360 to 390 conversion
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 785
From: Simi Valley, CA
Cars:
1966/71 390 = C6AZ-6303-B .. Crankshaft-2U.
1968 427 = C8AZ-6303-B .. Crankshaft "Iron"
1965/69 390 All High Performance Vehicles: C8AZ-6303-B
Needsmorecoffee.
Joined: Oct 2004
Posts: 3,624
Likes: 2
From: CT
My Merc MPC shows the C6AZ-6303-B as a 1U 428 crank?
And the C6AZ-6303-A is listed as 66-70 390 2U crankshaft.
And yes the * C8AZ-6303-B as All HP Vehicles 390-427-428. 428 app listed as need special pistons. My guess 406 pistons there.
But I'm not sure what if any difference there is. I will find out though. Hope you've been well Bill. Always a pleasure.
Sorry to jump in here highjack the OP's thread.
Senior User
Joined: Sep 2004
Posts: 223
Likes: 1
From: Rexburg,Id
Don't forget the cam! I stayed with the stock 360 cam when I changed to the 390 crank and 4v pistons, and it's not all that impressive. It has a lot of low-end torque, but that's all; when you romp on it above 25mph, it just doesn't set you back in the seat. I'm going to a mild performance CAR 390 cam this winter.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 785
From: Simi Valley, CA
Must be an older than a 1969 parts catalog, cuz...
C6AZ-6303-B was later replaced by C9ZZ-6303-B = 1UA 428 Crankshaft.
The problem with old parts catalogs is, the part numbers are also old.
Ford updates 10's of 1000's of part numbers every year, and before I post one single part number on FTE, I have to verify if the number wasn't replaced at some point.
Thankfully, I have all the catalogs on paper and microfiche slides to enable me to do this, for without the O-S-I (OBSOLETE-SUPERCEDE-INTERCHANGE) Catalogs, I'd be SOL on FTE!
I now have the super rare and next to impossible to find 1960's early 70's Master Cross Reference Catalogs (from Pasadena Ford-they never threw anything away!), which enables me to decode cylinder head ID numbers, and any other part, mechanical or body, that has an ID number on it.
C6AZ-6303-B was later replaced by C9ZZ-6303-B = 1UA 428 Crankshaft.
The problem with old parts catalogs is, the part numbers are also old.
Ford updates 10's of 1000's of part numbers every year, and before I post one single part number on FTE, I have to verify if the number wasn't replaced at some point.
Thankfully, I have all the catalogs on paper and microfiche slides to enable me to do this, for without the O-S-I (OBSOLETE-SUPERCEDE-INTERCHANGE) Catalogs, I'd be SOL on FTE!
I now have the super rare and next to impossible to find 1960's early 70's Master Cross Reference Catalogs (from Pasadena Ford-they never threw anything away!), which enables me to decode cylinder head ID numbers, and any other part, mechanical or body, that has an ID number on it.
Needsmorecoffee.
Joined: Oct 2004
Posts: 3,624
Likes: 2
From: CT
Mine is a Mercury 65-72 1975 final edition. The 1UA SCJ 428 crank is missing the little balance weight on #4 or #6 (can't remember which one off hand LOL) counter the 1U and 1UB CJ both have. The 1UA used with the short capscrew LeMans rods put the counterweight on the nose with the SCJ crank spacer. Because of the added weight of the LM rods. This I'm sure you know. So that's odd they replaced the 1U number with the 1UA number. I'd think it would reference the 1UB instead? LOL!!
Boy I'll have to double check my book. I remember you telling me about all the number changes and the OSI catalogs. Good thing your here to keep it all straight!!
Boy I'll have to double check my book. I remember you telling me about all the number changes and the OSI catalogs. Good thing your here to keep it all straight!!
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