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???