4.8 LS swap in a 1975 coupe

DFlikks · Jul 7, 2025

Hello all. I know this might be a hated topic but im looking for some other people (assuming its been done) that have swapped an LS engine into a mustang 2

I got a clean 75 for a good deal. Ive been hunting for a good shape roller for my 4.8 ls thats been in my shed and always liked the look of the 2’s so i figured it would be a neat way to spruce up a “hated” mustang.

Ive got no issues with cutting/fabricating, as i know it will be tight. Looking to pair up the nv3500 behind the motor.

I just wanna know pan options that fit around the crossmember/rack if there are any, how tight the transmission is in the tunnel or if it needs some cutting and the space for headers and exhaust.

I appreciate any insight

2Blue2 · Jul 7, 2025

DFlikks said:
I just wanna know pan options that fit around the crossmember/rack

V8 Mustang II uses a crossmember specific pan that hugs the crank for half the length of the 302.

DFlikks said:
how tight the transmission is in the tunnel

V8 Mustang II uses the tiny 141 tooth flex plate / small bell housing C4 and tunnel is narrow

DFlikks said:
got no issues with cutting/fabricating,

Sudden Death used a 460 ci and they made it work, so you can make ur LS work too.

DFlikks said:
up a “hated” mustang.

Not everyone hates it, I think its an older generration thing, who remember the end of convertables, big blocks, and even V8s, in Mustangs.
We like em Here!

2Blue2 · Jul 7, 2025

Oh and Welcome Aboard.

DFlikks · Jul 7, 2025

2Blue2 said:
V8 Mustang II uses a crossmember specific pan that hugs the crank for half the length of the 302.

V8 Mustang II uses the tiny 141 tooth flex plate / small bell housing C4 and tunnel is narrow

Sudden Death used a 460 ci and they made it work, so you can make ur LS work too.

Not everyone hates it, I think its an older generration thing, who remember the end of convertables, big blocks, and even V8s, in Mustangs.
We like em Here!

Appreciate the insight. I did get a front sump pan for the motor, so that should clear the rack/crossmember no problem. My main issue i think will be if the transmission fits in the tunnel, but nothing a grinder and welder cant fix

DFlikks · Jul 31, 2025

Been waiting on most of my parts to come in, but the front sump pan and universal mounts showed up. Was able to get the car in the shop and the engine bay cleaned out. Motors test fitted in, just gotta cut and weld the mounts tomorrow.

Gonna be tight with the intake manifold to the hood. After everythings bolted in ill have to see how it fits or if ill have to go with a shallower manifold. Will also have to do abit of banging/cutting for the 4l80 to fit in there. And some custom work up front for the exhaust/coolant/intercooler piping. As expected

LILCBRA · Aug 1, 2025

I guess it depends on how much of a "sleeper" look you want to maintain, but there's no shame in modifying the hood for clearance. You could always cut it and install a scoop of some sort, or you could buy a fiberglass cowl hood from some places, like this:

1975-1978 Mustang II Fiberglass Cowl Hood

classicautoreproductions.com

Their other hood might work, but you'd probably want to do a bit of measuring before committing to buying it.

I didn't aee it mentioned, but what rear end are you planning on? You'll most likely be good if the car has an 8 inch, but I wouldn't trust anything stock otherwise with the power you're looking at.

DFlikks · Aug 1, 2025

LILCBRA said:
I guess it depends on how much of a "sleeper" look you want to maintain, but there's no shame in modifying the hood for clearance. You could always cut it and install a scoop of some sort, or you could buy a fiberglass cowl hood from some places, like this:

1975-1978 Mustang II Fiberglass Cowl Hood

1975-1978 Mustang II Fiberglass Cowl Hood

classicautoreproductions.com

Their other hood might work, but you'd probably want to do a bit of measuring before committing to buying it.

I didn't aee it mentioned, but what rear end are you planning on? You'll most likely be good if the car has an 8 inch, but I wouldn't trust anything stock otherwise with the power you're looking at.

That hoods actually a pretty good option, thanks for sending that!

It came to me with a 9” ford rear end in it. As far as ive been told it used to have a 302 in it and was used as a drag car. The guy i got it from pulled that and put a 2.3turbo in it, which was blown up and removed when i got it

DFlikks · Aug 1, 2025

Got the motor mounts measured, cut and welded in today. Looks good. Now waiting for some more parts to show up to start the exhaust/intercooler piping and fitting the transmission

DFlikks · Aug 21, 2025

Been waiting on parts to come in but the flexplate finally came and i was able to bang and fit the tranny in. Actually has more clearance than i though. Just had to grind the rack down abit as the pan was rubbing in one spot.
Next is the tranny crossmember, going to fab one off the stock one, putting the harness in, remote oil filter and fuel line/pump so i can do a test start. Once it test starts good ill start fabbing up all the turbo piping
Also ordered an ls6 intake off ebay so i can actually fit under the hood

4.8 LS swap in a 1975 coupe

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2Blue2

will be trying this sex one when I can find it

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will be trying this sex one when I can find it

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LILCBRA

I wish I didn't have all of these balls in the air

1975-1978 Mustang II Fiberglass Cowl Hood

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1975-1978 Mustang II Fiberglass Cowl Hood

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