Has anyone had any clearance issues with Flowtech headers on a 455? My headers are in, but I've noticed I've had some clearance issue with the proportioning valve. Any suggestions would be greatly appreciated.

 

No but the set I just used on the dyno was a bit pidgeon toed at the collectors, caused a problem hooking up the dyno exhaust system.

 

You will need to move the proportioning valve from the inside of the frame to the top of the frame with the flowtechs assuming this is a 68-72 A-Body

 

You have to reroute some of your brake lines and relocate the proportioning valve away from the headers. Possibly a little dimple here and there. Most have trouble around the upper A frame mounting area on the passenger side.

 

Would you happen to have a pic for visualization?

 

What are good 455 headers to use in order to have the clearance needed for the proportionung valve without having to make modifications?

 

I think most aftermarket headers in Olds A bodies require the valve to be moved.

 

x2

 

I just put my motor in and I used Dougs headers and was very impressed they are not cheap but well worth it all the bolts screwed in easily and they cleared everything and 3/8 flanges to with NO leaks I have used cheaper headers in the past and never did like them.