Horns????????????? HELP

I have a 3 clinder 30 yamaha and a 1976 20mercury (both fishing motors) and i want to build a horn for them but HOW i need some specs!! i have a old quincey horn on a 25 merc and it covers both cylinder ports! And i have a old double horn that was homemade thats rusted out and the holes where it goes over the ports are small so if i was to build one lets say a single for the 20 merc how big skould the holes be on the plate that the horn comes off of?????? and if i make a double for a two cylnder hoe big does those holes need to be?? when i say holes im saying on the plate where the exhaust cums into the pipe!! if anybody can help i would be greatfull and who builds them and do they have a website???

i see u figured it out

No not really! If you get any info halla at me im sure theres some1 out there that knows something about horns and how to build them. Theres just to many ppl out there that runs them .. HHHHHHHHEEEEEEEEELLLLLLLLLLLLPPPPPPPPPPPP guys!!