351M Heads vs 351C heads - Ford Forums

LCfromLC · 05-03-2005, 12:07

I brought a pair of American 2V 351C heads to have 4v valves put in them. I got back 2V 351M heads with the 4V valves in them. The machine shop says the 2 heads are identical except for the water jacket. Am I being taken or can I use them to complete my engine.

mach1mike · 05-03-2005, 12:47

I'm not sure & stand to be corrected but I seem to remember the 351m head had a larger chamber size something like 2cc more than a 351c 2V.
HTH
Mike.

grey_esp · 05-03-2005, 16:56

Id be telling them I want my own heads back, regradless.

xyfmtjoe · 05-03-2005, 20:10

Mate if there the later "M" head the water jacket difference in in the exhaust ports that choke them down to a smaller X section than a windsor or cheb head!

Take them back and either compare inside the exh port around the valve guide to your original heads and if there is any diff ie;new heads smaller demand your old heads back!!

xdclevo · 05-03-2005, 20:23

I thought the tall block heads had the nasty hump in the exhaust port. Unless they were agreed to be exchange heads, get the old ones back.

jock · 05-03-2005, 21:36

Get your old heads back - they had no right swapping heads without your permission.

No machine shop/engine builder I have ever dealt with would have done that without ringing me and telling/asking whether they could swap heads or not.

If they were damaged, same deal - they should have rung you. One would have to conclude that something isn't right there!

Get your heads back and find another machine shop.

Cheers Jock

paull · 05-05-2005, 05:32

Many years ago I got the all of the machining done and got what I thought were all my own bits back. Engine assembled and trying to put it back into the car. Stuffed around for hours until we pulled it out again and realised the tossers had given a manual crank (my one was an auto) and it was the spigot bearing not allowing the torque converter to go in. Not happy Jan.

Get your own heads back, they're yours!