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

Engine New Cam or Different Rockers?

  • Thread starter Thread starter 93CalypsoConvert
  • Start date Start date Jun 12, 2021
  • Tags Tags
    cam swap gt40 heads
Prev
  • 1
  • 2
First Prev 2 of 2

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Jun 18, 2021
#21
  • Jun 18, 2021
  • #21
I got the GT40p heads. They look great and there doesn't seem to be any issues. Added bonus: The heads already have upgraded valve springs. Upon further inspection, I actually have a roller cam/lifters. I find it interesting that the previous owner told me it was flat tappet, considering he, well, owned the thing.
 
Last edited: Jun 18, 2021

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
27,915
10,563
203
polk county florida
Jun 18, 2021
#22
  • Jun 18, 2021
  • #22
So, it's not a roller block?
 

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Jun 18, 2021
#23
  • Jun 18, 2021
  • #23
General karthief said:
So, it's not a roller block?
Click to expand...
Editing that previous response... Turns out it IS roller set up. Nevermind the question I had.
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
27,915
10,563
203
polk county florida
Jun 19, 2021
#24
  • Jun 19, 2021
  • #24
 
Reactions: Wayne Waldrep

Wayne Waldrep

Before I post a pic, do you have one of yours?
20+ Year Stangneter
Apr 14, 2003
1,338
659
143
Cuba, AL
Jun 20, 2021
#25
  • Jun 20, 2021
  • #25
Great thread to read!
Looking forward to hearing your thoughts and results as you do this project.
 

Potomus Pete

I'm still waiting for the fully nude shots
5 Year Member
Mar 7, 2019
3,308
1,223
153
Sarasota Florida
Jun 20, 2021
#26
  • Jun 20, 2021
  • #26
I wish somebody could put the 1.7 rocker kit part numbers that we could use on stud mount stock set up. Some say 1.7 adds decent small hp's, and on Corral they say no extra at all.
 

Wayne Waldrep

Before I post a pic, do you have one of yours?
20+ Year Stangneter
Apr 14, 2003
1,338
659
143
Cuba, AL
Jun 20, 2021
#27
  • Jun 20, 2021
  • #27
This applies to mild hp efforts....
Y'all know how I feel about mild hp gains on a fox body. Whether you have 200 or 325, you are still way below every current performance car and equal to or below half the normal cars....like a Sentra or Accord. Most family sized SUVs can outrun you. So what does that mean? Make your car enjoyable to drive and dependable. Forget hp cause you won't have enough. Put your money in good brakes, nice suspension, nice seats, paint (I need that!), good looking wheels and tires, a good audio system. Make people see your car and say "damn, look at that old Fox body!"
These are just my thoughts. I have nothing against tinkering with engines. I've been doing it for a long time. Just don't concentrate on more hp at the expense of everything else. Again.....what does even 75 more hp honestly get you? An Acura SUV only outruns you by 2 lengths instead of 6?
 
Reactions: Gs1987GT, General karthief, Potomus Pete and 1 other person

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,249
17,934
224
Massachusetts
Jun 20, 2021
#28
  • Jun 20, 2021
  • #28
 
Reactions: Gs1987GT and General karthief

7991LXnSHO

wanna catch the space herp
10 Year Member
Sep 1, 2010
7,387
2,745
194
Kearney, NE
Jun 20, 2021
#29
  • Jun 20, 2021
  • #29
Wayne Waldrep said:
This applies to mild hp efforts....
Y'all know how I feel about mild hp gains on a fox body. Whether you have 200 or 325, you are still way below every current performance car and equal to or below half the normal cars....like a Sentra or Accord. Most family sized SUVs can outrun you. So what does that mean? Make your car enjoyable to drive and dependable. Forget hp cause you won't have enough. Put your money in good brakes, nice suspension, nice seats, paint (I need that!), good looking wheels and tires, a good audio system. Make people see your car and say "damn, look at that old Fox body!"
These are just my thoughts. I have nothing against tinkering with engines. I've been doing it for a long time. Just don't concentrate on more hp at the expense of everything else. Again.....what does even 75 more hp honestly get you? An Acura SUV only outruns you by 2 lengths instead of 6?
Click to expand...
That's just depressing, Morgan Freeman Meme or not.
 
Reactions: Wayne Waldrep

Wayne Waldrep

Before I post a pic, do you have one of yours?
20+ Year Stangneter
Apr 14, 2003
1,338
659
143
Cuba, AL
Jun 20, 2021
#30
  • Jun 20, 2021
  • #30
7991LXnSHO said:
That's just depressing, Morgan Freeman Meme or not.
Click to expand...
Lol... Well, it took me longer than most to give up my all out street racing mentally where I wanted every last bit of hp. But in those days, we could complete. I see my car now as a cool old mustang that used to be fast. I don't need more than that now. I don't want to break it just to win a race. Don't care to risk my life just to beat a loud mouth. So cool cruiser is fine with me now.
Now if the op wants to keep rolling with his mods I'll be happy to read about it!
 
Reactions: Gs1987GT and General karthief

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Jun 27, 2021
#31
  • Jun 27, 2021
  • #31
Update: Got the heads on. Lapped the valves, cleaned mating surfaces, and installed. Took a while but got everything put back together. I screwed up the firing order and thought something major was wrong. whoops. There is a noticeable increase in power and everything is running well. New headers are still on the way... still have the bad stock ones for now. I'll post another update with the part number if I can get those to fit without plug clearance issues.
 
