Engine Ford Explorer GT40 intake and heads

R

RJ'SDAD

Member

Nov 10, 2019

7

3

13

Hutto, Texas

May 12, 2020

#1

• May 12, 2020

• #1

I know that I can change out the intake and heads on my 89 Mustang, but my question is can I also run a E303 cam with the GT40 heads? Thanks in advance.

 

KRUISR

10 Year Member

Apr 16, 2015

1,816

925

143

May 12, 2020

#2

• May 12, 2020

• #2

Many have. I actually purchased a used motor a year ago that was that exact combination (actually it was an E303 with 1.7 roller rockers as well). I changed the cam for something else but it should be no issue. As always with any cam change, piston to valve clearance should be checked.

 

R

RJ'SDAD

Member

Nov 10, 2019

7

3

13

Hutto, Texas

May 12, 2020

#3

• May 12, 2020

• #3

I guess that is what I'm trying to avoid. I was hoping that it's been done and nothing to worry about. Thanks for the reply! I guess with any build checking tolerance should be a normal practice.

 

D

Deleted member 215073

May 13, 2020

#4

• May 13, 2020

• #4

You will need to change the valve springs on the Explorer head before you install them on a Mustang.

 

R

RJ'SDAD

Member

Nov 10, 2019

7

3

13

Hutto, Texas

May 13, 2020

#5

• May 13, 2020

• #5

What if I decide to use the cam that came in the Mustang. Just a head and intake install... I'm fine then correct?

 

D

Deleted member 215073

May 13, 2020

#6

• May 13, 2020

• #6

No, you still need to change the valve springs regardless of cam unless you plan to run the Explorer cam.

 

2000xp8

SN Certified Technician

Aug 8, 2003

8,027

1,618

194

NJ

May 15, 2020

#7

• May 15, 2020

• #7

The gt40 iron head springs will most likely put up with a stock cam.
With that said, gt40 iron stuff is barely worth the effort with a cam, without it the value drops even further.
Me personally, i'm not taking the heads off my car to rake in 250rwhp total.

 

L

lemosley1973

Doing something with a heavy tranny now

Feb 18, 2019

222

66

38

Clover, SC

May 16, 2020

#8

• May 16, 2020

• #8

JMGlasgow said:

No, you still need to change the valve springs regardless of cam unless you plan to run the Explorer cam.

Click to expand...

Why is that? I'm looking at doing this swap eventually, so good to know what all needs to be done.

 

2000xp8

SN Certified Technician

Aug 8, 2003

8,027

1,618

194

NJ

May 16, 2020

#9

• May 16, 2020

• #9

The explorer cam is a mild truck cam.
You go too far from that and you will have valve float.
Basically the springs can't keep up with the cam and could leave a valve very briefly in the wrong position.
With the stock mustang cam i'd guess it could be ok, but at the same time as i said above, why go through the trouble of swapping heads and leaving the stock cam.
With an aftermarket cam, floating the valves eventually is almost certain.

 

Reactions: lemosley1973

2000xp8

SN Certified Technician

Aug 8, 2003

8,027

1,618

194

NJ

May 16, 2020

#10

• May 16, 2020

• #10

Your best bet with these heads is to get the right set of springs (the info is around here somewhere) and take them to the machine shop for a valve job. They will install the springs, shim as necessary and get the seat pressure right.
A good valve job in worth quite a bit of power for the $200 it costs.
You could do the springs yourself, but the reality is that you will be putting heads on your car that had over 100,000 miles on them. No explorer was low mileage.

 

M

mrspeed

15 Year Member

Mar 2, 2012

27

13

13

North Carolina

May 16, 2020

#11

• May 16, 2020

• #11

The GT40p factory valve springs can't take anything over .450 lift. Visit https://www.alexsparts.com/categories/FORD,-SMALL-BLOCK-302-HO-&-GT40P,-GT40/ for an affordable valve spring kit for these heads.

 

M

mrspeed

15 Year Member

Mar 2, 2012

27

13

13

North Carolina

May 16, 2020

#12

• May 16, 2020

• #12

https://www.alexsparts.com/sb-ford-gt40p-drop-in-valve-spring-kit-hyd-roller-530-lift-vsk7f49-q5/ should do it.