about the convertors. The "70" trans should be good with the "87" 318. It is always good to measure or mock assemble to be sure.