352 or 390
Freshman User
Joined: Jan 2000
Posts: 35
Likes: 0
352 or 390
If the motor is really the trucks original it would be a 352. If not pull the no.1 plug bring the engine to TDC, insert a small 1/8" wooden dowel in the hole onto the piston top, then bring the motor to BDC, this will give you a good enough measurement. The stroke of a 352 is 3.5" and a 390 is 3.78.
Elder User
Joined: Aug 1999
Posts: 910
Likes: 0
352 or 390
My 390 has a single pulley/harmonic balancer. I know it's a 390 because I had the heads off and it's definitely a 3.78" stroke.
Another difference is the Bore. A 352 has 4" bore, a 390 has 4.05" bore.. that might be difficult to measure considering old motors may have been bored larger in the past. Can you access the casting numbers from the crankshaft with the oil pan off? I have a listings of the different FE cranks in my How to Rebuild a Big Block Ford book.
BBT
Another difference is the Bore. A 352 has 4" bore, a 390 has 4.05" bore.. that might be difficult to measure considering old motors may have been bored larger in the past. Can you access the casting numbers from the crankshaft with the oil pan off? I have a listings of the different FE cranks in my How to Rebuild a Big Block Ford book.
BBT
