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Engine 302 Build

  • Thread starter Thread starter Tancalhan
  • Start date Start date Sep 28, 2020
T

Tancalhan

Member
Apr 11, 2020
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2
18
Frederic WI
Sep 28, 2020
#1
  • Sep 28, 2020
  • #1
So I’m building a 302 this winter for the 83. I got a good deal on a 99 explorer motor with gt40p heads. The cyl walls are good so they just need to be honed. The heads are in good shape too so I was just planning on doing upgraded springs. I think I’m gonna get a set of forged Foxbody pistons instead of the hypeuretetic pistons. I was looking at cams and I was gonna do the B303 cam, but after researching more I found conflicted results. I’ve heard the stock 5.0 cam is really good, would it be best for me to go stock cam with those heads? Basically a stock motor with gt40p heads. Oh yea it’s gonna be carbureted Because I can’t afford any type of EFI system.
 

7991LXnSHO

wanna catch the space herp
10 Year Member
Sep 1, 2010
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Kearney, NE
Sep 28, 2020
#2
  • Sep 28, 2020
  • #2
The main thing wrong with a carb in a Fox is a hack job of the wiring going from EFI. If you have a carb in the 83, I’d stick with a vac secondary Holley with a quick change spring kit and an electric choke.
The dual snorkel air cleaner and factory CAI looks good and works.
Is the cam a stock 5.0 HO or the Explorer cam? As you are in there, you might as well upgrade the springs and cam.
 
T

Tancalhan

Member
Apr 11, 2020
30
2
18
Frederic WI
Sep 28, 2020
#3
  • Sep 28, 2020
  • #3
It’s an 83 so it was factory carb. In my post I was asking if I should run the B303 cam, or a stock cam. I’m not doing explorer cam cuz It’s not good.
 

7991LXnSHO

wanna catch the space herp
10 Year Member
Sep 1, 2010
7,387
2,745
194
Kearney, NE
Sep 29, 2020
#4
  • Sep 29, 2020
  • #4
The important part is matching the new valve springs on the Gt-40P heads to your new cam.
As far as to which cam, the FMS B would be my second choice. The first choice would be to call a cam tech line with all the rest of your car’s parts’ info and intended use/power band, see what off the shelf grind matches the ideal grind best, and is newer tech than the FMS B cam.
 
Last edited: Sep 29, 2020
Reactions: General karthief

2000xp8

SN Certified Technician
Aug 8, 2003
8,015
1,613
194
NJ
Sep 29, 2020
#5
  • Sep 29, 2020
  • #5
I wouldn't screw with the shortblock at all (other than the cam) unless you know for a fact it needs a rebuild.
Many times people take an engine that runs just fine and they make it worse.
I certainly wouldn't blow money on pistons for it.
Explorer engines were mid range engines connected to automatic transmissions and most weren't beat on.
Unless you attempt to pump a serious amount of power through it, they will be fine and even then most likely they will outlast the block itself.

For a cam, i'd probably just run an E with some new springs.
May not be the most popular pick, but with p heads, i'm not sure it's all that big of a deal.
 
R

Rcdgl

5 Year Member
Feb 19, 2018
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63
Sep 29, 2020
#6
  • Sep 29, 2020
  • #6
Check the piston to valve clearance with any setup your try. I would suggest upgrading the valve springs. Note that there are some involved items here. There are rotators on the exhausts, so you would be best with a kit from Comp or similar that comes with the springs, specific retainers, etc. Make sure to verify proper pushrod length. I suggest a Comp XE 274 HR. Also suggest a Holley 80457 carb.
 
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