hey i just picked up this 72 f100 for 500 bucks. It has a 390 with a 4 speed and a dana 21 t case i think . The tag is missing and so is the shifter nob. If that is the right t case is it any good or should i toss it . I want to build a dependable all around wheeler . I got the truck running but it sounds like it has a dead hole , i will do a compresion test this week and find out . i heard that the 390 motors are known for the valves beating the seats out, is this true . thanks for the info in advance

hey i just picked up this 72 f100 for 500 bucks. It has a 390 with a 4 speed and a dana 21 t case i think . The tag is missing and so is the shifter nob. If that is the right t case is it any good or should i toss it . I want to build a dependable all around wheeler . I got the truck running but it sounds like it has a dead hole , i will do a compresion test this week and find out . i heard that the 390 motors are known for the valves beating the seats out, is this true . thanks for the info in advance

D21s are weakass single speed clunkers. Ditch the bitch if you can.

All the Fords made before '72-'73 didn't have hardened valve seats because they didn't need them, that's what the lead in gas was for, lubrication. Good chance that has been corrected if the engine has been overhauled in the last 30 years, which it has to have been if it is a 390 because Ford never put 390s in 4X4 pickups. Most 390s I have checked are 360s with a stroke of imagination.:D

The dana 21 tcase is all gear, no chain and is basicaly a dana 20 just a single speed which SUCKS!!!. I would suggest going with a 2 speed tcase like a np205.

hey thanks for the info guys, will the np 205 bolt up to the 4 speed or will i need a adapter. Or is there a specific model year to look for. With the dead hole i still need to do a compresion check but do you think i could get buy with just doing the heads or is it a wast of time and money . I am trying to do this on the low buck buget . I am located in northern cali but i am going to so cal for easter so if you have a running 360/390 for cheap let me know. Again thanks for the info

hey thanks for the info guys, will the np 205 bolt up to the 4 speed or will i need a adapter. Or is there a specific model year to look for.

The trans that bolts to the D21 is either a 2wd or some 1 of kind oddball, I don't remember which. Either way you'll need to get a FE 4wd NP 435, T-18 or C6.

thanks , thats what i thought

As said the tranny wont work, just find a tranny/NP-205 from another truck. The truck most likely has a 360 as mentioned above too. Watch the wheel bearings in the 9" in that particular year. I had several of them and lost axles going down the road and yes they had oil in them. I ended up going to the wider 9" from the 77-79 F-150 and never had problems afterwards. I am also willing to bet that if you look at the 3rd member in the rear you will find it has a 9 3/8ths rear. Easiest way to tell is the top right web will curl down instead of going straight acrossed like 9"s do. This will make a good wheeler, mine has alot more flex that most of the F-150's due to the narrower springs in the rear. The wider rear also puts more leverage on the leafs too but you want to truss the rear axle so you dont bend it.

I am located in northern cali but i am going to so cal for easter so if you have a running 360/390 for cheap let me know.

pm Masterbeavis, he has been working on an FE with the same problem and might have some advice or options for you.

Fresh heads on a tired motor=a tired motor with fresh heads..... This motor dropped a seat, the heads were patched up, but did not seal correctly...

Whereabouts are you in the Norcal area?

http://i14.photobucket.com/albums/a315/Masterbeavis/73-79%20Ford%20Trucks/73%20F100%204x4/390wow1.jpg
http://i14.photobucket.com/albums/a315/Masterbeavis/73-79%20Ford%20Trucks/73%20F100%204x4/390wow3.jpg
http://i14.photobucket.com/albums/a315/Masterbeavis/73-79%20Ford%20Trucks/73%20F100%204x4/390wow4.jpg
http://i14.photobucket.com/albums/a315/Masterbeavis/73-79%20Ford%20Trucks/73%20F100%204x4/390wow5.jpg
http://i14.photobucket.com/albums/a315/Masterbeavis/73-79%20Ford%20Trucks/73%20F100%204x4/390wow7.jpg

As stated about the trans, your trany will not work with the np205.... because the dana 21 adaptor is for a 2 wheel drive trany.

