I'm going from a LB9 to a L98. The car is using a 1989 LB9 ECM. Which knock sensor should I use in the new L98? The LB9 had a 100k-ohm sensor and I've read the L98 needs a 3.9 k-ohm sensor. For what it is worth, the knock sensor that came out of the L98 is a 100 k-ohm as well, so go figure (I have no idea if the engine was running properly beforehand). Since my ECM is staying the same, should I stick with the 100 k-ohm knock sensor?

You need a 100k ohm ks, you might also check the part number on RockAuto to see if the esc is different.

You have to use a knock sensor that goes with the L98 (350) and match the ESC module to it. Not sure if a L98 knock sensor/ESC module pair would work with your LB9 ECM. You probably need a new tune.

The 1989 350 L98 knock sensor is #10456288.
The 1989 350 L98 ESC module: Alternate/OEM Part Number(s): 16052401, 16128261, 21647, ESC100

Cheers

Thanks. I will try the 100K as that is what came off the 350 and what worked on my 305 with that ESC.

I was under the Impression 305 and 350 esc modules were the same just the frequency of the ks was different.
see the above part numbers and get the correct esc module.
if you don’t you might chase false knock.
My friend was chasing this after changing to the 89 vette roller motor ks but still using his old 87 305 esc.