I want to use a holley 750 on my 455. it has a stock toro intake.
what do i need to do for this? i know most of you will say not to.
1) I like how holley's look a lot more
2)just got done rebuilding it
3)I know it like that back of my hand

All of those will be opposite for the q-jet. it would most likely need a rebuild, and i know nothing about it.

 

One of two ways adapter plate from spread bore to square bore. Or replace the intake with an aftermarket intake. Changing the intake would be worth wild. The toro intake is shorter than other stock 455 intakes. So the toro intake will restrict the engine a little.

 

The sqarebore-to-spreadbore adapter is such a poorly flowing piece that it defeats the whole purpose of changing the carb. Get the correct intake or you're just wasting your time and money.

 

My 455 ran better and faster with a q-jet than the 750 holley I had on it.