Aww I feel so sorry about cold and reain, my heart bleeds ( as this ex-san diegan lives through a brutal 9 degree night....

Your ride sounds awesome, VAP tuned with both pulleys now E85... will be untouchable...

 

My vin is 618xx. I wonder if perhaps it was a build option or if it was applied automatically throughout a certain VIN range.

Ha ha, sorry man

 

i had a couple month downtime back when i did it and on a car that was reasonably new to me in that i had only driven it a couple thousand miles back when i did the intake valve cleaning.
so like Dave says, the butt dyno says "maybe"... but my first drive after reassembly was with a new smaller upper pulley (no tune loaded yet) so not apples to apples
my valves were caked with a thick coating that turned to miserably heavy tar with the chemicals. i cannot believe spraying chemicals into the intake would remove 100k miles of deposits, but who knows and it's logically that it's good for preventative maintenance as was stated
I'll admit, i was expecting a 50hp improvement with how nasty the valves were, but it didn't happen. must be the air gets through and the intake valves aren't the most restrictive element of the air pump that is the 5.0 s/c engine..
to safeguard for the future, i made an oil catch can to fit the tight engine bay. i made it custom out of copper pipe and fittings with copper pan scrubber media stuffed in and a drain on the bottom. I've drained the better part of a quart of fairly nasty liquid out of it, a few ounces at a time over the approx 8,000 miles since installing it. I have no idea if the intake valves have accumulated more deposits or not, but the catch can has prevented all that nastiness from being sucked through the intake.
there are two crankcase pressure valves - the one on passenger side is the high pressure one where most of the oil gets through to the intake. it's the one that connects on rear of pass side head area and routs to the top of the throttle body area. i cut that tube and patched in a catch can.