289 - 302 crank
- Thread starter simonjrwinter
- Start date
Lynn Larsen
Lynn Larsen
Simon,
If I am not mistaken, the 289 crank had just a hair less stroke than the 3" stroke of the 302. As to other differences─ journal (both rod & main) widths and diameters, one/two piece main seals, thrust bearing location, etc. ─ I couldn't say, but I am sure someone will fill in the blanks.
Lynn
If I am not mistaken, the 289 crank had just a hair less stroke than the 3" stroke of the 302. As to other differences─ journal (both rod & main) widths and diameters, one/two piece main seals, thrust bearing location, etc. ─ I couldn't say, but I am sure someone will fill in the blanks.
Lynn
The 289 had a stroke of 2.87 vs 3.00 for the 302. The cranks will interchange. The 289 block has a shoter cylinder and with the 302 crank installed you could get some rocking of the piston at BDC or break the skirt of the piston. The very early 302 blocks also had this problem (1968) but was fixed later on in 1968 production. The rear main seal will not be a problem as long as it is a 2 piece seal crank. I don't believe you can use the 5.0 crank in the 289/302 block due to the 1 piece seal of the 5.0 crank. I hope this helps.simonjrwinter said:
Jim is right, both cranks can be installed on a 289 block. However, there is 2 kind of 302 cranks. The early heavy (until 1981 I believe) that are 28OZ externally balanced (like the 289) and the last (1982 and after) that are 50OZ externally balanced (they are lighter). It means that if you keep your 289 flywheel and damper, you have to select a 302 crank prior 1982 that is 28OZ balanced 
The 302 Boss is the better 302 crank, being forged steel vs cast for the 302-4V. The 1969 unit was cross-drilled and the 1970 wasn’t. They are, however, expensive and hard to come by.
I believe the harmonic balancers are different between the 302&289: C8AZ-6316-A on the 302-4V, C9ZZ-6316-B on the 302 Boss, and C5AZ-6316-A on the 289. The 289K (HP) had two different balancers: pre 8-20-64 C3OZ, and C5OZ after that date, but whether they interchange, I don’t know.
If you put a 302 crank in your 289 block, be sure you also use both 302 rods and pistons to keep the 0.015" deck height clearance the same. Best OEM choice would be 302 Boss rods C9ZE-6200 B, D, or F. They are forged steel, spot faced vs broached, and use 3/8" vs 5/16" bolts.
This is what happens when you ask what time it is around here. Somebody like me tells you how to build a watch!
I believe the harmonic balancers are different between the 302&289: C8AZ-6316-A on the 302-4V, C9ZZ-6316-B on the 302 Boss, and C5AZ-6316-A on the 289. The 289K (HP) had two different balancers: pre 8-20-64 C3OZ, and C5OZ after that date, but whether they interchange, I don’t know.
If you put a 302 crank in your 289 block, be sure you also use both 302 rods and pistons to keep the 0.015" deck height clearance the same. Best OEM choice would be 302 Boss rods C9ZE-6200 B, D, or F. They are forged steel, spot faced vs broached, and use 3/8" vs 5/16" bolts.
This is what happens when you ask what time it is around here. Somebody like me tells you how to build a watch!
