[Roush #1]

I have the same engine (#444) with a T-56 transmission and have tried a Pro Systems carb that was built for my application. It was good for just a bit more than a tenth of a second and a couple of mph in the quarter mile, all of it coming from half track on. Eighth mile times are nearly identical. Best times are listed on my profile sheet.
I find the original vacuum secondary carburetor a little more drivable on the street, but there is a difference on the drag strip. I use the original (green dot) carburetor on a daily basis and get a little better fuel mileage with it.
I also have three inch exhaust with two inch primary tubes. Be careful with the large exhaust as it is easy to oversize this combination. Mine likes a little back pressure and runs best with Car Chemistry muffler inserts.
I have over 25,000 miles on my engine and have had no problems.
Hope this helps.