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help id'ing a 390

3K views 3 replies 2 participants last post by  FFR428 
#1 ·
Hi,

I just recently bought a 1962 Galaxie 500. It has a t-bird (t-bird valve covers and air filter) 390 in it. I have discovered this is not the original motor. I have been trying to ID it to no avail. It has 352 stamped on the block, and the letters/numbers 8F3F stamped between the oil filter and the cylinder head. I have a cracked exhaust manifold I need to replace. I have been told the year of the motor makes a difference when getting the correct manifold. Can anyone help?
 
#2 ·
The 8F3F sounds like the date codes. There would be no F on the end. It would be a number in most cases. The last number or 2 are the day of the month the block was cast. So maybe it's a 31 and not a 3F. So a 8F31 date code is a 68/June/31 or 3rd if the last number is just a 3. As far as the exhaust mains you'd need to get the casting number off them to see if they are the original or something later specific to the bolt pattern in the heads that may have just fit. Ford used 8, 14 and 16 bolt patterns on FE/FT heads depending on the application. As far as checking for a 390 you can measure the crank stroke. Put the balancer timing mark on TDC and remove #1 spark plug. Install a lenght of stiff wire or wood dowel and mark using a common guide edge. Then rotate to BDC and mark again and measure the distance between the marks. A 3.5" is a 352/360 stroke. 3.78" or roughly 3 3/4" a 390 stroke. And 3.984" or roughly 4" a 428/410 stroke. As for the true bore you'd need to measure it with a head off. Casting numbers if the block even has one are generic from that time. Could be one of many different bore blocks. But if you get a 3.78" stroke reading I'd bet the rest is a 390.

G.
 
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