@larryw posted:Ford shaped the exhaust ports of the Cleveland 4V head to work in Mustangs and the like, where the exhaust gas flow had to turn down quickly and stay tight to the block. This kept the ports low on the head. I don't think there's any other stock application where headers exit the head at the angle Pantera headers do. If you choose to stay with the Cleveland 4V iron head, that compromise is tough to overcome. You may want to consider some of the modern aluminum heads with raised ports before you have headers built. Or, if you want old school, Ford SVO parts, like the early C-3s, A3 or C302B.
Larry,
Thank you for your help, I have decided to follow your advice and buy new flanges for my existing headers. For the time being, I will try and space them as you described and see how that works. This will be an easy improvement until I have the budget for a custom exhaust and maybe even new aluminum heads.
My engine is not as comfortable in the upper 5k+ rev range as I would like it to be. It currently has a dual plane aluminum intake and a Holley 4160 600cfm carb. I bought a single plane Edelbrock Torker intake and I am also planning on upgrading to a 750cfm carburetor. I also have a new DUI distributor and wires that I will be installing at the same time. I hope that the engine will be more comfortable above 5000 rpm with these mods.
Once I get the car running again (I currently have the rear suspension uprights disassembled) I am considering upgrading to a new camshaft and I have been looking at some of the kits offered by Comp Cams.