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

4cyl to 5.0 Conversion Questions

  • Thread starter Thread starter 5ohMustang
  • Start date Start date Oct 11, 2004

5ohMustang

Founding Member
Jul 18, 2001
623
0
0
NJ/Alaska/Currently Afghanistan
Oct 11, 2004
#1
  • Oct 11, 2004
  • #1
Interested in getting more info on this conversion. Mainly, I'd like to know what parts need to be changed for this to work. I searched the threads as I know this has been covered a million times, but was unable to find what I was looking for (wrong search words maybe?). Are there any webpages that go through this conversion in detail? Also, for those that have done the conversion, was it worth it and how much did it end up costing?
Thanks,
Brian
 
V

v8only

Active Member
Jul 3, 2003
2,378
22
49
Oct 11, 2004
#2
  • Oct 11, 2004
  • #2
if you're doing this by collecting indiv parts, forget it unless you plan on going carb'd.

I've helped my friend with this converting over an 89 4 banger notch auto to a v8 5 speed.

I assume you want to convert to make it look "factory" and do this the "right" way without cutting corners.

Really, the only way you should do this is to have a wrecked parts car on hand, and you want the same year, or darned close, as their are slight wiring changes across years that can throw you for a loop.

My buddy had a totaled 89 vert, and he put everything onto the 89 notch.

now, before I go into detail, I must say this is a VERY easy job.........for the mechanically inclined. It is extremly laborious and time consuming, but everything is straight forward.

To do this the proper way:

yank EVERYTHING from the 4 cyl chassis. This is assuming it's an auto and you want a v8 5 speed:

-yank the engine, trans, ecu, ecu harness AND engine bay wiring harness. Dash wiring harness and body wiring harness stays. yank the pedal assembly, center console, ALL fuel lines back to the tank, and the rear end. yank the front rotors AND spindles off.

Notches started life as a v8, and were adapted at the factory for a 4 banger. that's the good news. the only thing you'll need to do for that k member to hold the v8 is to remove the 4 cylinder engine mount brackets. 2 bolts, and they're off, drop in your 5.0 and trans all in one pop. The v8 car has the trans x member a little further back, so use the v8 trans x member. Brackets are already present in car.

Great, you've got your engine/trans bolted in. Before this, I should have mentioned to swap in the quick ratio steering rack from the v8 car. Do this while the engine is out. this is simple. Swap in all the fuel lines from the v8 car from the engine back to the tank. swap in the v8 engine bay wiring harness, and ecu and ecu harness. Swap in the v8 spindles and rotors, then swap in your 8.8 rear. I forget, but you may have to swap in the v8 brake lines.

swap in the clutch pedal assembly, clutch cable, and any other odds and ends.

this is why you need a v8 parts car, you're essentially trading EVERY mechanical part.

forgot to mention, swap in the v8 springs too.

If you want to cut corners, you can skip most of the wiring by going carb'd, leave the 4 banger brakes on, leave the 7.5 in, and leave the 4 banger springs on. You'll have quite a sloppy ride, but you can shortcut this.
 
8

87'GTstang

New Member
Feb 16, 2004
1,025
0
0
Oct 11, 2004
#3
  • Oct 11, 2004
  • #3
v8only said:
if you're doing this by collecting indiv parts, forget it unless you plan on going carb'd.

I've helped my friend with this converting over an 89 4 banger notch auto to a v8 5 speed.

I assume you want to convert to make it look "factory" and do this the "right" way without cutting corners.

Really, the only way you should do this is to have a wrecked parts car on hand, and you want the same year, or darned close, as their are slight wiring changes across years that can throw you for a loop.

My buddy had a totaled 89 vert, and he put everything onto the 89 notch.

now, before I go into detail, I must say this is a VERY easy job.........for the mechanically inclined. It is extremly laborious and time consuming, but everything is straight forward.

To do this the proper way:

yank EVERYTHING from the 4 cyl chassis. This is assuming it's an auto and you want a v8 5 speed:

-yank the engine, trans, ecu, ecu harness AND engine bay wiring harness. Dash wiring harness and body wiring harness stays. yank the pedal assembly, center console, ALL fuel lines back to the tank, and the rear end. yank the front rotors AND spindles off.

