Vintage Mustang Forums banner

1 - 20 of 32 Posts

·
Registered
Joined
·
185 Posts
Discussion Starter #1
A buddy of mine has a 68 FB I might be taking off his hands. It’s a project but still drivable, it currently has a 302 but I want to put a 390 in it. Is it just a matter of changing engine mounts or is there more to it than that?
 

·
Registered
Joined
·
1,006 Posts
Lot more than motor mounts. Bell housing, clutch, flywheel, pressure plate, transmission, exhaust, all engine front brackets, pulleys, radiator, hoses.

Why a 390? Why not stroke the 302 to 331 or better? Or step up to the Windsor block series and make a stroker 427? Still would need front engine accessories, radiator, etc. but it'd be 100-150 lbs lighter than the 390.

Sent from my SM-N960U using Tapatalk
 

·
Registered
Joined
·
185 Posts
Discussion Starter #3
Lot more than motor mounts. Bell housing, clutch, flywheel, pressure plate, transmission, exhaust, all engine front brackets, pulleys, radiator, hoses.

Why a 390? Why not stroke the 302 to 331 or better? Or step up to the Windsor block series and make a stroker 427? Still would need front engine accessories, radiator, etc. but it'd be 100-150 lbs lighter than the 390.

Sent from my SM-N960U using Tapatalk
I’ve got a 390 and thought it would be cool to do a big block ??‍♂
 

·
Registered
Joined
·
3,141 Posts
James, I love the FE series. Yes, it fits. But there are ALOT of small details to go with. So, you can do it, just know what your getting into. What 390 do you have ? Is it ready to go ? LSG
 

·
Registered
Joined
·
2,245 Posts
Front suspension will have to be changed... the 302 suspension will be hard pressed to handle the weight of the 390. Worth it though. Go for it.
 

·
Registered
Joined
·
10,265 Posts
A 390 Mustang definitely has a high cool factor. As mentioned, swapping a 390 into a small block Mustang is non-trivial. While I have nothing against big blocks, I've never been a fan of the 390. They typically don't have the power to justify their extra size and weight. If you mod the 390 to put out some serious power, then it might be worth the hassle. I would agree the post above. If you want more cubes, build a 347; lighter, smaller, easier to work on and it bolts up to everything you have at the back and at the front.

But hey, it's your car. If you really want to drop in that 390, go for it. Just be aware it's a major chore now and into the future.
 

·
Registered
Joined
·
35,950 Posts
Front suspension will have to be changed... the 302 suspension will be hard pressed to handle the weight of the 390. Worth it though. Go for it.
The only thing that's different in the front suspension between a small block and a FE car is the coil spring rate. Even the sway bar is the same size.
 

·
Registered
Joined
·
4,263 Posts
The only difference in suspension between the big block and small block are beefier coil springs- everything else in the suspension is the same.

Motor mounts, bellhousing, transmission crossmember, transmission, shifter, radiator (outlet orientation) and Z bar are a few things that come to mind that are big block specific.

I have a 428 FE in my '68 fastback. The cool factor of an FE is hard to beat, but man is it a pain in the ass to work on. There's absolutely zero room to service the header gaskets and you need to be a contortionist to adjust the clutch linkage. But, when done right, is flipping awesome.

If you're dead set on doing the swap, I would highly recommend stroking the 390 and ditching as much cast iron as possible. Trick flow recently came out with a set of aluminum heads and they're fantastic. The Edelbrock heads are basically a copy of the OE Cobra Jet heads but in aluminum.

Also, keep in mind- if that 390 is out of a truck, you will not be able to use the cylinder heads. You need the 390 GT or Cobra Jet style heads. All other heads have a different bolt pattern for the exhaust manifolds/headers and will not fit in a mustang.

I say do it :).

IMG_3499 by armon7, on Flickr
 

·
Registered
Joined
·
1,018 Posts
The FEs also have extra sheet metal bracing for the shock towers.
 

·
Registered
Joined
·
618 Posts
I converted my car to an FE about 10 years ago. I did not have any issues finding the correct parts, but the parts were definitely more expensive than the same parts for small blocks. It looks like the guys that have already responded listed most of the parts you'll need to change. Make sure you use a good fitting pair of headers that fit the 390 heads.

Also its worth noting the standard 390, 390GT and 428 heads all have different exhaust bolt patterns and the exhaust ports may be different as well.

Not sure what the 390 you have was pulled from, but you'll need to make sure the oil filter housing is for a car and the filter mounts vertical.

I would definitely switch out the intake to an aluminum and possibly even the heads to reduce weight.
 

·
Registered
Joined
·
5,396 Posts
Unless you are trying to clone a specific car, I don't think there's any reason to put a big block in a Mustang that didn't already come with one, especially an FE. Those engines have a lot of quirks and do not suffer fools. In my opinion, 390s are harder to get power out of than a 351w. I've seen built 390s dyno and the number always shocks me. Try to find a 500hp 390, I'd love to see it. A 351w on the other hand? And if it's a stroked Windsor like a 393 or 408? If I had to bet big money on a race and could choose my engine, I'd take a 393w over a 390 FE any day of the week. Forget about it.

