Pipe tops out at around 8k with that setup so horrible gearing, not jetted/tuned/timed correctly, that clutch not needed with that low rpm pipe for a stock 2 shoe with thick springs would work fine,
I’m sure you’re not base spaced 3 mm and decked 3mm or have a 3mm counter sunk head either which is needed for treats kit as well as casematched right, all in all your missing 10 mph easy,