J57ltr said:Here are the measurments that I have from these three different manifolds.
89' Tbird cast iron manifold. Mildly ported
ID of primary minimum dims 1.7165" X 1.1540" this is kind of an hour glass shape and the dim is up and down and across the smallest opening horizantally.
2.055" ID on the outlet.
96' & up Tbird manifold. Stock SST
1.3030"ID 1.4715"OD Has bends with a OD of 1.379" X 1.486" oval
1.7805"ID on the outlet could probably go to 2.00"
99' & up Mustang tubular manifold . Stock SST
1.235" ID on the inlet. In order to make this figure larger you would need to weld a bead around the outside while still leaving room for the bolt to attach it to the head.
1.4455" OD primary tubes gets larger as it starts from first cyl to last cyl.
1.7410" ID outlet maybe able to open to 1.8" and it would take rewelding the outside of the flange to the tube to open it any more.