just wondering how good are the stock 496 exhaust with the stainless risers at stopping reversion will they work on a stock 420?

not an expert,but i think the bolt pattern is different...according to a lot of guys,with a little rework,they should still fit...there's no provision for throttle/shift bracket...i bolted mine on the transom,as i changed my 454 for a 496

yea i have them bolted to my current 330 it was more work than you would think to get it done right but thinking about a future upgrade to a 420 and wondering if i will have a problem with reversion