Reactions: Gs1987GT, 90sickfox, Wayne Waldrep and 1 other person

Potomus Pete

I'm still waiting for the fully nude shots
5 Year Member
Mar 7, 2019
3,308
1,223
153
Sarasota Florida
Jun 27, 2021
#32
  • Jun 27, 2021
  • #32
How noticeable. Would you do it again , and how is the power all the way through the throttle. You have to remember the GT 40 heads have become the topic of conversation on many Mustang forums. I would love to do it, but of coarse I have read so much that aluminum aftermarket is the way to go.
 

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Jun 27, 2021
#33
  • Jun 27, 2021
  • #33
Potomus Pete said:
How noticeable. Would you do it again , and how is the power all the way through the throttle. You have to remember the GT 40 heads have become the topic of conversation on many Mustang forums. I would love to do it, but of coarse I have read so much that aluminum aftermarket is the way to go.
Click to expand...
I don't know how to describe it very well, but its enough of a difference to warrant a "holy crap" the first few times I dipped into it. You don't have to push the throttle near as hard to get the same result as before. Difference is present in the whole rpm range, but I think upper end is still choked from exhaust... I'll let you know once my headers get here (and if they fit, of course). I would do it again. I considered aluminum too, but as far as cheap power goes, I think 40s are the way to go. Total cost of the project was about $500.
 
Reactions: Gs1987GT, 7991LXnSHO and Potomus Pete
M

Monkeybutt2000

Mustang Master
Aug 11, 2019
1,387
849
133
Lafayette,IN
Jun 28, 2021
#34
  • Jun 28, 2021
  • #34
I hope you went long tubes because there's really no difference in shorty headers. There's nothing wrong with the gt40 setup,I went 12.80's with the stuff. And as far as an Acura suv outrunning your Mustang,unless you're a terrible driver it's not gonna happen. Looked it up,the newest one runs a 14.2, that was the exact time I ran on my very first pass in my old 87' LX. Just sayin'....
 
Reactions: Gs1987GT and General karthief

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
27,915
10,563
203
polk county florida
Jun 28, 2021
#35
  • Jun 28, 2021
  • #35
Long tubes with gt40p heads will pose a problem with a couple spark plugs, shorty headers work better and I think there is still some made to fit the P's. You really will not lose much, just a little bottom end torque.
I should say 'may' cause issues, I had that setup and was looking for ways around the burnt plug boots when things went south (that's not racist to say yet is it?) with that engine.
 
Last edited: Jun 28, 2021

Potomus Pete

I'm still waiting for the fully nude shots
5 Year Member
Mar 7, 2019
3,308
1,223
153
Sarasota Florida
Jun 28, 2021
#36
  • Jun 28, 2021
  • #36
He better read up because there are issues even with shorties. Certain brands don't work with the GT's. I have read a lot about GT's because I want some. They make sense for cost , and weekend cruisers. I like the way you can use standard rockers. Plus I like iron on iron to save on major head gasket issues.
 

General karthief

wonder how much it would cost to ship you a pair
20+ Year Stangneter
Aug 25, 2016
27,915
10,563
203
polk county florida
Jun 28, 2021
#37
  • Jun 28, 2021
  • #37
Potomus Pete said:
He better read up because there are issues even with shorties. Certain brands don't work with the GT's. I have read a lot about GT's because I want some. They make sense for cost , and weekend cruisers. I like the way you can use standard rockers. Plus I like iron on iron to save on major head gasket issues.
Click to expand...
It's not the GT40 3 bar heads, the issue is with the P's 4 bar heads spark plug angle.
aluminum heads do not have head gasket issues, they have installer issues.
 
Reactions: 93CalypsoConvert

Potomus Pete

I'm still waiting for the fully nude shots
5 Year Member
Mar 7, 2019
3,308
1,223
153
Sarasota Florida
Jun 28, 2021
#38
  • Jun 28, 2021
  • #38
And I would be the installer that would have the head gasket issues...I have never done one, and I fear the head gasket. I would think with the GT heads you don't need tall valve covers. Another plus.
 
M

Monkeybutt2000

Mustang Master
Aug 11, 2019
1,387
849
133
Lafayette,IN
Jun 29, 2021
#39
  • Jun 29, 2021
  • #39
Potomus Pete said:
And I would be the installer that would have the head gasket issues...I have never done one, and I fear the head gasket. I would think with the GT heads you don't need tall valve covers. Another plus.
Click to expand...
I run stock covers with the baffle modified for clearance.
 
Reactions: Gs1987GT

93CalypsoConvert

Active Member
Nov 26, 2020
275
91
38
Virginia
Jun 29, 2021
#40
  • Jun 29, 2021
  • #40
Installed the headers. I can confirm the Speedmaster 746-PCE316.1002 will fit GT40p heads without clearance issues. I have 45 degree plug boots, but I think normal ones would fit too. Might touch the header though. The only piece I had to remove to make them fit was the dipstick.

The driver side was a little more crowded, but the plugs were pretty much in the same spots.

I haven't had a chance to see if there is a difference in power yet. Sounds better idling.
 
Reactions: Gs1987GT, General karthief and Potomus Pete
Prev
  • 1
  • 2
First Prev 2 of 2
You must log in or register to reply here.

Similar threads

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
796
Fox 5.0 Mustang Tech May 7, 2026
MadSquirrelTech
9
Engine Donor '00 Mountaineer meet '91 Fox
  • 91firecracker
  • May 11, 2026
  • Fox 5.0 Mustang Tech
  • 2 3
Replies
41
Views
859
Fox 5.0 Mustang Tech May 28, 2026
91firecracker
9
Ford truck engine swap issues
  • keel
  • Jul 7, 2026
  • Other Auto Tech
Replies
17
Views
232
Other Auto Tech Jul 13, 2026
General karthief
R
New heads
  • Robman8028
  • Jul 30, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
6
Views
770
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Jul 31, 2025
gkomo
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
718
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Feb 23, 2026
General karthief
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?