[1950Mercury]

Has any one had any experience with Patriot headers on a 66 GTO 4 speed car H8301-B part number. Fitment quality etc.

[1950Mercury]

Has anyone had any first hand experience with Doug’s headers D564 black stainless or coated headers as far as fitment issues etc on a 66 GTO 4 speed car. I’m just trying to avoid opening a can of worms. Or maybe just go for the HO headers that are supposedly designed for the early GTO’s. Are there slight differences on how Doug’s fit a 67 as opposed to 66. I see where some have had to modify brake lines.

[Gary H]

Originally Posted by 1950Mercury

Has anyone had any first hand experience with Doug’s headers D564 black stainless or coated headers as far as fitment issues etc on a 66 GTO 4 speed car. I’m just trying to avoid opening a can of worms. Or maybe just go for the HO headers that are supposedly designed for the early GTO’s. Are there slight differences on how Doug’s fit a 67 as opposed to 66. I see where some have had to modify brake lines.

On a 4 speed car the bellhousing needs to be trimmed on the passenger side to get an oil filter in. No big deal and can be done in 10 minutes with a saw saw.

[1950Mercury]

I am really starting to lean toward the Ram Air H O exhaust. So far from what I’ve read on a mild engine they perform well to about 5,000 rpm with good low end torque. And it seems usually only need to raise engine slightly and re route battery cable. For those running the H O manifolds how do they work out?

[gtospieg]

I've been running the HO manifolds for 14 years....no problems. Will be using them again on my current build.

[1950Mercury]

What body style are your h o headers on. Did performance improve?