Too much horsepower

[Pranav]

Got the car on the dyno (will post dyno sheet later today).

My usual, trustworthy dyno was booked up, so I went to a dyno I once went to a couple of years ago; back then with the LT1 I had issues with this dyno randomly reading high on torque, hp was definitely high; had me about 15/20hp/tq off once I visited my usual dyno later that season after I felt everyone was pulling on me hard.

Since then this "sketchy" dyno has moved locations but it's the same dynojet, so who knows.

Long story short initial un restricted run was 279hp/307tq. They did mention they were about 0.5 off on AFR with their wideband; according to it I was hovering around 12.0:1.

I shoved a restrictor donut inside my LT1 airbox outlet, took it from 3" ID to 2.25" ID, then made four more pulls; averaged roughly 275hp and 308tq roughly. Going from a 3" inlet to 2.25" inlet seemed to do nothing?

I'm going to visit my usual dyno this Friday.

I'm going to order a smaller series of intake donuts to be safe, but planning ahead in the worst case this dyno was indeed accurate, how do I take 15ish HP out of a motor without killing the torque too bad?

Sean has the same motor as me, runs 261/310ish; but he has a more restrictive exhaust with a restrictor insert.

It is very easy for me to modify my exhaust to accept a restrictor, but will likely visit the next dyno on Friday with just more intake restriction as I likely will not be able to modify the exhaust in time. There is time after that dyno before the next race if I still have a problem.

Worst case if I'm still high on hp on the next dyno, theories on intake vs exhaust restriction?

I'll post up the dyno sheet later today to see if you guys have any doubts over the dyno's accuracy, seeing that 0.75" of intake restriction seemed to do nothing, but being a first ever WOT run on this motor the ECU may have been learning and picking up HP at the same time...

Additional note, I usually run 75w90 gear oil, for this run I had 80w90, ran out of time to change it to my usual 75w90; was just running junk 80w90 to get any crap out from the rear end from the last failure/rebuild. Not sure if that makes a difference.

Additional note #2; forecast has a probably 30*F increase in ambient temp this Friday over today.

Additional note #3: dyno said it was 53*F ambient; out door temp was just barely crossing 40*F; not sure how these are supposed to be setup, didn't feel cold in the shop but had two big doors open.

Definitely don't want to start the season on the wrong foot, don't expect me to ask for a free pass unless I really have a real problem...