Correct Mechanical Fuel Pump AMC 68/69/70 390 ?

Electric or vacuum wipers? For 69-70 and electric wipers the original pump was a Carter M-4656S. For 69-71 with vacuum wipers it's Carter M-4657S.

68 was different.  Carter M-41825C with electric wipers and MPF-4336SA with vacuum, though I think the differences are minor... perhaps just position of the inlets and outlets.

The modern replacements for the M-4656S all seem to be made by the same company now, no matter which brand you buy, and they are problematic.  The internal design is different from the original Carters and the oil seals on the new pumps frequently give out.  I have a separate thread going on this subject where I have been trying different things to resolve this.  If you're going to use a new pump I recommend you glue the seal housing in with JB Weld and drill out the oil vent holes.  See page 4 of my thread for more details.

http://theamcforum.com/forum/fuel-pumps-wth_topic80356.html

McRobb Performance Products also make a nice replacement pump, but it is fairly expensive and does not look like the original.  That's what I would use if originality is not important.

Here are a couple of possibilities for the kits.  I'm told that the X-cast pump used in many of the late 60s V8 Mustangs uses the same rebuild kit, though I haven't verified that personally.  Then & Now (see link below) would probably know or might even have the exact kit for the M4656-S.

http://www.ebay.com/itm/AFP-67-Mustang-AMK-Products-Carter-Fuel-Pump-Rebuild-Kit-Boss-302-Boss-429-428CJ-/381802356099

http://then-now-auto.com/fuel-pumps/

Also, keep in mind that there is a fuel pump with the number 4656 used on early Corvettes.  I think it's made by AC and I don't think it's the same pump as the Carter M-4656S,

The difference between 68 and 69 pumps are 68 has filter in bottom of pump, 69 the filter is at the carb.

401MATCOUPE wrote: The difference between 68 and 69 pumps are 68 has filter in bottom of pump, 69 the filter is at the carb. The original 68/69 Carter pumps all have 1/8" NPT inlet and outlets, the Carter performance version has 1/4" HPT Threads. 1970 pumps are sealed and completely different the 1968 and 1969. The factory fuel line from the tank to pump  and from pump to carb were always 5/16" If you want exact fit replacement fuel lines, buy them from Fine Lines in Ohio...period, do not buy from In-Line tubes, worst tube seller ever and Customer Service is horrible...nothing is their fault....there is a reason they are cheaper then everyone else, don't be fooled. Cameron has provided kit information, I have bought many kits from Antique Auto Parts Cellar/Then and Now and their kits are also friendly with Ethanol Fuels.

Parts book shows the same pump for 69 and 70 with electric wipers (WEW), except for the "WDT" designation in 1970.  What is "DT"?

Think DT-Dual Throat aka 2 barrel carb.