Do GT40Ps off Explorer have EGR holes in heads?

Fox Hound · 10-15-2002, 04:22 PM

I need to be smog legal here in CA and was looking into getting some GT40Ps. My question is do the ones off the Explorers have holes for the EGR pre-drilled and would be a direct bolt on to my car?

Joe50 · 10-15-2002, 05:02 PM

Chevyguy · 10-16-2002, 01:37 PM

If I have paid attention correctly, the GT-40P heads may have EGR passages, it's the Stock Explorer Cobra manifold that does not have the internal EGR passages, and would have to be fed an external exhaust source like the Explorer does.

The GT-40P are not drilled for the thermactor ports though( right??)

Fox Hound · 10-16-2002, 07:09 PM

Quote:

The GT-40P are not drilled for the thermactor ports though( right??)

Duuuhhhh..... what and where are thermactor ports????

Chevyguy · 10-17-2002, 04:12 PM

Those are the air tubes attached to the smog pump that screw into the back of the heads and inject air into the exhaust. Ford calls this the Thermactor system. Without this system you will get higher HC readings in general as the air is supposed to allow unburned HC in the exhaust to get burned up before hitting the cats.

A really well tuned motor won't really need this, heck I have heard of someone with a GMC truck who had a chip burned etc and ran emmissions numbers way better than stock without cats or a smog pump.

richd · 10-17-2002, 04:19 PM

I thought the thermactor feed on the heads was only for cold start emissions. Once the engine is warm, the smog pumps air to the cats.

Or am I wrong?

Coupe Devil · 10-17-2002, 10:01 PM

Ok. I am looking to pick up a set of GT 40 heads.. Are all V8 Explorer's Gt40's?? If so or not what year model do I need to look for to get these. I would like ot just buy the junkyard brand for now.

Thanks
Bradley

Fox Hound · 10-18-2002, 11:12 AM

I've read somewhere that only the early '97 Explorers came with GT40 heads. After that, then all came with the Ps. You might want to check the casting for marking to be sure. The GT40P will have "GT40P" stamped on it. I think I will go for the Ps due to better exhaust ports.

Coupe Devil · 10-19-2002, 01:44 AM

So its safe to assume that the P heads have P stamped on them.. I guess i would take which ever I could find... What wil lthe ydo as far as matching up to my headers? I have Headman Longtubes now with no special bolt hole poattern on the exhaust flange.

Thanks
Bradley

10-15-2002, 04:22 PM	#1
Fox Hound Registered Member Join Date: Nov 2001 Location: Bay Area, CA Posts: 58	Do GT40Ps off Explorer have EGR holes in heads? I need to be smog legal here in CA and was looking into getting some GT40Ps. My question is do the ones off the Explorers have holes for the EGR pre-drilled and would be a direct bolt on to my car?

10-15-2002, 05:02 PM	#2
Joe50 Registered Member Join Date: Jan 2000 Location: Newport News, VA Posts: 78	yes __________________ "Drive it like you stole it!" '94 Vibrant Red GT

10-16-2002, 01:37 PM	#3
Chevyguy Backyard Mechanic/Chemist Join Date: Feb 2001 Location: Acton MA USA Posts: 435	If I have paid attention correctly, the GT-40P heads may have EGR passages, it's the Stock Explorer Cobra manifold that does not have the internal EGR passages, and would have to be fed an external exhaust source like the Explorer does. The GT-40P are not drilled for the thermactor ports though( right??) __________________ 2001 Crown Vic Maurader Airbox/MAF, DR chip Edel IAS shocks Single exhaust :wtf: 93 P-71 Vic interceptor Backup car now 90 5.0 LX Notch SOLD 74 Chevy Laguna type S-3 454 under construction Currently apart undergoing bodywork.

10-17-2002, 04:12 PM	#5
Chevyguy Backyard Mechanic/Chemist Join Date: Feb 2001 Location: Acton MA USA Posts: 435	Those are the air tubes attached to the smog pump that screw into the back of the heads and inject air into the exhaust. Ford calls this the Thermactor system. Without this system you will get higher HC readings in general as the air is supposed to allow unburned HC in the exhaust to get burned up before hitting the cats. A really well tuned motor won't really need this, heck I have heard of someone with a GMC truck who had a chip burned etc and ran emmissions numbers way better than stock without cats or a smog pump. __________________ 2001 Crown Vic Maurader Airbox/MAF, DR chip Edel IAS shocks Single exhaust :wtf: 93 P-71 Vic interceptor Backup car now 90 5.0 LX Notch SOLD 74 Chevy Laguna type S-3 454 under construction Currently apart undergoing bodywork.

10-17-2002, 10:01 PM	#7
Coupe Devil Moderator Join Date: Mar 2001 Location: Myrtle Beach SC Posts: 1,643	Ok. I am looking to pick up a set of GT 40 heads.. Are all V8 Explorer's Gt40's?? If so or not what year model do I need to look for to get these. I would like ot just buy the junkyard brand for now. Thanks Bradley __________________ 1990 GT, 347, TFS TW Heads, TFS Cam, TFS Track heat, Twin turbos, FMIC, T5. Built Ford Tough Moderator

10-17-2002, 04:19 PM	#6
richd Registered Member Join Date: Jul 2001 Location: Edison, NJ, USA Posts: 125	I thought the thermactor feed on the heads was only for cold start emissions. Once the engine is warm, the smog pumps air to the cats. Or am I wrong?

10-18-2002, 11:12 AM	#8
Fox Hound Registered Member Join Date: Nov 2001 Location: Bay Area, CA Posts: 58	I've read somewhere that only the early '97 Explorers came with GT40 heads. After that, then all came with the Ps. You might want to check the casting for marking to be sure. The GT40P will have "GT40P" stamped on it. I think I will go for the Ps due to better exhaust ports.

10-19-2002, 01:44 AM	#9
Coupe Devil Moderator Join Date: Mar 2001 Location: Myrtle Beach SC Posts: 1,643	So its safe to assume that the P heads have P stamped on them.. I guess i would take which ever I could find... What wil lthe ydo as far as matching up to my headers? I have Headman Longtubes now with no special bolt hole poattern on the exhaust flange. Thanks Bradley __________________ 1990 GT, 347, TFS TW Heads, TFS Cam, TFS Track heat, Twin turbos, FMIC, T5. Built Ford Tough Moderator

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