It's a TURD and you don't see them around because they didn't work well.
The best intake out there for a SBC is the factory iron unit. They are excellent, and the runners, port volume, design, etc, perfect for what you are doing.
Even going to an Edelbrock Performer will hurt fuel mileage in many cases as it doesn't hold the heat as well as the iron unit. Heat helps atomize the fuel and warm up the incoming mixture, so a leaner A/F ratio will be needed for complete combustion.
I'd dump the SP2P and use a factory intake.....Cliff
PS: make sure to leave the exhaust crossover open.