Has anyone got any comparisons on their cars times running closed cutouts versus open exhaust cutouts?

And even more what interests me, going from open headers to large dia exhaust with open cutouts?

I am going to put exhaust on my car first time since going to my 412SBC. I run 1 7/8 open headers w/ 3 1/2" collector.
We are going to put 3 1/2" cutouts and 3 1/2" pipe to performance mufflers(type not yet decided).

I guess the real question going thru my mind is do cutouts give the same performance as open headers or is there still a loss because of the added weight of the exhaust system and the restriction caused by the slight angle of the cutout?

I watched a buddy get his license and run a few 10.0's... dropped header mufflers and go 9.7's without any other changes.... turning's got him down to 9.4's. So yes, but depends on your combo by how much.

I only gained .14 seconds when I ran with open headers. 11.10 open 11.24 closed.

On my dad's old setup he had 2 1/4 duals and he usually picked up about .3 when opening his cutouts. That was when he ran 12.80's.

With his new combo there isn't much of a difference, maybe a tenth.