Hi everyone I need some answers I have a off road pro chamber with boomtubes on my gt I would like to know which diameter mac long tube header to use the 1-3/4 or the 1-5/8. I'm going to a muffler shop to have them put the headers on and use my pro chamber instead of flipping the bill for a new mid pipe. My question really is what size will be better for my setup on a n/a motor eventually I will be putting on comp cams. If anyone can let me know I would appreciate it thank you.

 

I would stay with the 1 5/8 primaries. It will help keep exhaust velocity high, aiding in low to mid range power.

 

Thanks I've been looking online and I only have seen 1-3/4 headers. I'll keep looking to see if the 1-5/8 headers are more for the older body syles or if only mac makes that size only for the s197 mustang, thanks for the response.

 

What did the shop quote you for install? Expect to pay upwords of $600. Do it yourself. Lots of write ups about how to do it. Only takes a weekend.

 

I have a friend that used the shop before, they gave him a real cheap price for a custom h-pipe for his truck but for me I dont know yet but for paces around here in tampa I heard they do great work and charge decent prices.