98cobrakiller

bought a lq4 from a buddy with a totaled gmc 2500 yesterday to start on my 408 build. where is everyone drilling the knock sensors in the block. and i believe i also have to drill a hole for the altenator bracket?

batboy

iTrader: (6)

Is this LQ4 a gen III or gen IV? If it's a gen III, then you use the LS1 valley cover and LS1 knock sensors. If it's a gen IV you drill and retap out existing threaded holes in the side of the block, then extend the wires (you can get pre-made extensions). This pic is a LS2, but it's the same for most gen IV blocks.

Tainted

iTrader: (9)

And depending what harness you have you may need to extend the wires. like if you have the early block with the sensors in the valley and you move them to the side you will need to extend them.

98cobrakiller

whats the difference between the the gen 3 vs gen 4 blocks

Tainted

iTrader: (9)

Sensor locations, the gen 4 lifter tray area has a notch so they are gen 4 specific trays and the casting process was better so they are normally a bit better to bore etc

98cobrakiller

ok thanks for the help