1 5/8" tubing for the header is perfect.
I'm assuming you are still going to use the Holley HP EFI system.
If so you need the Ford 4.9 distributor that supplies a PIP signal and has no mechanical or vacuum advance.
I believe it was for the 1987 - 1991 engines. It will look like this with the gray module mounted on the side but the cap will be black.
The Cardone 84-2687MA should get you a new distributor with cap, rotor and module.
[image]https://static.summitracing.com/global/images/prod/norm/sgt-fd10_hb_m.jpg[/image]
The HP EFI has a cable that plugs directly into the distributor module. The Cardone 84-2687MA should get you a new distributor with cap, rotor and module.
The intercooler is rated at 550 hp and has the inlet and outlets are facing back towards the engine which I'm hoping will work for you.
It should mount directly behind the front grill so it gets plenty of airflow going down the road.