I swaped from a TPI setup to a converted LT1 intake.
I got "new" #24 injectors.
I just starting to tune part time crusing ( got BLMS pretty *** at 128 on my 9th bin ) and I noticed a strange pattern.
After a tuning session I took off all my plugs to read them.
I noticed that my "front" plugs ( cylinder 1,2,3,4 ) got less carbon build-up then my "rear" ( cylinder 5,6,7,8 ).
Just like the "rear" plugs runs richer then the "front" ones.

Just to eliminate bad injectors ( not that its likley to have 4 bad injetors, but anyway ) I swaped the "front" with the "rear". Made some runs, same thing..

That made me think that I got uneven AIR distribution in the plenum.
When I mounted the intake I took extra care to gasget match the intake with the heads, so nothing bad there. Oh and the heads are brand new, so no bad vavle seals either.
Also tried swaping spark cabels.
The car is NOT eating any oil, and no smoke on startup or on acceleration.

What do you think? I cant think of anything else then uneven air distribution.

( the diffrence on the plugs its not HUGE, but I can truly se the pattern )..


Cheers

 

Yep. The front cylinders get more air than the back ones. I've heard about this happening before.