I know there is quite a few threads about this swap but I have just a few questions regarding my specific swap. Any help would be greatly appreciated. Let me tell you what I know and maybe you guys can help.

Let me tell you why i'm doing this swap first before everyone just says to use the 408 as a boat anchor and rebuild the 390.

I bought a 72 ford f100 a couple years ago which has 156,000 miles on the stock motor. It has the Borg Warner t18.


This is the current photo.

The motor starts to puke oil from every possible opening once warmed up. I was contacted by a friend whose wife is making him clear out the garage so she can park their new minivan inside. He had a 79 bronco (pretty bad shape) and a fully rebuilt 408 which he was planning on using in the bronco later. I told him that I would buy the motor from him but I didn't really need the bronco. He said that it was a package deal and he would deliver it from just over 300 miles away. I got the bronco and the motor for $800. He works in a machine shop and put lots of work into the motor. First of all he put in a 400 crank and bored .030 over. He used hyperutectic pistons and located a pair of 4v closed chamber heads. He said that he gasket match ported and polished everything else. I don't know too much about that though. He built it with the 2bbl intake manifold and said to use the stock exhaust manifolds so it will have more torque.

I don't have the money for a full rebuild on the 390 that I would really like to do, otherwise I would have started it already. From what I have read, I need a bellhousing from a big block, engine perches from a 77-79 f100, and a flywheel from a 400. That is what I am sure of so far. I don't know if the clutch from the fe will bolt to the 400 flywheel. I also don't know of the crank was drilled for a pilot bearing. It came from an automatic in the bronco.

I am a bit of a newbie here so please be gentle. Any advice it greatly welcomed and appreciated. I have more pictures

 

check out and if any question. for my application i'm having a thicker flywheel built for my application. lot more torque than standard 400. get the thickest flywheel you can get to keep your clutch splines contact as much as possible. mine i started with is .820 thickness. only about .300 clutch spline contact with this clutch setup, stock mock up. will be going to a centerforce application. the bigblock zf has a 1 1/4" input shaft. normal stock is usually a 1 1/16" dia. need to get correct clutch for big block 460 11" or 12". check your flywheel and verify which you have. some flywheels have both bolt patterns in flywheel for 11" or 12". check out photos and drop a message!! I think in the end you will be happy and believe a worth while application. its a lot of trouble but keepin old iron alive isn't easy sometimes! On your application I belive you need a 400 bell housing. the input shaft difference going into back of crankshaft is your biggest issue and the 1 1/16" splines not really a issue if correct bell housing. If I remember correctly about 1/2" difference. it all about getting a proper spline contact at clutch and input shaft. bolt together with tranny on and check you input shaft and verify your input shaft is in back of crank and if in their about 1/2" to 5/8" your good. if sticking out need to find proper bell housing for your application. 1 1/16" input shaft is the norm for your application for clutch. hope this everything. O yeah some clutches will fit but no room for clutch fork if wrong clutch. If standard diaphram clutch should be no problems. jsut remembering stuff as i write. catch you later and if I forgot something somebody drop in and help out, forgetting stuff!

 

I haven' pulled the 390 from the truck yet. I don't think I will be needing the fe flywheel. I am at the stage now where I am planning it all out. I have a 79 bronco which I can use whatever I can from. I don't think the engine perches will work from it since it is 4wd and I'm only 2wd. I located a bellhousing at a scrapyard for $50 and it's already been sand blasted. I just figured on asking around before I got a flywheel. I'll probably have mine pulled in the next couple of weeks. Thanks for the info. Do you think I will have any issues mating the 408 with the t18 through a big block bellhousing?

I have the 79 bronco if you need any parts for your build.

 

Justin, I see a couple things here. First have you considered resealing the 390. New valve cover gaskets first, then the intake if it's leaking. I have the same going on with my truck trying to keep the concrete clean. The FEs have a lot going for them, weeping oil & leaking out on the drive is in that list.

Second while the 400 wasn't much from the factory, a rebuild can produce a pretty good engine. If it were me swapping the engine in the C6 would come with it. Damn a full grown Ford truck than can't shift it's own gears is my motto.

The less expensive reseal of the FE would be my first choice as long as it isn't knocking.


guluk




John

 

And as long as it doesn't have a lot of "blow-by"

 

I love the raw power from the 390. Unfortunately while it's running there is a steady stream of oil coming up the dipstick tube now. The oil breather has smoke pumping out and oil leaking from the seal around it. It has a very light knock and also blows oil from the distributed seal and rear main seal. I just put on a new intake and 4 bbl about 5 months ago so the intake seal and valve cover gaskets are new and don't leak. I can drive it for the 8 miles to work and it's already a quart low. If you pull the dipstick tube out, there is light smoke coming out also. I'm afraid I'll have to rebuild it if I want it to run any longer.

When I was offered this motor, I jumped on the deal because it was a great price. I wasn't quite sure of how hard it would be to do the motor swap but I didn't want to kick myself later for passing up a motor for that price.

Do you think it was a bad move? I just figured that the price of all the machine work along with all the other necessary parts for a 390 rebuild would cost more than paying $800 for a good motor and a few hundred dollars more for some additional parts to make the swap happen.

I won't be offended if you say I should have just rebuilt the 390. The motor came with a 79 bronco project. I know how hard that model is to find so if nothing else I can sell the bronco to fund my rebuild. Like I said before, I welcome any constructive criticism but I think the 390 is too far gone.

 

Justin a qt. in 8 miles is a lot. Do you have a good pcv valve in the passenger side valve cover hooked to the carb base, that is doing a good sweep of the engine? Vented oil fill cap on the drivers side, good pcv on passenger, good vacuum from carb base and in most cases you can stop smoke from dip stick.

You said that you swapped intakes, was it using oil like that when you swapped it?

Have you done or can you do a compression test?

You just swapping the intake calls for a clean inspection of the top of the block on the rear. Do you have a hand mirror that you can use with a light to look for oil wetness top rear of the engine?

I want you to rule out fixable oi leaks before rebuilding or replacing.




John

 

Thanks for the help John. I borrowed a compression gauge tonight and I'm getting on average from 95-115 lbs on all cylinders except #3. It was only getting 35-45 but not consistent. I pulled the valve cover and discovered that the intake valve doesn't seem to be opening. The plug was oil fouled when I pulled it.

When I did the intake, I put on all new everything including the oil breather, vacuum lines, and pcv valve.

Do you think I might have a broken intake lobe or maybe I really screwed up when I did the intake?

 

Justin, I don't mean to be disrespectful or bust your chops, but there are enough out of the ordinary things going on at the same time to warrant further investigation. Just because you just replaced and sealed the new intake install doesn't mean it will not leak. Don't ask how I know.

I think it's time for a second opinion to help you.

Where are you located, there could be some help by another member or a recommendation for a good shop.



John

 

Thanks for the info John. I probably could use another opinion. I think I will probably end up just pulling the motor and rebuilding it either way. I enjoy the teardown and rebuild. I also enjoy making my truck different than the others which is why I think dropping in the 408 would be a good challenge. There is a vast quantity of older ford trucks here and finding parts hasn't shown to be too difficult yet.

I'm in Amarillo, TX but I haven't seen too many other members from around here. In the interim I think I would like to keep mine running like its supposed to until I have rounded everything up for the new motor. I am only 30 years old and 11 of those years were spent bouncing around all over the world in the military. I have a pretty steep learning curve and if you knew of someone in my area, assistance would be appreciated.

 

Justin, Thank you for your service. I am afraid that I don't know anyone in your area.

I really think your engine is saveable until proved differently.

guluk




John