Summit Racing part number HOK-2055-1HKR, sells for $720:

http://www.summitracing.com/parts/ho...1hkr/overview/

They will bolt up to any 3rd gen with single cat exhaust. Summit's site says it's for '88-'90 but that's because of the air tubes I believe, and the air tubes have been cut off of the headers and the holes welded shut.

The headers are used and the y-pipe is brand new. Reason for that is my dad bought the whole kit and was going to replace what was on his car but he ended up just swapping the headers out with the new ones and left his old y-pipe on the car.

$550 shipped in the continental 48 states, can get shipping quotes for anywhere else.

Is the outlet on the y-pipe 2.5 or 3"? I can't seem to figure out which based on what summit's page says or Hooker's (Holley's).

It is 3" at the outlet

I just re-read, you said he swapped them out for a new set, is there something wrong with these?

My dad had spent the better part of the last 6 months trying to track down a problem with his car running lean on one bank on his LT1 - one o2 sensor was giving him a reading that was way off from the other side. He tried changing the intake gasket, swapping the headers out, among numerous other things. Even after all of that stuff the A/F ratio was unchanged. He just took it back to the tuner about a week ago and after some tweaking it is finally running properly.

So to answer your question, no there is nothing wrong with them to my knowledge, given that the A/F ratio was the same before and after swapping them out. Obviously the AIR tubes have been cut off and welded shut, so that would affect the emissions testing depending on what state you live in.

I have PayPal, so if you would like to buy them, send me a PM and I'll send you the address.

WRT to your dad's problem, I don't know if he figured it out but my top 3 contenders (I would have never gotten to headers unless they were OBVIOUSLY leaking):
- the FPR has a leaking diaphragm, fuel is leaking into the vacuum side and dumping into that side of the manifold
- a bad O2 sensor
- a bad injector(s) (really doesn't happen as often as people seem to think it does)

He checked the o2 sensors and injectors, didn't try fpr. I don't even recall how the LT1's are setup, might have to look at that.

Sold.