Now this is for a '67 Galaxie but I would think the answers should be the same as on a Mustang though the Galaxie is a heavier car. I've got a stock 390 T-bird Special (4bbl carb, Z-code) engine in my Galaxie. It is backed by a 4 speed top-loader. If I keep the stock intake manifold and 4bbl carb, would I see any gains from installing headers or would I lose power/torque on the street.

What if I upgrade to a better intake and carb with the swap to headers?

If I would do headers, what size primaries would be good? 1 3/4 inch or 2 inch primaries?

 

if the car is mostly original i would not modify it .. you would be disappointed in most any performance mods as it takes many hundreds of horses to make a car that big feel really snappy ... just use it as a torque monster / tire frier ..

 

Yes but you should have a complete dual exhaust to go with it. I would talk to the header manufacturer on size. My guess is if your going to keep the current heads, 1 3/4 would be fine.

I agree with HOSS429, a car that big you might not notice a big difference but it's good start. It will make most future mods that much better.

 

Thanks for the replies.

I'm really on the fence about modifying this car. The car is basically original, in decent shape with 71K on it and has been family owned since my dad factory ordered the car back in 1967.

I was concidering "period correct" performace type upgrades for the Galaxie but since I also have other cars to play with (2006 Mustang GT and the '66 Mustang(which started out as a 6cyl)) that I feel better about dumping more mods on, it might be a good idea to just keep the Galaxie more stock (as suggested by Hoss429).

Thanks again!