97GT head swap

speedemon · 11-02-2001, 11:47 AM

I just read an artical about swapping 99-01 GT heads onto my 97GT.With the head swap a decent cat free exhaust,pullys,cold air.I could be over 300 horse by spring.I am wondering if with the 11-1 compresion,that will be the result of the head swap.It will allow me to drive the car on pump gas.I live at 4,000' above sea level.I am ready to void the warantee and get my hands dirty.The chevy guy at work is driving me up the wall.He has a stock 396 chevell that will"kick my butt".
I will also be useing SOV ceramic coated headers as it would be senseless to put the stock manifolds back on.[are these a good choice]

------------------
97 Mustang GT.Bone stock.I have owned 6 other Mustangs.Nothing newer than 1971.

[This message has been edited by speedemon (edited 11-02-2001).]

91LX2Bfast · 11-02-2001, 12:46 PM

Get a light port and polish, and a 3-5 angle valve job if you are shooting for 300HP. YOu'll probably need some long tube headers too. I think 300HP is possible with the stock PI intake, but you might need a Bullitt intake also.
11:1 should be fine with 93-94 octane. You should have a good dyno tune performed though. 11:1 will be a bit much though if you plan any forced induction. You could always have the heads worked to drop the CR if you plan FI in the long term.

DOMIN8R97 · 11-02-2001, 02:45 PM

I don't think you will have any problems running pump gas because I read in MM&FF that the 99-00 GT heads produce 9:1 compression on a 96-98 2V and the 01's run 9.4:1compression which isn't that high. I'm also considering this mod on my '97 GT but with an extrude honed FRPP (Bullitt) Intake kit and instead of the stock PI heads I want to get ported Stage 2 heads from Excessive Motorsports with Sean Hyland Motorsport cams. This is a good setup if you want to add a blower or nitrous.

------------------
Red '97 Mustang GT
Auto
Bone Stock!
(Except for silencer)

91LX2Bfast · 11-02-2001, 02:57 PM

9:1 IS the CR on the 99-00GT's and 9.4:1 is on the '01s.
CR is around 11:1 on 96-98's w/ the swap because they have different pistons.

SD Wheeler · 11-03-2001, 01:26 AM

So just how many of you have actually done this swap and measured the compression ratio?????? Didn't think so.

Here's the lowdown (regardless of what MM&FF says): The '96-'98 engines have flat top pistons with no reliefs; with the '99 & up heads (even the '01 heads) compression is 10.3 to 10.6 depending on individual block/piston assemblies. I have measured the piston depths on 8 different shortblocks and they all vary from .012" to .004" down the bore with the piston at TDC. The '99 & up heads are stated to be 43cc's. I have cc'd 10 different sets and they range from 43.4 to 46cc's.

You're going to be fine even at your altitude. Do the swap and go on with life. Simple.

------------------
SD Wheeler

M/M #30 '98 GT
Strictly Performance
MV Performance

"The Game"

speedemon · 11-03-2001, 04:48 PM

This swap is definatly going to happen.It looks like I will order the heads and cams new from Ford.Also the SVT Headers.I know other people have done this swap and it looks a bit tricky.I would love to hear from people that have done this.I would also like info on timeing the cams with the crank.Also should I burn a new chip when all is said and done?
Thanks....Gary

------------------
97 Mustang GT.Bone stock.I have owned 6 other Mustangs.Nothing newer than 1971.

1BadAzzGT · 11-04-2001, 06:56 PM

You should be just fine with new heads. Everyone says that the compression ratio goes up so much but remember that the newer modular Cobra's are around 9.8:1 and there are tons of people running tons of boost, NOS, etc and doing just fine. It's all in the tune!

Look at my mod list... I have 5.4/99PI heads and the car runs great!

------------------
T. Teal
Founder, Tealnet.com

Check out my 1998 Mustang GT

Mods: Vortech "S" trim supercharger, 5.4 heads (p&p), cams (reground), 99 intake, ATI 3 core intercooler, AFM Powerpipe, Steeda Lower Control Arms, Steeda Upper Control Arms, Steeda Moly Subframes w/cross-brace, 42 lb injectors, no FMU, Walbro 255 in-tank fuel pump, Walbro 255 in-line fuel pump, Ae

11-02-2001, 11:47 AM	#1
speedemon Registered Member Join Date: Sep 2001 Location: Calgary,Alberta,Canada Posts: 14	97GT head swap I just read an artical about swapping 99-01 GT heads onto my 97GT.With the head swap a decent cat free exhaust,pullys,cold air.I could be over 300 horse by spring.I am wondering if with the 11-1 compresion,that will be the result of the head swap.It will allow me to drive the car on pump gas.I live at 4,000' above sea level.I am ready to void the warantee and get my hands dirty.The chevy guy at work is driving me up the wall.He has a stock 396 chevell that will"kick my butt". I will also be useing SOV ceramic coated headers as it would be senseless to put the stock manifolds back on.[are these a good choice] ------------------ 97 Mustang GT.Bone stock.I have owned 6 other Mustangs.Nothing newer than 1971. [This message has been edited by speedemon (edited 11-02-2001).]

