Welcome to the site.
There are no wide base 2X4 manifolds that will accept modern carbs without adaptors. There is a fairly large selection of old school manifolds that are found once in a while at swap meets and there are usually some on e PAY.
That said, what are you actually trying to accomplish? Are you looking for WOW factor at car shows or do you want the car to actually be faster? Dropping that much carburation on an otherwise stock 292 isn't going to be that effective in increasing performance but it will cost some real money.
A lot of us on this site will be happy to help out with good advice on better performance from your Y if you can give us a better idea of what you are trying to accomplish.
Doug TThe Highlands, Louisville, Ky.