Hello i have a 1963 f-100 but the engine was replaced a few years later with a much bigger engine. i found C8ME-A stamped on the engine block itself. I know it stands for a 1968 Mercury Engine but i still need help identifying the exact engine size. Are there any for sure easy ways to determine the size?

 

How many bolts in the valve covers? Do the valve covers go over the edges of the intake? If you have 5 bolts and the covers go over the intake, that's an FE.

There is no easy way to tell displacement externally. You can measure the stroke with a wire through a plug hole. IF it's a '68 Merc, it is probably a 390. However that's a big "IF".

Check the valve covers, count up the bolts and let's go from there.

 

I am already assuming it is a 390 due to its size and the year, but yes the valve covers do have 5 bolts and go over the intake.

 

Is it a 2 or 4 barrel? Stock or aftermarket?

 

It is a 2 barrel and im pretty sure it is stock.

 

IF it was in a 1968 Mercury, IF the 2BBL is original, then it has to be a 390. Most were 9.5 "Regular Fuel" motors, but Mercury did offer a 10.5 "Premium Fuel" 2bbl 390.

In the Mercury line in 1968 there would be 390, maybe 427, and maybe 428. No 2 bbls on 427 or 428 motors.

Beyond this--your question: "Are there any for sure easy ways to determine the size?", can only be answered by tearing it down and measuring the bore and stroke. You can measure the stroke externally with a wire or dowel, but the bore is an "open it up" proposition.

 

Alright thank you i already had an idea that it was a 390, and this has helped me narrow it down more and at least now i can play with it more.

 

C8ME-6015-A = 1968 block casting number, pertains to both Ford & Mercury. Could be a 390 or 428, but the only way to verify is by measuring the stroke.

390 = 3.78" / 428 = 3.98."

428 uses the same harmonic balancer as the 390, but the flywheel or flexplate is 428 ONLY!