84 v6 mustang v8 swap

[kingjay05]

I have an 84 v6 lx mustang that I want to convert into a v8. I have a complete 94 gt donor that I’m going to be using for the swap. My 84 is a throttle body injected engine so do I need to still swap the fuel system? I know that I’d need to swap the suspension, breaks, and K member so my plan is to unbolt everything from the front end and lift the car over the engine. this would be my first time doing the swap so what would possibly be the best starting point?

thanks
Jay

[Walking-Tall]

Fuel system changes, yes, (you omitted the important detail of...) if you're planning on using a carburetor in your 1984, which needs 4-6psi as opposed to the ~40psi of fuel pressure your fuel pump/s provide. If you're lucky, and again if you're going to use a carburetor, there's an in-tank pump and an external pump... the external being a high pressure pump, the in-tank pump being a low pressure "lift pump". See my build thread for ideas/pointers if you're winding back the clock to carburetor simplicity. If you're going to keep all of the '94's EFI, ignore the above.

You do not need to change the k-member out of a 1984 3.8L V6 car to put in a small block Ford V8. That was only an issue with earlier cars if replacing a 3.3L 200 cubic inch straight 6 engine with a 302 V8. Yank out the engine and transmission like normal.

[4eyedblind]

You should take EVERYTHING out of the 94 and shove it in the 84. The K memeber is wider on the 87+ cars, improving geometry, you'll get disc rears (even if the axles are a little long), etc. You can use the EFI in tank pump to feed the standard port fuel injection, as it is the same pump as the V8 got. I did this last year on an 86 and I used a rusted 88GT as a donor car. Every clip, wire, hose I needed.

[kingjay05]

Thank you, I’m gonna get started this weekend

[erratic50]

If you are swapping in a V8 with multiport EFI you are going to have wiring to do

Easiest fix is a swap to 86 wiring throughout. If you want MAF do a conversion on the 86 harness

source the 86 O2 sensors, TPS, etc.

relatively cheap upgrades ($250 new) for a lot more RPM range and power and fun is 1.7:1 rockers and a Typhoon EFI intake, reworked 65MM throttle body setup as for a fox, 70 mm MAF, 24 lb injectors, 93 Cobra ECU, shorty headers

North Racecars has the needed brackets and axles for going to a fox width rear axles in 5 lug with SN95 brakes

94-95 spindles in front work well but ream top strut bolt for more negative camber or use camber bolts. Or SVO rotors on 87-93 spindles or even SVO spindles if you don’t mind the rotor snout and bearing type

Either way SN95 balljoints in fresh replacement front control arms. Take the high friction stock style stuff and ****can it. SVO spindles require a MM balljoint adapter

You need V8 springs in front, double check rates of what you have in each car vs factory TRX or GT cars

Eventually front swaybar needs to be from TRX or its too strong. Wait until rear is addressed

rear springs in the 84 will be comparable to 93 cobra.

You will want a fox GT style rear swaybar but only if you add a panhard too and downsize up front

Easier and better IMO to swap to fox style brackets and pulleys. Under drive kit, use crank and alternator. Source a cobra style water pump pulley from Summit

more or less that’s what I would do. Make under hood look period — like it belongs

[kingjay05]

If you are swapping in a V8 with multiport EFI you are going to have wiring to do

Easiest fix is a swap to 86 wiring throughout. If you want MAF do a conversion on the 86 harness

source the 86 O2 sensors, TPS, etc.

relatively cheap upgrades ($250 new) for a lot more RPM range and power and fun is 1.7:1 rockers and a Typhoon EFI intake, reworked 65MM throttle body setup as for a fox, 70 mm MAF, 24 lb injectors, 93 Cobra ECU, shorty headers

North Racecars has the needed brackets and axles for going to a fox width rear axles in 5 lug with SN95 brakes

94-95 spindles in front work well but ream top strut bolt for more negative camber or use camber bolts. Or SVO rotors on 87-93 spindles or even SVO spindles if you don’t mind the rotor snout and bearing type

Either way SN95 balljoints in fresh replacement front control arms. Take the high friction stock style stuff and ****can it. SVO spindles require a MM balljoint adapter

You need V8 springs in front, double check rates of what you have in each car vs factory TRX or GT cars

Eventually front swaybar needs to be from TRX or its too strong. Wait until rear is addressed

rear springs in the 84 will be comparable to 93 cobra.

You will want a fox GT style rear swaybar but only if you add a panhard too and downsize up front

Easier and better IMO to swap to fox style brackets and pulleys. Under drive kit, use crank and alternator. Source a cobra style water pump pulley from Summit

more or less that’s what I would do. Make under hood look period — like it belongs

when you say swap the 86 wiring throughout what exactly do you mean?

[wraithracing]

when you say swap the 86 wiring throughout what exactly do you mean?

If you have an 86 5.0 EFI harness that is the easiest way to do the swap in a Four Eye. The 86 was the only year for the SEFI system, so that is the reason. Essentially its a plug and play. Any other harness will require modifications to work in the Four Eye, still workable, but not a plug and play like the 86 harness would be. Good Luck!

[Jack Hidley]

If you swap in the entire front suspension, you are going to have a number of problems.

1) The k-member and/or lower frame rails need to be modified on your car to fit properly. The 1994 k-member is 0.75" longer, so the rear mounting area is changed.

2) The overall front tread width is going to be 3.5" wider (60.1" versus 56.6"). Be prepared to do a lot of body work when each front tire is moved out 1.75".

3) The steering shaft will not fit. You will have to install an MMST-13 to connect the SN95 steering rack to the Fox steering column.

4) The engine is going to be moved forwards 0.75" from the normal V8 location in your car. Be prepared for fitment issues from this.

I would install a 1987-93 V8 k-member with your stock FCAs, the 1994-95 spindles, 1994 steering rack, MMST-13, MMBK-16 and MMBAK-4. Then you won't have to do crazy front fender work and you can use normal sized front tires and wheels instead of pizza cutters. With the engine in the normal V8 position, the car will also handle better. No matter what you do, install the k-member by itself first. Then install the engine. If you do the engine at the same time, this will make it very difficult to modify the k-member and square it to the chassis.

[4eyedblind]

I did not realize the 94 had this many changes. The 1988 setup I used in my 86 dropped in easily without mods. The additional track width proved to no be an issue with that setup. People think the Ks are the same between the early cars and 87-93 but they are not. I took measurements to confirm. The lower arms are the same length but the mounting points are moved outwards by about an inch a side on the 87-93.

[Jack Hidley]

Only 1987-93 cars with the HD suspension have the wider track. 99% of the 1987-93 2.3l cars don't have the HD suspension and therefore have the narrower front k-member and 10" front brakes from the 1985-86 cars. When selecting a k-member, you need to look at more than the year. You have to look at the suspension option also.

On 1987-93 cars, the HD suspension was mandatory if the car had a V8. With a 2.3l car, the HD suspension was an option, but was almost never selected.

[4eyedblind]

Right, I'm presuming V6 to V8 swap here, as the OP was talking about. I didn't realize you could get it with the four banger as an option. Does that also mean you could get the four banger with the 11" V8 brakes and GT steering rack as well?