What do I have to look forward to when doing this? Is it a true drop in? Car currently has a 318 mated to a 904 trans w/8.75 rear (which is stamped 2070741) Can I run the 904 with the 360 crate motor? If so, do I need a different converter? Does the trans and rear end have to be rebuilt or do I have to go with a 727? Can I use the same radiator? Do I have to make any suspension modifications?

Thanks

 

It should drop right in, IIRC the motor mounts are the same. The nice thing with Mopars, most all of their transmission will bolt right up to the blocks.


You don't *HAVE* to go with a 727. The 904 rebuild would depend on how much more power you're going with, plus the mileage? You might just want to flush it, add new fluid and a shift kit in it.



Rear end shouldn't have to be rebuilt. I doubled the HP in my Dakota and the stock rear end(knock on wood) has 150k on it and still runs fine.

 

The 318 is inturnally balanced,you will need a balanced flywheel or a balanced converter for the 360.

 

HP will probably be between 320 and 360 I would imagine, maybe 375 tops. Think the A-904 can handle that ok? I don't really want to go with the added expense and extra work of a replacement 727 transmission. Don't need a race car just a street cruiser. Any suggestions as to what I would do with the 904?

 

Can I use the same converter with a counterweighted flex plate or should I just go out and get one that is 360 specific?

 

That should be good. As for the flex plate/converter. I have a non-balanced converter and the B&M balanced flex plate from Summit Racing.

 

I did a swap like this a long time ago and I had to find the correct mounts which took a bit of time to do. The late model ears on the 360 are just a bit off.
If you rebuild your 904 with a shift kit, deep pan, and use a tranny cooler it should handle your 360 motor. Don't over heat it and you'll be fine.
You'll need that externally balanced flywheel or converter for sure.
You should have the 8-3/4 style front loaded differential in your coronet. There's still a bunch of stuff out there for those ol' pigs, and they are very tough. The thing you want to watch is the outer wheel bearings as they have end play adjustments kinda like a front wheel bearing. An old chiltons manual can give you the details, or you can swap them for sealed units that require no adjustment.