Hello,
I picked up a crate motor for my 70 Suburban project & am a little confused as to which block I actually have. The casting number is 12550313 with a date code of H306. It is supposedly a Mark V but does have a mechanical fuel pump & 6 bolt timing chain cover. So it looks to be a Mark VI block with Mark V bolt ons? I know that with the 8/30/96 date code that GM might have been mix-matching things together but I just need to know what exactly I have with this motor before I start adding any performance goodies to it. I picked the motor up for a great price & it only has 24,000 miles on it. Only upgrade that I can see they did was an Edelbrock Performer Intake. Any help would be greatly appreciated!
Bob
I picked up a crate motor for my 70 Suburban project & am a little confused as to which block I actually have. The casting number is 12550313 with a date code of H306. It is supposedly a Mark V but does have a mechanical fuel pump & 6 bolt timing chain cover. So it looks to be a Mark VI block with Mark V bolt ons? I know that with the 8/30/96 date code that GM might have been mix-matching things together but I just need to know what exactly I have with this motor before I start adding any performance goodies to it. I picked the motor up for a great price & it only has 24,000 miles on it. Only upgrade that I can see they did was an Edelbrock Performer Intake. Any help would be greatly appreciated!
Bob
