While doing a little bit of research on the block I was rebuilding I came across a lot of good info on the different TBI 350 blocks that came in these trucks. I figured I'd pass the info along.
All 87-95 Blocks Are Roller Ready (Even though they came with flat tappets)
There were two different TBI 350 blocks that came in the GMT400 vehicles.
1/2 Ton Trucks (Under 8600GVW) got a 2 bolt main block. These came with 9.2/1 Compression and 64CC heads. They were rated at 200HP and 300ft.
3/4 and 1 Ton Trucks (Over 8600GVW) got a 4 bolt main block. These came with 8.5/1 Compression and 76CC heads. They were rated at 195HP and 300ft.
There were also two different block castings. 638 and 880. The 638 blocks had deeper skirts in the piston bores. So they would make a good choice for a stroker build.
Hope this information helps a few of you out. I was a little bit confused at first when I took my oil pan off and discovered a 4 bolt main.
All 87-95 Blocks Are Roller Ready (Even though they came with flat tappets)
There were two different TBI 350 blocks that came in the GMT400 vehicles.
1/2 Ton Trucks (Under 8600GVW) got a 2 bolt main block. These came with 9.2/1 Compression and 64CC heads. They were rated at 200HP and 300ft.
3/4 and 1 Ton Trucks (Over 8600GVW) got a 4 bolt main block. These came with 8.5/1 Compression and 76CC heads. They were rated at 195HP and 300ft.
There were also two different block castings. 638 and 880. The 638 blocks had deeper skirts in the piston bores. So they would make a good choice for a stroker build.
Hope this information helps a few of you out. I was a little bit confused at first when I took my oil pan off and discovered a 4 bolt main.