Fabio421

What about the knock sensor holes? I've got an 85 block in my garage and it appears to have the same knock sensor holes as the later engine. I don't have a later block to compare to however. Please enlighten me as to the differences.

Thanks

PorKen

S4-up have different valley block plugs, with a 8mm threaded hole.
AFAIK, there is no part number for this plug. It can only be sourced from a dead engine.

Earlier 16 and 32V engines have one hex shaped plug with a 6mm hole, and two round plugs with an allen key hole.
There is a thread somewhere where someone drilled and tapped the early plug in-situ to fit a sensor.

Pre-S4, if you have the stock TB/MAF housing, you can only fit one sensor, at the front.