What years have these?? does any 88-95 350 chevy truck or car have them, or just the vortec 96 on up?

 

Some of the early TBI trucks did not have roller blocks. Most of the later ones did. They were not roller motors but instead just had the block provisions but had flat tappet cam. All 3rd gen TBI's were roller motors.

 

A longer answer:

96+ L31 (and probably the mini Vortec 305 L30 truck engine) got roller lifters. 1995 and earlier TBI truck engines (L03, L05) got provisions in the block casting for roller lifters but used flat tappet cams. This happened because the passnger car versions of the L03 and L05 got roller lifters, and the block casting for trucks was sourced from the same place as the passenger cars. Of course, the passenger car blocks lacked the drilling/tapping and caps for 4-bolt-main that the truck blocks got. The v8 truck engines from (guessing on the year) 1987 and earlier were all flat tappet with no provisions in the casting for roller lifters, because the passenger car engines didn't have them either.

So a truck-based TBI engine can be adapted for use with roller lifters by drilling/tapping the cast plateaus in the lifter valley used to retain the metal spider that keeps the rollers aligned to the cam lobes. But you would still need the spider plus the lifters themselves. HTH.

 

Sounds pretty funny that they wouldn't drill/tap those Spider Supports right from the plant... Are you sure about that? Not that I know one way or the other, it just seems odd that they wouldn't use a finished block to begin assembling from, no matter what the application.

 

IIRC only the passenger car blocks got drilling/tapping for the spider. My guess is that, after the common machine work was done, that the passenger car blocks went to one final machining stage for the lifter spider drilling/tapping, and the truck blocks went to a different final machining station for the 4-bolt-mains. The trucks and cars were usually assembled in different factories, so it's not a stretch to think that the engines for each were sourced, finally, from two different lines that did the final machine work.

 

well do you think that a 94 model truck have those drilled in the block??