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I know this has been discussed numerous times. I’ve got a 73 manual and over the last two years have been bringing it back to life as when I bought it the car didn’t run and had sat for approximately 20 years. I’ve got the car to the point where I can drive it and enjoy it although it’s missing something. I’ve been doing research on this forum about side pipes and have decided to go with the hooker side pipes with sts high flow inserts. I thought I read on one of the threads that there is modifications that need to be made to the skirts (that’s what I’m calling them unsure if this is the proper term but it’s the chrome things that cover up the frame rail.) Is this true and if so is this only necessary to a specific brand of headers and side pipes. I have kept the car stock and any changes I’ve made I’ve kept so it can be reverted to how the car came to the factory. Before I spend the money for sidepipes id like to know if the skirts need trimmed down because if they do indeed need modifications I will order different skirts and molest them and not the originals.
p.s. I’m 21 years old and my 73 has been my dream car for the longest time. It feels good living out my dream.
Eric congrats on living the dream especially so early in your life. Enjoy it!!
With regards to your question I just had to clean up my side pipe install on my 1969. First all I can address is original GM style side exhausts installed on a 1969. Yours being later year and aftermarket exhaust may need more or less modifications.
You will need to trim the edges of the lower fender and below the door panel to create space for the exhaust. This is nicely outlined in the 1969 AIM manual a strong recommendation that you get.
These modifications are all under the rocker panel covers. So technically these modifications would not be visible if you wanted to remove the exhaust later.
Sorry I just deleted a bunch of photos related to this. I am sure someone will be along shortly to ad to this.
The “skirts” you are referring to are the rocker panels. In 1969, the only year the GM sidepipes were available, the rockers were removed. On a ‘73 with hooker sidepipes, Im guessing you would not be able to use the stock 70-up rockers. I think Ive seen people cut them up, and they werent pretty.
The other big thing to consider is you will be leaving gaping holes in the rear valance and 1/4 panel when you remove the mufflers. You have 3 choices: 1. Leave them alone (horrible looking) 2. Use a “filler panel” thats designed to plug the hole and clean things up… this is better than not doing anything and probably best as you are going to have a very modified look with the Hookers anyway, so you wont be trying for a stock look. Its also very reversible.
The 3rd option isnt even an option now that I think of it. Adding GM pipes to a ‘69 causes people to do the filler bodywork on the 1/4, and add a sidepipe original valance to the back for a stock look. You dont have that option for a ‘73 as there was not stock rear valance other then the one with the exhaust cutouts.
So, look for a filler panel. This is the area Im talking about:
You are right. The rocker moldings need to be trimmed depending on how tight the particular set fits your car. It is not a brand specific issue as you can have a problem with any of the manufacturers. You are wise to scrounge up a spare set of rocker panel moldings before installing the side pipes if you intend to keep your originals pristine.
Black headers need to be coated to slow the rust. Chrome will rust out faster than you want depending on how much and type of driving. Stainless steel will last the longest but it may need polishing once in a while especially where the pipes come out from under the car where they will turn a gold color. You can buy them ceramic coated but the finish will change over time. Dougs Headers are thicker steel as compared to Hookers. Your call.
STS inserts are popular but I like the Classic Chambered Vette Packs better personally. The sound is closer to what I grew up with as a kid. I loved hearing my Dad coming home from more than a block away. Very unique ground pounding rumble. NOTHING else sounds like real side pipes.
I've had both Doug's and Hookers. Neither one was a simple bolt on. One didn't fit quite right on one side and one didn't quite fit on the other side. There are probably some dimensional differences in either one, and probably differences in different cars.
So, long story short, it will probably be a trial and error fitting. I did have to trim the molding under the doors, but not the fenders.
most cars i see with aftermarket header side pipes are put on right over the rocker trim. including my 75. and i think it looks better than if the trim were removed. now, side pipes. they make the car louder and will burn your woman's legs. if you have a good functional orig exhaust, i would look at other places on the car to spend money and time.
Last edited by derekderek; Jun 26, 2021 at 02:11 PM.
The Rockers need to be notched for the brackets. My 71 came with the Hooker set, later I bought a pair of new rocker panels ($265), but I never installed them. If you look at my car I just used some Chassis Black paint and that’s it.
PS, there is a way to modify the Hooker brackets so you don’t have to cut the rockers. Just have to see a job done already.
Side pipes can look good from the outside. I wish they performed as well as the standard exhaust. But, if the 'look' is what you are after, only side pipes will do it.
They also have shields to put over the side pipes. They work great and the add a little something. You can practically put your tongue on them (if you want) and you won’t get burned.
My dad had a 74 with side pipes, burned a bunch of legs since folks are not used to getting in/out and having to step over hot a$$ pipes. If you plan on picking up people/etc and have a bunch of folks in/out of the car, don't do it...
Modifications to add side pipes?
