Ok, I have a 91 tpi car with the dual ypipe. I have a set of Edelbrock TES headers. I have the flanges for the headers ,but no ball collector (I think that is what they are called) LOL, Anyways, I went under the car today to look at the stock ypipe and the stock flanges look the same. What I am wondering is if the stock ypipe collectors will bolt on the edelbrock headers? or are the collectors on the stock manifolds too small? I was thinking about cutting the ypipe about six inches or so on each side below the stock exhaust manifolds, bolting the headers up to the heads and then getting the pieces that i cut re welded to the ypipe. Anyone know if the end of the stock ypipes that bolt to the stock exhaust manifolds will bolt up to the headers?

 

"dual y-pipe" is new to me...
-- A "y-pipe" joins the two collectors into a single exhaust pipe.
-- An "h-pipe" has the connector, but maintains genuine "dual" exhausts.

The debate rages between a sufficiently sized (2.5" -3") single set-up,
versus a true dual setup, usually less that 2.5" pipe diameter.
Since our f-bodies were designed for a transverse mount muffler, space
for true duals can be a bit of an issue, with ground clearance the biggest
obstacle.

If you have the collectors that mate to the headers, the intention is to
create the rest of the system behind it. Chances are slim that the stock
flanges will be compatible with the TES headers. And probably likely that
the TES flanges are considerably larger than the existing exhaust pipe.
So grafting it into the existing system will minimize the header gains.

Best bet is to prepare for upgrading (i.e. larger diameter) the entire system,
including a hi-flow cat.

good-luck

 

my car has dual 2.5 inch piping to about half the car, then it merges into the 3inch catback that i just put in there. from the research i've done that dual catalytic converter setup made slightly more power,which is why i didn't trash that portion of it.