The first split Chevy offered was the one in the 53 Corvette and it was a one peace model with a internal block of plate. The good thing is, it is verry rigid and can be bolted on with the intake verry secure. The bad thing is the price 300$ like the one on ebay in the moment to 575$ that i saw in a corvette shop.
Mike Yoder of Kansas Kustoms does a split for me and I have to say it is a great peace of craftmanship and I would do it any time again.
The sound is great, it looks vintage (almost stock) and it keeps the heat riser so you don`t have to go with the ugly heat plate and tubes as you need for the Fentons.
There will be no notable difference in sound and performance between the two models.
Talk to Mike, he will do a great job for you and it is the cheapest way to get a split.
Frank