Notches started life as a v8, and were adapted at the factory for a 4 banger. that's the good news. the only thing you'll need to do for that k member to hold the v8 is to remove the 4 cylinder engine mount brackets. 2 bolts, and they're off, drop in your 5.0 and trans all in one pop. The v8 car has the trans x member a little further back, so use the v8 trans x member. Brackets are already present in car.

Great, you've got your engine/trans bolted in. Before this, I should have mentioned to swap in the quick ratio steering rack from the v8 car. Do this while the engine is out. this is simple. Swap in all the fuel lines from the v8 car from the engine back to the tank. swap in the v8 engine bay wiring harness, and ecu and ecu harness. Swap in the v8 spindles and rotors, then swap in your 8.8 rear. I forget, but you may have to swap in the v8 brake lines.

swap in the clutch pedal assembly, clutch cable, and any other odds and ends.

this is why you need a v8 parts car, you're essentially trading EVERY mechanical part.

forgot to mention, swap in the v8 springs too.

If you want to cut corners, you can skip most of the wiring by going carb'd, leave the 4 banger brakes on, leave the 7.5 in, and leave the 4 banger springs on. You'll have quite a sloppy ride, but you can shortcut this.
Click to expand...

I'de have to say something about that 7.5" rear, the last years of the 5.0, 87' and up mainly (nut 86's as well i suppose) had some serious power - it will blow the rear up with time and decent power levels.
 
V

v8only

Active Member
Jul 3, 2003
2,378
22
49
Oct 11, 2004
#4
  • Oct 11, 2004
  • #4
I couldn't agree more, and def think not to shortcut the 8.8, however, consider the 85 mustang gt's got the 7.5, and their power output was nearly identical to the 86-93 cars, and many 85's are still running around with the original 7.5
 

5ohMustang

Founding Member
Jul 18, 2001
623
0
0
NJ/Alaska/Currently Afghanistan
Oct 11, 2004
#5
  • Oct 11, 2004
  • #5
Thanks for the info. The first thing I was planning on taking care of is the 8.8 rear as the car I'm looking at right now has no engine, trans, or rear in it. Since this will be a project car, I don't plan on cutting any corners. My last question for now is, since it's an '89 and all I need to switch around is the engine bay wiring, am I better off going with EFI? It will definately be a race car, I just haven't decided if it's going to be for drag racing or road courses.
Thanks again,
Brian
 

bluevenom867

I will have images of molesting stuffed animals in
Dec 15, 2003
1,704
1
0
St.Petersburg,FL
Oct 11, 2004
#6
  • Oct 11, 2004
  • #6
Carb is fine.Makes more power n/a and is easier to install.Much cheaper too.I've never had any problems with my carbed 351 in my fox (86GT).
 

DarkMesa8

Founding Member
Oct 15, 2002
1,087
0
0
Orlando, FL
Oct 12, 2004
#7
  • Oct 12, 2004
  • #7
When the time comes (the 2.3L dies) I'll be going to a carbed 302. That way I won't be hunting/paying for a wrecked 5.0.

Plus, I already have the motor sitting here ready to go.
 
B

bazzman

New Member
May 10, 2003
11
0
0
ky
Oct 12, 2004
#8
  • Oct 12, 2004
  • #8
well i started my 4cyl. to 5.0 swap back in june of 01' and im not done yet!LOL...granted i have put the project on the back burner a few times during this period...if i had it to do over i would DEFINITELY get a factory 5.0 car to begin with for sure....i mean ive had fun building it up...but its just too much of a head ache sometimes!.....THE BEST way to do it though would be to have a complete wrecked or junked out 5.0 car to swipe the parts from that way you know where everything goes the first time!...i havent had that luxury !....one good thing about the 4cyl mustangs is more than likely the chassis are in good shape meaning the torque boxes are usually not torn up like the V8 cars usually are...and yes everything needs to be changed out!...as an example you will tell yourself something like "i will just keep the small 4cyl brakes on there for now" yeah right!....i dont mean to discourage you but just wanted to let you know my experience!.....i will try to answer some of your questions so just ask away!
 
B

Boss 351

Here sthhhhhhhheeeve take a picthh of my man flowe
Jul 13, 2003
2,433
23
48
Canada
Oct 12, 2004
#9
  • Oct 12, 2004
  • #9
I let it run last summer with the 4cy breaks... never had a problem.

Best best is to find another 5.0 as a donner car though. Unless you want something faster than a stock 5.0. Get a T5, 351W carbed, 8.8rear, Lincoln brakes...
 
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