None that I ever saw listed. It is tight as it is in the area between the exhaust port and the spring towers. The larger the size the more the port would be squeezed off without a sweeping bend coming off the header plate.
I dont see a big problem with 1 5/8" headers, as long as it's a 302. we ran 7.0's (1/8) with Hedman 88-300 long tube headers. I think I once saw a set of 1 3/4" made for early mustangs (Hooker) but I dont know if they still make them or not.
Sorry did not post the info on my car The towers are cut and it has a 351w in it. I am rebuilding the 351w going 30 over and 11.3-1 comp set of AFR 185 Alum heads just would like to put the bigger tubes on it But don’t find any listings for 1 3/4 that will fit even with the towers cut there 2 tubes that come close to wear the control arm bolts to the tower
