SB R3 Crank

-
A

AUSA66

Well-Known Member
Joined
Nov 20, 2014
Messages
368
Reaction score
520
Location
Perth
Anyone still doing a 4.25 crank for the SB 2.1 chev rod size
 
Molnar makes a 4.125" stroke crank. Close but not 4.25".
 
Puts the motor way out of square and it won't like RPM's The ultimate would be a 4 inch stroke with a 4 inch bore. Or 4.25 stroke with a 4.25 bore . You'll need a race block or sleeves to safely do a 4.25 stroke. Remember with sticky tires use steel mounts to prevent block flex when bolted down. but always use a poly stiff spool type trans mount unless you have a front and or rear motor plates.

Block flex kills a over bored motor.
 
Last edited:
Oldmanmopar said:
Puts the motor way out of square and it won't like RPM's The ultimate would be a 4 inch stroke with a 4 inch bore. Or 4.25 stroke with a 4.25 bore . You'll need a race block or sleeves to safely do a 4.25 stroke. Remember with sticky tires use steel mounts to prevent block flex when bolted down. but always use a poly stiff spool type trans mount unless you have a front and or rear motor plates.

Block flex kills a over bored motor.
Click to expand...
Using a Kent Ritter siamese bore tall deck with Spool Mounts on engine & trans
 
You must log in or register to reply here.
-

Back
Top