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11-02-2001, 12:46 PM	#2
91LX2Bfast Registered Member Join Date: Dec 1999 Location: Warrington, PA Posts: 694	Get a light port and polish, and a 3-5 angle valve job if you are shooting for 300HP. YOu'll probably need some long tube headers too. I think 300HP is possible with the stock PI intake, but you might need a Bullitt intake also. 11:1 should be fine with 93-94 octane. You should have a good dyno tune performed though. 11:1 will be a bit much though if you plan any forced induction. You could always have the heads worked to drop the CR if you plan FI in the long term.

11-02-2001, 02:45 PM	#3
DOMIN8R97 Registered Member Join Date: Aug 2001 Location: Arlington Heights, Illinois Posts: 29	I don't think you will have any problems running pump gas because I read in MM&FF that the 99-00 GT heads produce 9:1 compression on a 96-98 2V and the 01's run 9.4:1compression which isn't that high. I'm also considering this mod on my '97 GT but with an extrude honed FRPP (Bullitt) Intake kit and instead of the stock PI heads I want to get ported Stage 2 heads from Excessive Motorsports with Sean Hyland Motorsport cams. This is a good setup if you want to add a blower or nitrous. ------------------ Red '97 Mustang GT Auto Bone Stock! (Except for silencer)

11-02-2001, 02:57 PM	#4
91LX2Bfast Registered Member Join Date: Dec 1999 Location: Warrington, PA Posts: 694	9:1 IS the CR on the 99-00GT's and 9.4:1 is on the '01s. CR is around 11:1 on 96-98's w/ the swap because they have different pistons.

11-03-2001, 01:26 AM	#5
SD Wheeler "The Game" Join Date: Apr 1999 Location: Baytown, Texas USA Posts: 955	So just how many of you have actually done this swap and measured the compression ratio?????? Didn't think so. Here's the lowdown (regardless of what MM&FF says): The '96-'98 engines have flat top pistons with no reliefs; with the '99 & up heads (even the '01 heads) compression is 10.3 to 10.6 depending on individual block/piston assemblies. I have measured the piston depths on 8 different shortblocks and they all vary from .012" to .004" down the bore with the piston at TDC. The '99 & up heads are stated to be 43cc's. I have cc'd 10 different sets and they range from 43.4 to 46cc's. You're going to be fine even at your altitude. Do the swap and go on with life. Simple. ------------------ SD Wheeler M/M #30 '98 GT Strictly Performance MV Performance "The Game"

11-03-2001, 04:48 PM	#6
speedemon Registered Member Join Date: Sep 2001 Location: Calgary,Alberta,Canada Posts: 14	This swap is definatly going to happen.It looks like I will order the heads and cams new from Ford.Also the SVT Headers.I know other people have done this swap and it looks a bit tricky.I would love to hear from people that have done this.I would also like info on timeing the cams with the crank.Also should I burn a new chip when all is said and done? Thanks....Gary ------------------ 97 Mustang GT.Bone stock.I have owned 6 other Mustangs.Nothing newer than 1971.

11-04-2001, 06:56 PM	#7
1BadAzzGT Registered Member Join Date: Oct 1999 Location: Pasadena,, Maryland, USA Posts: 35	You should be just fine with new heads. Everyone says that the compression ratio goes up so much but remember that the newer modular Cobra's are around 9.8:1 and there are tons of people running tons of boost, NOS, etc and doing just fine. It's all in the tune! Look at my mod list... I have 5.4/99PI heads and the car runs great! ------------------ T. Teal Founder, Tealnet.com Check out my 1998 Mustang GT *Mods:* Vortech "S" trim supercharger, 5.4 heads (p&p), cams (reground), 99 intake, ATI 3 core intercooler, AFM Powerpipe, Steeda Lower Control Arms, Steeda Upper Control Arms, Steeda Moly Subframes w/cross-brace, 42 lb injectors, no FMU, Walbro 255 in-tank fuel pump, Walbro 255 in-line fuel pump, Ae