10. The blocks have a bellhousing pattern nearly identical to the older classic Chevy V-8s. There is an extra bolt hole at the top of the block that many older transmission bellhousings do not have, and a hole on some older bellhousings like TH350 and TH400 at the 2 o'clock position that these blocks do not have. Some people add a tab to the bellhousing at the top to tie into the block, though most have found no issues with deleting these bolts. Many of the truck engines use an iron block whereas the LS1, LS2, LS6, and LS7 all come with aluminum blocks. However there is a new 6.2L truck engine known as an L92 that comes with an aluminum block.