1991 350 non-roller block

[jtrux]

Based on what I've read the blocks in the 87+ range were roller blocks that are not drilled for the roller lifter "spider".

Does anyone have a pic of the lifter valley to confirm this?

Just curious if it is as simple as drilling out a few holes to convert to a roller.

 

[b454rat]

I want to say the only roller blocks were Camaro's Vette's and other cars. Later years of truck motor had the bosses, but weren't drilled.

 

[frankin5]

I have a truck roller block 1990 blazer motor. They have the block, just no rollers were used.

 

[USSkoval]

Many of the truck blocks were 100% set up for the roller cam hardware. But, there also were some that had zero roller cam provisions at all. The only way to know for sure is to take a look.

 

[1-ton]

The 1988 to 1991 TBI original truck assembly line engines did come with all the riser bosses drilled and taped for roller cam lifter valley retainer plate, and the roller cam retainer on the front of the engine block. The blocks that do not come with all the riser bosses drilled and taped are GM Goodwrench replacement crate engines. If you see an engine with all the riser bosses for the roller cam, but are not drilled and tapped then this is probably a GM crate replacement engine, and not an original assembly line engine. The original assembly line engine also came provisioned with mechanical fuel pump mounting as well, but not the GM Goodwrench crate replacement engines.

There are videos on Youtube on how to drill and tap the riser bosses on GM crate replacement blocks for roller cam retro-fitting.

 

[USSkoval]

The 1988 to 1991 TBI original truck assembly line engines did come with all the riser bosses drilled and taped for roller cam lifter valley retainer plate, and the roller cam retainer on the front of the engine block. The blocks that do not come with all the riser bosses drilled and taped are GM Goodwrench replacement crate engines. If you see an engine with all the riser bosses for the roller cam, but are not drilled and tapped for them then this is probably a GM crate replacement engine, and not an original assembly line engine. The original assembly line engine also came provisioned with mechanical fuel pump mounting as well, but not the GM Goodwrench crate replacement engines.

There are videos on Youtube on how to drill and tap the riser bosses on GM crate replacement blocks for roller cam retro-fitting.

Still not all of them though. I've got a TBI block that doesn't even have the riser bosses.

 

[1-ton]

Still not all of them though. I've got a TBI block that doesn't even have the riser bosses.

My original assembly line 1991 small block 350 for my truck has all the riser bosses drilled and tapped. I have the original assembly line block sitting on an engine stand in my shop. I bought a GM Goodwrench replacement engine for my truck, and it has all the boss risers for a roller cam, but none of them drilled and tapped.

 

[USSkoval]

My original assembly line 1991 small block 350 for my truck has all the riser bosses drilled and tapped. I have the original assembly line block sitting on an engine stand in my shop. I bought a GM Goodwrench replacement engine for my truck, and it has all the boss risers for a roller cam, but none of them drilled and tapped.

I've got a replacement block from a '91 truck, but I don't recall the date code of the block, but it doesn't have the stand offs. I also have an '88 dated block that was a GM replacement and there's no stand offs.

I don't mean to say that they are common, just that they are out there. I think I only have two of them because I'm unlucky, lol.

 

[jtrux]

Very interesting. I know the history of my truck and the engine is original so now I'm curious as to what I have. Thanks for the info, fellas.

 

[Chevy305]

It's a total crap shoot on the truck TBI engines. The only way to know is to pull the intake and/or timing cover to look. Some had bosses drilled and tapped, some had bosses but not drilled, and some had none. Roll the dice