I just bought a 1974 F-250 4x4, the PO said the original 360 blew, he installed a 30000 mile 390 in 1977. He said as of today that motor should have approx 50000 miles. He believes the 390 is a 1973/75

The motor is smoking more than I like and I think it has 150000 miles on it. It has a lot of gunk on it.

I did a little looking around and found these casting numbers.
Block C6ME
Heads C7AE-A (7C29) 8 bolt exhaust manifold pattern.
Intake C7TE 9425-F (7C29) "2 barrel"
Exhaust Manifold D2TE 9430 AA (4D8) Pass Side.

I was hoping for a 428. To figure the stroke, I placed a socket extension in the spark plug hole and turn the motor by hand, My ruler showed a little more than 3 3/4".

I'm trying to figure what this motor went to and it Factory Specs, such as horsepower and plug type.

Thank you for helping me!

 

66 block
3.75 = 390
pull a valve cover you might just have bad valve stem seals

 

Not sure there is a way to tell a car 390 from '66 to '70-'71 from a pickup 390, '68 to '76 without looking at the pistons. Your '66 coded block could have been used as OEM for several years after '66, ditto the '67 coded 2bbl manifold. The D2TE exhaust has to be from '72 or later, from a pickup as exhaust manifolds are car or truck specific.

It could be a used car 390 with the truck manifold added when the motor was installed. If so, and if it was a 2bb motor, it is probably a 9.5 CR motor, which was rated at 265 HP gross. Torque ratings seem to vary if I am reading this right:

FE Series Engine Specification Chart

Take that 265 down to about 212 or so net--approximately, just about.

Pickup 390s were rated about 208 iirc. I don't have a link to that speck sheet. They were low 8s for compression, and used a sunken flat top piston from the 410.

 

Thank you for the reply. yes I agree, the exhaust manifolds are from the 70's. Do you think the long block is matching or could it be a 1966 block and a 1967 head and intake??

Here's what the PO said:
The 390 was taken from a 350 that I salvaged and it was installed in that truck in about 1977. The motor came from a salvage yard in Wichita that Dad and I done a lot of business with, he had a frame and front end shop in Wichita.
It came from a vehicle with 30 some thousand mile on it. I put it in the 74 in about 1995. NEITHER TRUCK WAS driven as daily drivers is the reason for the low miles. The engine is a 1973/1975 I believe.

I was trying to make heads or tails out of it. Hard to understand what he was trying to say!!!

If you look at my past post, you can see pictures of the motor. I was under the impression that it was in better shape. It smokes a little and has an erratic noise, nothing like a bearing or rod noise.

 

The date part of the casting number indicates the engineering update year, not the year of manufacture. The block would have a date code on it, down by the starter area, pic here:

Ford 352, 390, 406, 427 and 428 Engine Blocks

IF the block and engine are original as OEM, it can be no newer than '67, but it could by almost any subsequent year. The date code would tell that tale.

As I read the story, the original source of the engine is unknown, other than it was a jy motor with supposedly 30,000 miles on it. Who knows?

If it's a gunked up smoker, it may be wore out, or just in need of valve seals, a bit of cleaning and a proper PCV system. Hard to tell until you take it apart, and at that point, why would you not at least do a ring and bearing job along with a valve job and seals?

IMO, at this point, it's just another FE motor, and the good news is it is probably a 390.

 

Yes, I agree thanks for confirming! I pulled the starter today and couldn't find anything on the wall, now I see where to look per your link, Thanks!

In your opinion, if I was to rebuild, I would like a good towing motor with good gas mileage. I already have a 69 Mustang w/ a 351C for thrills.

What do you suggest, 4 or 2 barrel and cam & springs. I would do a 3 angle valve job, basic bottom end, headers w/ 3" pipes.

App- 1974 F250 4x4, 4 speed (435), D60 front & rear w/ 4:10's

 

Check the head drains for crud - if the heads flood with oil, you will burn it like there's no tomorrow, as it'll go right down the valve guides.

Otherwise, rebuild and enjoy!

 

The only thing I can find near the starter is the letter "C" near the tab on the RH rear upper corner, just above the starter.


Further searching, I found that the Date Code is near the Oil Filter. I found the casting number 7C10 or 7010 ans a big "V" next to it.


Does anyone know what the "C", 7C10 and "V" stands for. Does the Casting number correlate with the heads and intake?

 

"7C10" as a date code would be March 10, 1967.
7 = 1967
C = third month, March
10 = day of month.

Sorry about the prior misdirection on date code location.

It is very possible the block, heads and intake manifold left the factory together.

Since the 390 didn't show in pickups until '68, it is very possible this is a car 390, and if so, probably a "Regular Fuel" 2bb motor with 9.5 compression.

In other words, yes, the block, head and intake casting codes are all consistent with the date code.

 

I would put an oil pressure gauge on it and let that dictate whether it needs a rebuild. If the bottom end is still solid ie carries good oil pressure than its most likely the dried out 40 plus year old valve stem seals

 

Today I removed the coil to fix both coil wires that were frayed.
Unbeknown to me, placed on the bottom of the coil bracket was the the Engine Tag.
Now I know exactly what I have which coincides with the above casting numbers.

The Tag reads:
390 67 8
7 D 311 A

Which means:
390 2V 265hp@4000, 9:5-1 Comp, 2V Carb, built on April 1967.

 

Excellent. Valve seals should fix the oil burning, and away you go. A 9.5 motor can make real power with the right cam and manifold/headers....