headers and exhaust

[allons]

I've got a 72 with a 350 RamJet FI and 4 speed trans. I want to put the best headers and exhaust on it for performance and reliability. What about the long tube headers? Should I ceramic coat the headers inside and out? What size of exhaust tubing? What else am I not thinking about? Your thoughts would be appreciated. Thanks

[Rufton]

IMHO.
The most important feature for street headers is thick flange and fit.
I'd sacrifice some horses to facilitate install and maintenance.
Over sized tubes can negatively affect scavenging and torque.
I'd use smallest tubes that accommodate max actual rpm.
Use longest header bolts that fit to resist backing out.
I prefer ceramic coated SS. The ceramic must be sprayed at a certain thickness on prepped substrate which is hard to control inside tubes. There is a special tube spray gun but it's expensive.

[piecesparts]

You can purchase ceramic coated long tube headers that will fit for the money that you may spend purchasing the headers, then sending them off to be coated and returned. Price of course is a major thing to many, but a good set of headers is worth their money, no matter what. I have a set of ceramic coated cyclones on my 84 truck and they are standing up very well. My 2011 daily driver has a set of long tube jet coated KOOKS on it, but I wanted the performance of the KOOKS name, so I spent the money for that. I would also look at installing the header flange bolts with teflon tape on them, to keep them from bbacking out, once set in place. I have been using teflon tape on my header bolts for years and it really works to keep the bolts in place and they do not get galled up on removal. I agree on the smaller tube sizing for the headers over that larger tubes, this keeps the velocity of the exhaust flow going and helps with cleaning out the cylinders and charging them with a new air/fuel mix. This should be followed up with an exhaust that keeps the exhaust flow moving and not just laying about inside the tubing, to ensure that the headers are working properly. Use a cross-over either an "H" pipe of a "X" pipe design to keep the torque in the proper range for driving on the street. Do NOT oversize your piping for your exhaust, keep it where the collapse of your exhaust fumes as they cool will create a negative pressure for the scavenging effect.

[allons]

I almost hate to say this with obamageddon opon us, but the price of the headers really isn't the issue . . . . . it's the performance. I think I'd like to have 2 1/2 diameter tubes with Flowmaster 44s and an X pipe. Size matters, but performance first. What do you think? Have you got a good header recommendation that you would share? Thanks

[Rufton]

Sorry, not much help but:

In reality, to many factors to easily estimate header performance.
Almost need a test track, trial and error runs, and full pocket.
When looking at headers for bike I was lucky that magazine ran tests of all the top headers vs stock.
Turns out stock was very good and the different headers tended to move curve around with no real average improvement.
Granted if you were racing near red line you could pick best but it would cost power on the low end.

You can use performance software to be pretty sure headers and exhaust pipe isn't too restrictive.