LT1 Headers Question? 95TA (Please help)

[rediculous95t/a]

I have a set of headers and y-pipe that I bought used, they have no labels, stamps, numbers, brand, no way to identify who made them. They look like Mac mid length headers with y-pipe, 3inch y-pipe outlet to the cat. I bought them off a guy on craigslist who says they were removed from a 1994 Pontiac Trans Am with LT1 motor.
My problem is that the headers do not have D-port connections to the heads, they are square or retangular in shape. They are old headers, I have sandblasted them and had them ceramic coated. They look real nice and it appears they would seal against the heads without leak. I bought felpro 1406 gaskets for LT1 and they are also D-port shaped.
It looks like the D-ports are bigger than the ports on the headers, so there may be some restriction. I am not sure if i should use them. Any thought's anyone?

[1sickta]

Put the gasket on the flange and snap a pic. Might be able to open it up a bit.

[zooguy]

Put the gasket on the flange and snap a pic. Might be able to open it up a bit.
smart

[Injuneer]

What is the diameter of the primary tubes?

Sometimes they will put a bead of weld material around the holes in the header flanges, to create an "anti-reversion" baffle, and prevent backflow into the exhaust ports at low RPM. I had a set of JBA 1-5/8" step headers, that had 1-1/2" diameter for the first couple inches of the primaries, then stepped up to 1-5/8". They had the weld bead for anti-reversion. Somehow, I don't think that was really necessary when they already had the 1-1/2" step. Bottom line - the JBA's made good low end torque, but they really strangled the engine above 5,000 RPM.

Measure the primaries, see if there is a "step", and post a pic of the headers..... might be able to identify them. Do they have EGR and AIR connections?

[rediculous95t/a]

Here are some pic's2397723978239792398023981

[rediculous95t/a]

The Fel-Pro 1406 gaskets in the picture are designed to fit Brodix Track 1 cylinder heads, I am thinking the D-ports may be larger for those heads. I believe they are 1-5/8 primary's on the headers. The smog hook-ups are were they are supposed to be for LT1 Headers, but the EGR hook up is a little higher than usual.

[jlo]

I had a set of MAC headers back in the day and they had the D-ports on the headers. The EGR pipe that goes in back of the intake also didn't go straight up like the one in your pic.

[rediculous95t/a]

I am going to assume that these headers are trash. I can't sell them if I don't know the brand or why they dont have D-ports.

[jlo]

Do they have a part number or any identification on them? check around the flanges.

[rediculous95t/a]

I spent hours trying to figure out why these headers do not have d-port connections on them and why the egr hook up is raised so high. I have come to the conclusion that these headers are for an L99 4.3l V8 engine that came in the impala and caprice model cars. The L99 motors looked like the LT1 but is a smaller displacement with cast iron heads and no D ports on the heads and also explains the raised egr valve connection. Anyones input on my findings would be greatly appreciated.

[93z28de]

thay look to be of lsp or maybe mac headers for a 82-92 fbody lets see the y pipe if you have the flanges look like a mac header but the bends make me think there for a 3 gen and not a 4th gen i could be wrong tho ....just trying to help

[rediculous95t/a]

I traded the headers and y-pipe today for a fully ported LT1 intake manifold. The intake will come in handy for my LE2 Heads and cam build. Meanwhile I will just save for a good pair of long tube headers. Thanks all for your input and support. :D