91 gt 351w swap questions

driftguy2008 · Jan 5, 2013

Hey guys I might be buying a 91 gt roller with a 4 point cage, subframe connectors, eibach spring pretty cheap but it needs a powertrain. I have my buddy's 96 bronce that he rolled behind my barn and it has a 351w in it but we couldn't get it to run last year so we said f**k it and left it there and it's his parts truck now but he will never use the motor so I might try to get it off him for the cheap. So my question is how can I swap it in the 91 gt what do I need and what would be easier try and keep it EFI or go carb and so I need new heads if I go carb? I know I need a new intake and what carb would you run? I wanna throw a cam in it. I'm 17 so its gonna be on a budget but I think I can pull it off with less then $2k including the mustang and have a nice mustang. And it was originally a 5 speed car can you bolt a t5 to it or do I need a C4?

88LX5.Oh · Jan 6, 2013

A T5 will bolt right up to the 351. It would probably be easier to go carbureted with it but EFI would be so much better. No you wouldn't need new heads to go carb'd. Carb size I wouldn't go massive since all it would have done performance wise would be a cam and intake. I'd go with a 600 or a 650.

gearheadboy · Jan 6, 2013

Do a search for 351w swap. You will need a boat load of stuff. BUDGET is not the case really. Headers, oil pan, flywheel or flex plate, hood clearance issues, bracketry. Consider fuel pump/lines for carb v.s. EFI.. It is doable, just not cheap.

f8tlfiveo · Jan 6, 2013

Stay efi.. Carb is for race cars and old cars..it will prob be just as expensive and more of a headache. You can use the efi stuff that is on the vehicle now

gearheadboy · Jan 6, 2013

I hope you didn't think I was steering him toward a carb. Just things to consider in the cost. Options, lots of them.

ratio411 · Jan 6, 2013

Roller 351w!
Go for it!

Just remember that the 351 is 28oz imbalance.

It will bolt right in place of a 302 and only needs a few specialty items like oil pan and headers to fit a Fox.
The 5.0 wiring harness and sensors will swap over, assuming the Bronco sensors are different.
Tmoss can set the truck 351w lower up to accept a Holley upper for fuel injection, that would be the best setup.
You could use that chunk of change instead to buy a 351w GT40 lower, and top it with a Cobra/Explorer upper, but that wouldn't give you the kind of performance you'd get from the Holley.

Transfer the distributor from the truck. The 302 distributor will not interchange.
If you decide to refresh the engine or even just the heads, think about a set of GT40 heads from an Explorer.
When they are at the machine shop getting refreshed, have them open up the head bolt bosses slightly to accept the larger head bolts.

The Bronco accessory brackets are very user friendly, and similar to SN95 brackets. I would be all about trying to make those work for the swap. Otherwise, the stock Fox brackets may be able to work with mods. For example, Ford sells a bracket kit for using Fox accessories with a 351 that modifies the A/C mounting to make it all work.

driftguy2008 · Jan 6, 2013

So I need headers, oil pan, flywheel, flexplate, and other bs stuff. Can't I just use the flywheel and flexplate & balancer that's on the 351 already? And what's wrong with going carb? I could get a intake and carb for $300 used of my dads friend or spend $500+ easily on upper & lower intake manifold. And I could get gt40 heads for cheap at my junkyard and buy a comp cam to give it some balls and no be underpowered. How bad of fuel economy would I see with a carb vs EFI? If I get a decent about better mpg's ill go that way. I'm all new to this as I said in my first post I'm only 17 so actually buying parts and build budget combo that will get me my bang for the buck I'm all new to this. So if I ask stupid questions it cause I honstely don't know.

ratio411 · Jan 6, 2013

What transmission is in the donor Bronco?
If it is an auto, and you are going to put an auto in the Mustang, you might be able to use the Bronco flexplate, depending on tooth count vs the tooth count on your Mustang auto tranny.

If the donor is a manual, and you are using a manual in the Mustang, you could probably use the donor flywheel.

If the donor is one trans, and you are using the other trans in the Mustang (manual vs auto), then you need a flywheel (manual) or flexplate (auto) ANYWAY... So it isn't really an additional expense, but one you will have regardless.

You will get better economy with EFI. If EFI is more expensive, which I doubt it will be, the fuel economy would pay for the difference quickly. If you went with a GT40 lower for a 351w, and topped it with a junkyard Explorer upper (10-30 bux), then reused the rest of the Stang EFI, it should be cheaper than a new carb and intake, plus the mods on the car/engine that you will need to convert to carb.

gearheadboy · Jan 6, 2013

I got some expense and research in brackets and accessory drive components. It was a PITA. But you have a complete donor 5.8 set-up. I started with nothing. And you CANNOT use the Mustang flywheel, flexplate, or balancer. It is 50oz imbalance, where as a stock 5.8 is 28oz. Do a search under the engine swap forum. There is a ton of info. There are 1000 ways do do it.

NIKwoaC · Jan 6, 2013

ratio411 said:
Tmoss can set the truck 351w lower up to accept a Holley upper for fuel injection, that would be the best setup.

Does he completely recut the lower to work with the Holley? Because other than bolt pattern, the ports are completely different. I know people have attempted to reshape the lower's ports to match up to the Holley, but I didn't know that was something Tom did regularly.

ratio411 · Jan 6, 2013

gearheadboy said:
...you CANNOT use the Mustang flywheel, flexplate, or balancer. It is 50oz imbalance, where as a stock 5.8 is 28oz.

I was saying if the donor is the same tranny as the Mustang, then he may be able to swap.
The other point was that if the donor and Mustang had different tranny, auto vs manual, he would have to buy a flywheel/flexplate anyway, so cost or not, it was going to have to be done.

ratio411 · Jan 6, 2013

NIKwoaC said:
Does he completely recut the lower to work with the Holley? Because other than bolt pattern, the ports are completely different. I know people have attempted to reshape the lower's ports to match up to the Holley, but I didn't know that was something Tom did regularly.

I talked to him about doing it for me on one of my back burner projects, and he said he does it. Unless I misunderstood the depth of his work?

If you lurk through some google images, there are plenty of these reworked lowers to be seen, some horrible quality, some very nice.

gearheadboy · Jan 6, 2013

ratio411 said:
I was saying if the donor is the same tranny as the Mustang, then he may be able to swap.
The other point was that if the donor and Mustang had different tranny, auto vs manual, he would have to buy a flywheel/flexplate anyway, so cost or not, it was going to have to be done.

Oh I got ya. I misunderstood.

91 gt 351w swap questions

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91 gt 351w swap questions

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