TR Benj

I need help and Tim Cochran on these heads, when i bought them 5 years ago i was told they were GT's but i dont think they are, I re-sold them and recently got them back. They are new, slant plugs, hardened seats, 2 slashes on the side, definitely Stainless valves and the intakes are 1.840 and the exhausts are 1.531 the only other markings i found are 5D18   MM also there are 3, 1/2 brass plugs in the valley, why the stainless and the brass plugs im wondering also?

they were brand new, so i know they were not re-worked

eric lavine wrote: talked to a Tom at FMR, and he told me they are GT40 marine heads, 69cc chamber and the cast number i found is F3JECA, ant they do only have 2 casting lines on the ends, they are not the p"s

Interesting. Ive never heard of special GT40 "marine" heads- I had assumed them to be the same as automotive GT40 heads that came installed on the Mustang Cobra and Ford Lightning in the early 90's, and the 5.0 Explorer through '96. Those have smaller chambers than the ones youre quoting (~64cc, IIRC) and have 3 bars in the casting, though the 1.84/1.54 valves are consistent. GT40p heads have 4 bars and arent that closely related.

Can anyone with a factory PCM 351w HO (ProBoss or GT40) confirm how many lines are in the casting? Here are what the lines on the P heads look like for reference:

I'm 99.99999% sure mine have 3 bars.