Lets dispell a few myths about the new LS1/6 powerplants

[NataSS Inc]

Originally posted by Mr.Fixit


I haven't had one apart, I still play with antiques mostly. What is the difference? I read 18 degree heads, but those can go on an old SBC. What are the differences?

The biggest difference is that the LSX series motors are "O" rings motors. You wont find a single paper or metal gasket on anything other than the heads. Having the right torque on EVERYTHING is imparitive. I.E. on an old SBC intake you can pretty much just throw it on and reef the bolts down and it will be fine. On the LSx intake that use rubber "O" rings everywhere the intake HAS to be torque in a specific pattern and a specific inch/lb and then done again a second time at a higher inch LB. If your off by 1 bolt in the pattern or a couple inch lbs the motor will never seal. the same for the TB, valley cover, water pump, and oil pan. They actually have a special tool kit that cost a stinkin arm and a leg just so you can properly put a motor together.

One of the major differences about the LSX heads is the intake port. the SBC intake ports are almost square, where as the LSx heads are thin and very tall. almost like a long rectangle standing on the short end. Here is a picture of my stock head, intake ports. My new heads have ports that are considerably larger. Wish I would have got a picture of those before I bolted them on, they are aweful purdy!


The port design makes for higher flow capabilites over a SBC head. the stock LS6 head makes use of a sodium filled valve to reduce valve train weight allowing for higher revs.