First off I have no idea if the exhaust I have is factory or not as I got the car used like many of us did.

My car is a 1987 Trans-AM 305TPI A4. I have dual exhaust outlets on the car. The exhaust is single pipe all the way from the headers to the muffler. The pipe looks to be about 3 inches in diameter. I would also like to note that the exhaust looks to new to be factory. There isn't the normal discoloration or any rust on it. It's clean compared to the rest of the underside of the car. I don't have any rust on the car at all. I just thought I would mention it.

Is there a way I can find out what brand of exhaust it is?
Does this sound like a factory setup? I have no one to compare cars with.
I have no idea what a stock 87TA would sound like. I think it's a little loud for factory exhaust. I would post pics but I have no way to really get under the car as my head is to big to fit under there and I have no ramps to drive onto. I also lack a digital camera to take pictures with.

I of course want to begin modding my car now that I have all of it's major issues worked out. But I am not sure I need the catback. I wouldn't want to replace it if it's already been done.

I also have no list of RPO's for the car. There is no real local track I can take the car to. So times are hard to get. The car feels to powerful for a stock 305TPI. Especially with the peanut cam I should have. Any insight into my situation would be appreciated.

Oh I forgot to mention. The tubing is definatley Mandrel bent. It is not crushed anywhere. I don't know if our cars had crushed tubing like a lot of cars do.

 

If its 3" its definately not stock. And I believe that stock would have the "crinkles" and not be mandrel bent. So I would say that you have an aftermarket system on it. And if you get under the car someday the muffler should have some type of marking on it as to what brand it is.

 

i would try to get under there with my arm or something and check to make sure it is 3" all the way back and then see what size the cat is. if it is all 3" then all you really need is headers and (IMO) ditch the cat for straight piping. then you would be done with exhaust mods...

 

I did get under there and check. I saw 3" pipe all the way back. 3 inch off of the CAT. Although I would love to get rid of that useless piece of crap. Since CAT's serve no real puprpose IMO. Due to Texas emissions laws I have to keep it.

 

I have what looks like a 3 inch I pipe (mandrel bent) and a flowmaster muffler with 3 inch inlet and 2.5 dual outlet. However the tailpipes are not mandrel bent. They have the stock design with that downward bend at the end. Anyone think if I change the muffler to 3 inch outlets and get 3 inch mandrel bent tailpipes, I would get any gains? I will be installing Edelbrock headers also and getting Hi flow CATs (I've considered removing or gutting them but seems like a lot of ppl are having problems with code 32 once they do this). Thanks.

 

im guessing you are in a city a little larger then mine then.....

 

i dont think you will see a gain at all. just to let you know i drove my car for a long time with no cat, but i dont own every 3rd gen in the nation so i cant speak for everybody

 

Yeah. I live in Dallas.

 

Mine have the 2.5 outlets. They also have the downward bend. They most certainly are Mandrel Bent however.