The FE is not like a BBC where you can make 800hp without even thinking about it. A 385 series big block might be a different story in a drag car, that might be worth the time, money and effort. But not a 390.

Don't get me wrong, original big block cars have an undeniable cool factor. I'm not trying to talk down on those at all.
 

·
Registered
Joined
·
69 Posts
390 all the way. But then I'm an FE guy. A properly prepared 390 will put a smile on your face.

Go spend a minute on the FE forums...
 
  • Like
Reactions: Daisy

·
Registered
Joined
·
5,740 Posts
The FEs also have extra sheet metal bracing for the shock towers.
To be clear for a 67 390 stang there was no extra "bracing".

But '68 I think for a FE 428 stang, the shock towers had a "wrap around" extra plate.

I have a 67 factory 390 vert, the shock towers were stock same as a 289 no extra bracing (wrap around plate). However when car went to bodywork I did have them weld seams up.

To add to Happystang's list:
Driveshaft, exhaust, if you want power steering - pump diff, rear end was always 9" for FE, disc brakes perhaps, speedo cable. If you do a 4 speed - trans cross member unique to FE trans.
But the feeling of the FE torque done correctly is awesome.
 

Attachments

·
Registered
Joined
·
35,881 Posts
The FEs also have extra sheet metal bracing for the shock towers.
Not until the 428CJ in 1968 1/2. Prior to that, no wraparound. Not that it's a bad idea, by 1970 Ford was using it on all sorts of Mustangs.
 

·
Registered
Joined
·
35,881 Posts
To be clear for a 67 390 stang there was no extra "bracing".

But '68 I think for a FE 428 stang, the shock towers had a "wrap around" extra plate.

I have a 67 factory 390 vert, the shock towers were stock same as a 289 no extra bracing (wrap around plate). However when car went to bodywork I did have them weld seams up.

To add to Happystang's list:
Driveshaft, exhaust, if you want power steering - pump diff, rear end was always 9" for FE, disc brakes perhaps, speedo cable. If you do a 4 speed - trans cross member unique to FE trans.
But the feeling of the FE torque done correctly is awesome.
Like any other engine, maybe moreso, the 390 is sensitive to distributor advance timing. Make sure the distributor is professionally set up.
 

·
Registered
Joined
·
3,141 Posts
James, yes, you CAN use the 390 truck heads. But, if you do, you'll have to buy headers with that bolt pattern, so don't think that you HAVE TO buy the 390 GT heads, you don't. You can also consider aftermarket aluminum heads. Blue Thunder, Survival and BBM and Pond all offer what you need. As to the 500hp 390, yes, they're out there. But you have to have them done buy someone who undersatnds the quirks of an FE, as one of our men stated, the FE does not suffer fools. MOST 390s get built with the wrong pistons, thats why so many 'built' 390s are dogs. You MUST get the piston choice correct. 99% of parts uppliers and shops will try to give 390 'truck' pistons, which although they are flattopped, will give you something like 7.8 to 1 compression. How do you think thats going to do for power ? The 390 responds very well to some valve upgrades, you can line the original 3/8 guides with bronze and then run 11/32 stem valves, 2.15 intake and 1.65 exhaust works nicely. You need a BlueThunder 427MR if you are running an aluminum intake, and you MUST run headers. The factory exhaust manifolds in an FE Stang kills 50hp ! If you can find the latest Engine Masters, the Classic Big Block winner was a 390 FE that made 594 hp. And if you DO choose an FE of any kind, there is some oiling work that is CRITICAL. Is isn't hard, you just have to know what to do, and how to do it. LSG
 

·
Premium Member
68 Mustang Coupe
Joined
·
3,300 Posts
Oh, you mean Windsor to FE.... I thought you was swapping chevy engines here by the title.....
 

·
Registered
Joined
·
1,018 Posts
And here I thought I'd seen the extra "wrap around" plate on my shock towers. I'll have to check next time I'm at the barn.
You might also want to consider a good export brace and Z-Ray's under-engine brace to help with the extra weight and torque.
I'll second what was said about engine bay space, or the lack of it. I have small hands and working around the engine is problematic. But, IMHO it's worth it. Give due consideration to what you plan to do with the car when deciding between an FE and a 351w (stroked or not). I'd put a list together of all the parts you will need and price them out. As said, the entire driveline might need to be updated. The sticker shock of the FE might change your mind.
 
  • Like
Reactions: Broke

·
Registered
Joined
·
2,487 Posts
Well be warned FE also stands for [email protected]!n& expensive,and unfortunately the stock form 390, other than the open the hood cool factor was not outstanding by itself..

If you want to do the swap, I'd say go ahead and do it.

You can wake-up a 390 with edelbrock heads and a performer RPM intake and shed a good amount of front end weight at the same time
 
1 - 20 of 32 Posts
Top