The a after gt40 was supposed to be an s. Ok so I was lookin at rebuilt gt40s from promar engines and they said they are from a cobra not explorer but have no thermactor ports so I email him asking if they are really cobra or from an explorer. Below is his reply, is he giving me correct info or is it bum dope?
You would have to measure for assembled height and spring pressure to know
if your beehive springs will swap over. The Cobras with the GT40 had there
Thermactor holes going right into the exhaust not into the head like the E7
heads. Ford did away with the Thermactor ports in the heads to create a
higher flowing port. Neither the GT40 nor the GT40P heads have this
provision. All GT40 and GT40P heads from the factory are pedestal mount. To
retain emissions legality you would have to run your Thermactor ports into
your manifold/headers. You should not run into any piston to valve relief
interference due to valve diameter but you should clay your pistons upon
assembly to check for valve interference due to lift, valve timing, and
duration.
Thank You
Promar Engine
-----Original Message-----
From:
Sent: Friday, August 23, 2013 3:29 PM
To: [email protected]
Subject: Reman gt40 heads
I saw the ad for he remanufactured gt40 on eBay and I have a couple
questions. I have beehive springs on my e7 heads on my 95 mustang gt can I
swap those over to the gt40? Also you state that the gt40s you are selling
are not from an explorer they are genuine cobra heads. But you say they
don't have thermactor ports, the cobras did. Those are early explorer heads
(not p) I have a cam w .512 lift and flat top pistons w valve reliefs think
I will have ptv issues? Are those stud or pedestal mount heads as far as
rockers goes? And w out the thermactor ports how do I retain smog legality?
Sent from my iPhone=
You would have to measure for assembled height and spring pressure to know
if your beehive springs will swap over. The Cobras with the GT40 had there
Thermactor holes going right into the exhaust not into the head like the E7
heads. Ford did away with the Thermactor ports in the heads to create a
higher flowing port. Neither the GT40 nor the GT40P heads have this
provision. All GT40 and GT40P heads from the factory are pedestal mount. To
retain emissions legality you would have to run your Thermactor ports into
your manifold/headers. You should not run into any piston to valve relief
interference due to valve diameter but you should clay your pistons upon
assembly to check for valve interference due to lift, valve timing, and
duration.
Thank You
Promar Engine
-----Original Message-----
From:
Sent: Friday, August 23, 2013 3:29 PM
To: [email protected]
Subject: Reman gt40 heads
I saw the ad for he remanufactured gt40 on eBay and I have a couple
questions. I have beehive springs on my e7 heads on my 95 mustang gt can I
swap those over to the gt40? Also you state that the gt40s you are selling
are not from an explorer they are genuine cobra heads. But you say they
don't have thermactor ports, the cobras did. Those are early explorer heads
(not p) I have a cam w .512 lift and flat top pistons w valve reliefs think
I will have ptv issues? Are those stud or pedestal mount heads as far as
rockers goes? And w out the thermactor ports how do I retain smog legality?
Sent from my iPhone=