I will tell you from experience that the MAC long tubes suck. The reason for this is the primaries bolt to the head individually i.e. do not have a one piece flange and that makes it a huge pain to get them to line up and the header bolts to start. When they are new they just about bolt right up but after a few heat cycles they move all over the place.
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BBK's have a one piece flange that is 3/8" thick and keeps all of the primary tubes tied together and line right back up after being heat cycled.
I also had the MAC shorties on my Coupe and those literally got tossed in the trash. I have used BBK's on the car for over 15 years and they have performed very well. I did clean up the welds on in the ID of the flanges (removed some of the weld as it was overkill and restricting the opening) and open up the fire cones (2-1/8" opening to 2-3/8") which took a couple of hours with some carbide burr bits and a die grinder.
I do no know the part number for the MAC long tubes (checked the build file on the car) but you should check the BBK's out as they seem to have good reviews.