How would you compare those heads withe the stated improvements to a set of GT40 heads?SF, the C6 heads should have the smaller 54 cc chambers. If you can get them cheap, you can do a valvejob and add the bigger valves and clean out the exhausts and add hard seats. The early heads, with the bigger 1.94/1.60 valving, can support ~450hp. I'll help with part numbers if you need Is that enough ? LSG
Given the choice, I'd look for some "pre C6" 289 heads before the castings were changed to accommodate Thermactor passages.Flade, the GT40 & GTP heads have the same 1.84 intake valve and 145cc port as the early 351W heads from 1969. If you left both heads alone, and ran them as Ford made them, the GT40 head will be sharply ahead of the C6. But if the C6 heads, ( 1.78 intake & 125cc ports ) are improved with the bigger valves & some porting, they can catch up and easily pass the GT. The smaller chamber is nice on a 289. But prepping the 289 head to this level requires a valvejob, hard exhaust seats, some grinding, and sixteen new valves. You could have seven or eight hundred dollars into the heads. If you are looking for quick & dirty, and the revised plug angle of the P heads doesn't hurt you, then the P heads are fine.
Anyone who is doing the GTP head swap should carefully set the 289 heads aside and then send them to me !
Knowing the header fitment issues that some have had, and because I really like the 54cc small chambers, the e 64-67 289 heads are my favorites. Also, having been employed at the machine shop, I know how the small valve heads can be upgraded, is was a popular choice for many years, before the GTPs were even thought of. LSG
One's cast at Windsor Foundry, the other at Cleveland. One has "internal" Thermactor ports (tube attaches at the end) and the other has "external" (individual tubes attach by each spark plug).What the difference between the c6oe and c6ae?
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There was a pair of 0E and a pair of AE heads for sale but they would have needed everything done to them. They were sitting for years and all rusty, etc. I passed on those.Even without the installation of larger valves, port-matching of the exhaust is a great improvement. I'm curious, though, are you talking about one OE head and one AE head?
Thanks for the info. Win some and loose some. I guess I should have done more homework and been less trusting before buying them.SF, you ARE going to check those heads out carefully before just running them, right ? It looks like some of the exhaust valve tips are chewed up. And why are we seeing rail rockers AND narrow slots in the heads ? Like this set of rockers was an incorrect addition at some point ? You'll want to be certain that the rails on the rockers don't hit the retainers & locks. LSG
Yeah I’d sooner get new rocker arms then drill it out.If you really want to use the rail rockers you could drill out the slots, just check the rocker arms for wear, you may end up needing new ones anyway. I have a set of rocker arms the valve stem tips actually wore a round depression in half of them.