hey adder
12-21-2006, 10:58 PM
#11
Banned
Join Date: Dec 2005
Location: Lil' Rhody
Posts: 22,376
RE: hey adder
Alright mattdel.. i just did a TON of searching here on the forum to try to find an old post of mine... looks like i was off a bit on the chamber size for the explorer heads.. its 65.5cc not 66-67cc
https://mustangforums.com/fb.asp?m=2182155
https://mustangforums.com/fb.asp?m=2182155
ORIGINAL: AdderMk2
http://www.stangpro.com/html/article...les/gt40p1.htm
"The GT-40P replaced the standard GT-40 on the V8 Explorers and Mountaineers in early 1997. Yes, that's right, the Explorers got Cobra heads (although the Cobra's heads were milled to bring it's larger combustion chamber down to the size of the E7TE to keep compression up). "
"Smaller 59cc (up to 61cc based on factory tolerances) combustion chambers (65.5cc in unmilled GT-40 w/ FRPP valves). Great for NA cars as this equates to a raised compression ratio when switching from E7TE castings. Should get you close to 9.5:1 (w/ stock pistons). Cut 0.030" off the bottom and you're close to 10:1 (w/ stock pistons)."
http://www.stangpro.com/html/article...les/gt40p1.htm
"The GT-40P replaced the standard GT-40 on the V8 Explorers and Mountaineers in early 1997. Yes, that's right, the Explorers got Cobra heads (although the Cobra's heads were milled to bring it's larger combustion chamber down to the size of the E7TE to keep compression up). "
"Smaller 59cc (up to 61cc based on factory tolerances) combustion chambers (65.5cc in unmilled GT-40 w/ FRPP valves). Great for NA cars as this equates to a raised compression ratio when switching from E7TE castings. Should get you close to 9.5:1 (w/ stock pistons). Cut 0.030" off the bottom and you're close to 10:1 (w/ stock pistons)."
12-21-2006, 11:01 PM
#12
Banned
Join Date: Dec 2005
Location: Lil' Rhody
Posts: 22,376
RE: hey adder
AND this one too
https://mustangforums.com/fb.asp?m=2181932
[align=center] [/align]
https://mustangforums.com/fb.asp?m=2181932
ORIGINAL: AdderMk2
Thanks for helping me out on this one onyx... its always nice to have the correct information.
Factory tolerances on Ford GT-40P heads provide a 59cc-61cc combustion chamber, where a stock "unmilled" GT-40 would be closer to 64-65.5cc.
It is also stated on stangpro.com that swapping an unmilled gt-40P onto a stock bottom end 5.0 ho would provide a compression boost from 9:1 to 9.5:1, where you would additionally gain .5 more if you milled them 0.030. raising your total compression to 10:1 on a stock bottom end.
Cobra GT-40 heads were milled to have a smaller combustion chamber than the Explorer GT-40 heads of 96-97.5, but the gt-40P's circa 97.5+ had smaller chambers which would further raise the compression ratio as stated above.
Long story short. Installing AFR165cc heads with 58cc chambers effectivly raises your compression ration to about 9.5-9.6:1
ORIGINAL: OnyxCobra
please check for me, my Service Manual says 64cc, but I'd be interested if another reputable source says otherwise...
please check for me, my Service Manual says 64cc, but I'd be interested if another reputable source says otherwise...
Factory tolerances on Ford GT-40P heads provide a 59cc-61cc combustion chamber, where a stock "unmilled" GT-40 would be closer to 64-65.5cc.
It is also stated on stangpro.com that swapping an unmilled gt-40P onto a stock bottom end 5.0 ho would provide a compression boost from 9:1 to 9.5:1, where you would additionally gain .5 more if you milled them 0.030. raising your total compression to 10:1 on a stock bottom end.
Cobra GT-40 heads were milled to have a smaller combustion chamber than the Explorer GT-40 heads of 96-97.5, but the gt-40P's circa 97.5+ had smaller chambers which would further raise the compression ratio as stated above.
Long story short. Installing AFR165cc heads with 58cc chambers effectivly raises your compression ration to about 9.5-9.6:1
12-22-2006, 12:03 AM
#15
6th Gear Member
Join Date: Jun 2006
Location: Maine
Posts: 5,693
RE: hey adder
ORIGINAL: mattdel
you said last night that 96-97 1/2 explorer heads are the same heads as 94-95 cobra. right? if so... i got an Autozone salvage part quote of $199 a piece for 96 explorer 5.0 heads. good deal?
you said last night that 96-97 1/2 explorer heads are the same heads as 94-95 cobra. right? if so... i got an Autozone salvage part quote of $199 a piece for 96 explorer 5.0 heads. good deal?
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