• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-

gt-40's, lower and 1.7's=?

  • Thread starter Thread starter rsw007
  • Start date Start date Nov 7, 2007

rsw007

New Member
Jul 7, 2004
469
1
0
Lexington,SC
Nov 7, 2007
#1
  • Nov 7, 2007
  • #1
i just installed iron gt-40 heads a ported stock lower intake, 1.72 roller rockers and aftermarket ignition box.
what kind of real world gains do you guys think i shoud see in hp and et's?
 

88mouse

New Member
Apr 18, 2007
630
0
0
Mooresville nc
Nov 7, 2007
#2
  • Nov 7, 2007
  • #2
stock intake still? If so that is killing you. Get a intake and cam then you will put down some good #'s.
 

85ragtop

BTW, I like dudes.
10 Year Member
Nov 29, 1999
823
475
123
NC
Nov 7, 2007
#3
  • Nov 7, 2007
  • #3
Moved to talk.
 

Gearbanger 101

Straight Outta Locash
20+ Year Stangneter
Aug 10, 2002
9,457
1,377
234
Ontario, Canada
Nov 7, 2007
#4
  • Nov 7, 2007
  • #4
As it sits, probably another 30hp to the flywheel.
 

bloopbloob

Member
Sep 27, 2006
578
4
16
Alberta
Nov 7, 2007
#5
  • Nov 7, 2007
  • #5
88mouse said:
stock intake still? If so that is killing you. Get a intake and cam then you will put down some good #'s.
Click to expand...

the lower is ported, which is the most restrictive part on the stock intake.

i'm thinking maybe + 25-30 to the wheels
 

rsw007

New Member
Jul 7, 2004
469
1
0
Lexington,SC
Nov 8, 2007
#6
  • Nov 8, 2007
  • #6
yes i massively ported the lower it should flow 180 plus in all runners. and i opened the throttle body opening on the upper to 70mm

im hoping for atleast 11.3's on the 125 shot
 

stykthyn

I want to measure mine. It doesn't look that tall.
15 Year Member
Jul 6, 2006
5,232
2,652
223
gainesville
Nov 8, 2007
#7
  • Nov 8, 2007
  • #7
you ported it or a professional ported it? if you took too much material from the wrong places you may inadvertantly cause reductions in the velocity of the air moving through the runners.
 

ninety15.0

New Member
Mar 10, 2004
1,336
0
0
Nov 8, 2007
#8
  • Nov 8, 2007
  • #8
Were the heads installed as is...with no work done to them. Valve job? Milling?

The combustion chamber on those gt-40 irons is 64.5 cc i believe...which will drop your compression to under 8.5:1. So without any work done to them i would probably say the heads were only worth 20-25 hp and the intake work is probably worth another 10-20...depending on how well you did the port work. total increase of 30-40.

Those Gt-40's really need a lot of exhaust flow to be efficient...think longtubes, O/R X pipe, and some bullets or SLP's.
 

rsw007

New Member
Jul 7, 2004
469
1
0
Lexington,SC
Nov 9, 2007
#9
  • Nov 9, 2007
  • #9
stykthyn said:
you ported it or a professional ported it? if you took too much material from the wrong places you may inadvertantly cause reductions in the velocity of the air moving through the runners.
Click to expand...

thats possible about the velocity but the nitrous will make up for that i hope
 
You must log in or register to reply here.

Similar threads

A
Discussion on mild budget build/ top end
  • Acesario
  • Feb 21, 2026
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 2
Replies
20
Views
709
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Feb 23, 2026
General karthief
C
Dyno day! # guesses?
  • clayton seiders
  • Aug 15, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
15
Views
409
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Aug 16, 2025
Scrapla347
S
Holley High-ram tuning settings
  • spencergt66
  • Apr 1, 2026
  • Digital Self-tuning Forum
  • 2
Replies
28
Views
605
Digital Self-tuning Forum Jun 19, 2026
spencergt66
S
Progress Thread Progress Thread- From6to8's 1994 Cobra Supercharger install
  • from6to8
  • Sep 25, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 20 21 22
Replies
420
Views
9K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- May 6, 2026
from6to8
6
Hey all,I’m putting together a 302 for my 1968 Mustang and wanted to post the combo + some questions to make sure I’m not missing crucial
  • 68_Disgustang
  • Feb 22, 2026
  • 1965 - 1973 Classic Mustangs -General/Talk-
Replies
4
Views
833
1965 - 1973 Classic Mustangs -General/Talk- Jun 20, 2026
gray owl
G
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?