Trans bolt Patterns
Thread Starter
Le Mans Master
Joined: Nov 2006
Posts: 5,032
Likes: 204
From: Greenwood Indiana
2021 C4 of the Year - Modified Finalist
C4 of Year Finalist (appearance mods) 2019
Trans bolt Patterns
Are the transmission bolt patterns the same on the early small blocks as they are on LT-1s? Are the crankshafts the same where the flywheel bolts on? I'm wanting to mate a ZF6 to a 70s 350 engine. 
Race Director
Joined: Feb 2004
Posts: 12,517
Likes: 19
The bellhousing bolt pattern is the same. Flexplate bolt pattern is different. 2 pc seal cranks have 1 bolt pattern and 1 pc seal stuff has another pattern.
Thread Starter
Le Mans Master
Joined: Nov 2006
Posts: 5,032
Likes: 204
From: Greenwood Indiana
2021 C4 of the Year - Modified Finalist
C4 of Year Finalist (appearance mods) 2019
Can an older style flywheel be mated to the ZF or does someone make one for this swap? 
Team Owner
Joined: May 2002
Posts: 24,337
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Yes.
I'm using a 2-pc seal motor with the ZF. Used my original 85 flywheel. I'm sure there are plenty of aftermarket flywheels that will work also. The ZF has an 11" clutch, my stock 10.75" flywheel is just barely big enough.
This may help you:
Ignore the 85 clutch and pressure plate, they won't work with the ZF.
I'm using a 2-pc seal motor with the ZF. Used my original 85 flywheel. I'm sure there are plenty of aftermarket flywheels that will work also. The ZF has an 11" clutch, my stock 10.75" flywheel is just barely big enough.
This may help you:
Ignore the 85 clutch and pressure plate, they won't work with the ZF.