For the motor, I would suggest filling your dead cylinder with compressed air and rotating the crank to see if its a bad valve or rings/piston and go from there. If its a bad valve then you can have the heads reworked/replaced, if its the ring/piston then a rebuild is in order. Good Luck...

hey thanks for all the info, i am located in napa but i am in the sac area all the time

i did a compresion test all holes are 115lbs except # 4 it is 30lbs. Iam going to pull heads over the weekend see whats up but i am probably going to start looking for another motor for cheap.

if you have the skills to do it yourself a master rebuild kit isn't too much, obviously you'd want to have the block machined and a nice rebuild on the heads, but you'd have a much better motor when all is said and done then throwing in another old used motor. You could get a rebuild kit for .030 over and go from there. It'd be a nice fresh strong running motor. You could even put a different cam in it to get a nice flat torque curve that starts down low for a good wheeling motor. I know you said you want to do it on the cheap, but if you have the know how you could strip it all down to just the block, take the block and heads to a maching shop and have the work done, then re assemble everthing yourself and save yourself alot of money. I suppose getting a used motor for a few hundred bucks is alot cheaper, but if you plan on having it for a long time the rebuild would be the best idea for long term....

Hey, do the leakdown test I was telling you about. If you dont have the gauge, just adapt your compression gauge hose to the air hose... Pump it up, listen/feel for where the air is coming from. Valve problems will show up in the carburetor/exhaust, rings will show up in the PCV.

i will try the leakdown test you where telling me about this weekend . thanks again for the info

Hey, do the leakdown test I was telling you about. If you dont have the gauge, just adapt your compression gauge hose to the air hose... Pump it up, listen/feel for where the air is coming from. Valve problems will show up in the carburetor/exhaust, rings will show up in the PCV.


x2


Make sure both valves are closed, then hit it with air.

hey guys i found another moter and got it in so now it runs and drives . My next question is r=trans and t case ,If i find a nother 4 speed with a married 205 that was bolted to a 460/302 or any other moter are the bell hosings the same or can i use the one off of my 4 speed or what is the ideal donner to look for . Also my truck is a short bed so i guess a divorced unit wont work right ? Thanks for the help

If i find another 4 speed with a married 205 that was bolted to a 460/302 or any other motor are the bell hosings the same

Transmission from a 351M, 400 and 460 would work, smallblock is different.


or can i use the one off of my 4 speed

Yes, no problem. Engine side of the bellhousing is different but trans side is the same except for smallblock.

Also my truck is a short bed so i guess a divorced unit wont work right ?

No need for divorced t-case. Find the appropriate 4wd 4 speed with factory adapter and a 205 will bolt to it. One to look for would be a NP435/NP205 from a '77-'79 F-150/250. It will bolt to your bell housing.

if i decided to go with a c-6 and 205 all i need to do is find one from a 351m 400 or 460 right . Thanks for the info guys

if i decided to go with a c-6 and 205 all i need to do is find one from a 351m 400 or 460 right . Thanks for the info guys


Right...but remember from 77-77.5 (the intro of the 351M/400) a 250 will have a divorced tcase.

if i decided to go with a c-6 and 205 all i need to do is find one from a 351m 400 or 460 right . Thanks for the info guys

I got lost in all the 'ifn this and ifn thats' but if you still have the 390 then no, a C6 from a 351M, 400 or 460 will not bolt to it. C6s have an integral bell housing.

Three most common older gasser bell housing patterns:

FE.....330, 352, 360, 390, 410, 427, 428 etc,

Small block....some 289, 302, 351W, 351C,

Big Block.......351M, 400, 429, 460,

Not all these were truck motors.

hey guys i found another moter and got it in so now it runs and drives .

What engine did you get?

if you are talking about getting an NP435 all you have to do is change the bell housing.

you can take one from behind a 460 and put it behind a 300I6 if you wanted to...

if you are talking about getting an NP435 all you have to do is change the bell housing.

you can take one from behind a 460 and put it behind a 300I6 if you wanted to...

Ya, I think that's what I tried to tell him before but now he's asking about a C6. :confused:

sorry, you got me...
I am work and skimming...:flipoff2:

yes i should have been more specific. I still have 360 but what i was asking is if a c 6 from a 351m would bolt up to it . I understand the c6 has a integral bell housing and what i wanted to know was if it would bolt upto a 360. Thanks for the help

yes i should have been more specific. I still have 360 but what i was asking is if a c 6 from a 351m would bolt up to it . I understand the c6 has a integral bell housing and what i wanted to know was if it would bolt upto a 360. Thanks for the help



No 335/385 series C6 will NOT bolt up to a FE.

thanks that is what i needed to know.