I have a K-Code 350 engine in my 1988 GMC Sierra 3/4 ton pickup, and everything is stock. The engine is whipped and needs replaced. The motor is an L05, but I don't know if it's a 2-bolt or 4-bolt main. Does anybody out there know for sure, and some details on the motor. I want to be sure that I order the correct long block. If I have a choice I'm leaning towards the 4-bolt main long block for durability purposes, I just want to make sure that it bolts up with the stock bell-housing and that there isn't any difference.
1988 GMC Sierra 2500 4x4 Engine Question.?
- Thread starter Rustynail
- Start date
Molson02536
New member
It's impossible to tell from the outside for absolute sure whether this is a 4 bolt block or not. In many cases the same casting number is used to make a two or four bolt block, then they acquire different part numbers. The only way to tell from here is to pull the pan and count bolt heads.
For knowing if it's a the roller cam, or not. The casting number offers some but not complete help. The casting numbers separate blocks that aren't provisioned for a roller from blocks that are provisioned, however, having a casting number for a roller provisioned block does not a guarantee it has a roller cam in it.
The casting number can be found on the rear of the block just below the head surface on the driver?s side. Also, the last three digits are usually cast into the right (starter/passenger) side of the block, however if you're staring at a "...148" as we'll see this ain't much help. A problem you could encounter is that there is a flat tappet block and a roller that both end with the numbers 148. The casting 14101148 is a flat tappet truck block, however the slightly different casting number 14011148 is a roller provisioned block. Is this a GM eye test?
The casting numbers here are for production blocks manufactured from 1986 to the end of GenI/GenII production. For 350 flat tappet blocks look for casting number 10045727, 14079287, 14088548, and 14101148. These were used mostly in trucks but do appear in passenger cars from time to time. They DO NOT include casting or machining provisions for a factory roller cam and cannot be retro-fitted with the factory roller cam hardware.
Roller blocks are more complicated because even though the casting number indicates the block is provisioned for a roller cam, it doesn't for sure mean the block has a roller cam. But a factory roller cam can be installed to one of these even if it currently has a flat tappet. For 350 roller tappet blocks look for casting numbers 10243880, 14011148, 14088526, and 14093638. The 880 is the L31 Vortec block, it appears in late 1995 production without Vortec heads and with TBI. In its 1995 incarnation it's provisioned for a roller cam, but like the other roller blocks in trucks, prior to the 1996 model year it might be fitted with a flat tappet cam.
Hope this helps, and you may want to upgrade your L05 for better performance and economy like turning it in to a 383.
