Hi guys I've got a 1966 Dodge Coronet with a slant six and was thinking about swapping in a 318 but was wondering do I have to put in a period correct poly 318 or can i get a newer engine to bolt onto the 3spd transmission its already got.

 

Bolt patterns are the same, but, I don't know if the engine mounts will be in the same place between the six, and the v-8. Gonna try and stay with the fuel injection from the newer motor, or go carb?

 

It's been a long time since I swapped an engine in a poly head era car. I'm pretty sure the K frame is the same. Definitely change the motor mounts. Keep in mind this is the first year for linkage to the shifter. Before this, you had a cable. While the column shifter was a PRNDL lever, it was still the cable from the older push button transmissions before 1966. This was also the first or second year with the parking brake on the rear wheels rather than the tail shaft on the transmission. Personally, I'd see if I could find a 241/270 Red Ram Hemi. Not much more powerful than the polyheads but it has a visual appeal that most engines can't match.

Somewhere I have a book from Mopar Performance that detailed what you need to drop X engine into Y car.

 

I pretty sure the /6 K frame is different, K frame itself is the same but the brackets(motor mount) welded to it are different. Keep in mind anything from that era will have to have head work done due to not having hardened valve seats in the heads. Running them with today's gas the valve will wear it's way into the head. Not sure what your preferences are but possibly a 360 magnum(carb set up)with a 727. Should not be hard to find or do.

 

A lot of Mopar valves are sodium filled. I've only had one valve seat erosion on a car of mine over the years. I suspect that one was due to FOD getting caught in the valve and starting the process. Unless I'm racing or towing, I don't bother with hardened seats until I rebuild an engine.

 

Well back when we had leaded regular i was driving with a rebuilt 383 with 906 heads(non hardened valve seats. shortly after they got rid of all lead in regular so had to use the non leaded stuff. When i removed the heads when i swapped motors the valves where worn about a 1/8 into the heads!( i still have the heads somewhere I'll see if i can find them and post a pic) If you drive it only on weekends/nice days then you may get away with it but any real driving will wear the seats down. There are now lead substitutes you can add to the gas but don't know how well they work.

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