I'm planning on swapping my slant six for a 318 on my 63 dart gt w/push button auto. Can I drop in the 318 and use my original 727 or should I upgrade to a 904 . Any suggestions or recomendation would greatly be appreciated
63 Dart used a 904 trans. A 727 is the bigger trans. Stay with a 904 trans, behind the 318, but it needs to be the V-8 unit, the slant six trans has a different belhousing then the V-8 trans. If you want to keep the PB shifter, you must use a 1964 V-8 904 trans. The other option is a 65 V-8 904 trans with a 64 valve body. You can keep the original driveshaft. Next option is a 66 newer V-8 904, but that requires a PB shifter unit modified by Imperial Services (expensive), and a different driveshaft.
Keep in mind the hole in the end of the crankshaft and the converter changed between 1967- and 1968. If using a late trans, you must have the late crankshaft or a custom made converter. If using a late crankshaft and a early trans, just get an adapter bushing for the crank (cheap).