• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

Gt40 Heads On Stock 1986 Mustang

  • Thread starter Thread starter tacomatrx450f
  • Start date Start date Apr 30, 2013

tacomatrx450f

Member
May 24, 2009
33
0
7
Apr 30, 2013
#1
  • Apr 30, 2013
  • #1
Hey Guys, i searched, and searched, but before i pull out my wallet, just wanted to make sure.
I am having a pair of GT40P heads reconditioned, 3 angle job, and resurfaced, and i wanted to know if i could use my stock 86 push rods, and rockers. I will be using my stock cam, but could i throw on the 86 stock valve springs?, or would i need to buy the TFS-2500100 spring kick from trick flow? my BBK headers look like they will clear the spark plugs, but is there anything else that I should have performed while the work is being done to the heads? thanks again guys
 

a91what

SendMeUrDataLog
10 Year Member
Apr 6, 2011
10,739
6,721
214
Hillsborough county
Apr 30, 2013
#2
  • Apr 30, 2013
  • #2
86.... Does your engine have flat top pistons in it?. If so a ptv issue probably will occur. I would use new springs.
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,260
17,945
224
Massachusetts
May 1, 2013
#3
  • May 1, 2013
  • #3
Use new springs, not your 27-year old springs.

Like mentioned before, is using original 86 flat-top pistons, you may have PTV issues. You definitely want to clay the head when you install. The Intake valve is larger on the 40P, so you may have issues and need to replace the pistons, or cut notches in them
 
You must log in or register to reply here.

Similar threads

9
Engine Donor '00 Mountaineer meet '91 Fox
  • 91firecracker
  • May 11, 2026
  • Fox 5.0 Mustang Tech
  • 2 3
Replies
41
Views
920
Fox 5.0 Mustang Tech May 28, 2026
91firecracker
9
Engine Suggestions on an engine rebuild. Stock cam/GT40Ps or aftermarket on both for a fun weekend driver?
  • MadSquirrelTech
  • Apr 28, 2026
  • Fox 5.0 Mustang Tech
  • 2
Replies
23
Views
838
Fox 5.0 Mustang Tech May 7, 2026
MadSquirrelTech
T
Resolved No run or idle
  • Thebluefox1
  • Oct 10, 2025
  • Fox 5.0 Mustang Tech
Replies
14
Views
528
Fox 5.0 Mustang Tech Nov 25, 2025
DadLife0724
M
Engine Unexplainable Exhaust Pop and Gurgle
  • Mrnissen122
  • Feb 14, 2026
  • Fox 5.0 Mustang Tech
Replies
12
Views
577
Fox 5.0 Mustang Tech Feb 18, 2026
Noobz347
Engine Pushrod Length?
  • foxbodyclark
  • Jan 25, 2025
  • Fox 5.0 Mustang Tech
Replies
1
Views
360
Fox 5.0 Mustang Tech Jan 25, 2025
limp
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech
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?