Before I was running the Power Inc pipes, I was running the stockers and I ran 42.5 pilots in it along with 146.3 PTO, 145 Center, and 145 Mag. This was an extremely cautious way of going about it because I went up 3 jet sizes across the board on the mains. This was also due to the fact that I was running pretty lean jetting for the stock pipes so I wanted to be safe. If I were still running the stock carbs I would drop it down one jet size across the board and run 148.8 PTO, 147.5 Cen, and 147.5 Mag. You are probably safest going up 2 jets sizes from what you are currently at across the board th your mains. As for your Pilots, I went from 42.5 to 45 but I think it seemed pretty rich on the bottom end so I would've thrown the 42.5 back into it. As for clutching, you should first get your jetting dialed in and go from there. What you are going to realize with these pipes is they do make more HP and they are going to increase your stock clutching RPM's about 100 through the entire powerband. These pipes also perform very well at 8400 RPM and if you can get it to stay near those numbers you are going to be very impressed. Also with these pipes, the hotter they get, the more power you are going to make out of them. If you can purchase some pipe wrap for them or get them ceramic coated or block off some hood vents or one of the above, you should see better power out of the pipes and the sled. Let me know if you have any other questions.
-Matt
