Past experience
I had the Custom (brand name) chrome sidepipes on my 350/370 LT-1 (1970 version) in my 68 vette. They looked and sounded great. During the first year, they started to turn blue in the engine compartment, and at the last piping bend behind the front tires. By the second year, they started leaking exhaust around the collector to exhaust tube connection (below the front of the doors), which accompained with louder exhaust and black exhaust soot at the connection. By the end of the 3rd year, they were rusting heavily in the pockets between the tubes where the exhaust tubes entered the collectors. This was from the outside. Also, by then, the 4" exhaust tubes themselves were rusting from the inside out. I had to replace the mufflers 2 times in 4 years, the second time didn't quiet the car much because of a bad fit between the exhaust tube and the muffler insert due to the corrosion. When they got so loud I could not talk to the person next to me, I scrapped them and went to rear exhaust.
I am again rebuilding the entire car and want to return to side exhaust. I have not yet decided to go back to the stock sidepipe covers with stainless steel mufflers or buy the Hooker stainless steel side exhaust headers. Hooker says their technology has come a long way, they now have reverse flow exhaust mufflers for the side exhaust and Patriot does sell heat shields for the Hooker side pipes. Have looked into the ceramic, and I like the reports on corrosion and heat resistance, but not the reports on the ceramic cracking after several (5-6) years. Also, they cost almost as much as the stainless steel ones. Have not seen them to be able to report on how shiny they look or stay. Again, have not yet decided, but am leaning towards Hedman ceramic side exhaust headers (Hedman PN 68281) and stock style stainless steel mufflers with stock style covers.
Also, I will be running Edelbrock Pro Flo-2 electronic fuel injection with Edelbrocks Performer RPM aluminum heads. Edelbrock recommends 1.7/8" tubes with their fuel injection and head combination to reduce backpressure. They say their components tested better with the increased flow/lower backpressure in the larger tubes. Your conditions may not be the same, but I would select my tube size primarily on engine performance requirements. I had plenty of room in my 68 engine compartment and cannot imagine an additional 1/8" larger radius will make that much of a difference. The Hooker tubes are 1.7/8" diameter, but have very long tubes while the Hedman headers are 1.5/8" diameter with much shorter tubes. Maybe this all balances out at the collector. Seems like at this level, if one is physically going be too large to fit, so will the other.
Another consideration, at least for me, is that with the Hedman header, the collector is inside the engine compartment and with the Hooker header it is outside the car below the doors. The Hedman configuration will make it possible for me to install the O2 sensor in the collector while the Hooker configuration must be welded into one of the header tubes (or located outside the car and visible). That means I will be sampling only 1 cylinder instead of 4 for O2 readings to the Fuel Injection ECM.
What ever you decide, hope you will post what you decided and how it has worked for you.
