3100/3400 exhaust maniolds on a 2.8?

[CorvetteBeretta]

Possible or pointless?

[Money pit Beretta]

It's a good upgrade for the 2.8L. They are much bigger and have better flow. The D ports block a little of the 2.8's ports, but that doesn't hurt. From what I know everything bolts up nice when it comes to the engine. As for the down pipe that is over to one side and will not bolt up to your exhaust.
The only thing you have to worry about is your coils and ICM. The front manny is not that much bigger, but still it would be closer to them.

[CorvetteBeretta]

Is it possible to grind out what blocks it

[Money pit Beretta]

I've heard there is no need to. You can have gaskets that are too small and block the ports some. That helps exhaust flow( you are just going to have to have some trust on that one). It has been tested by Ben at WOT-Tech and many others over the years.
If you feel the need you can grind the D out of the port. There is more than enough "meat" there. So there should be no worrys about cracking.

[CorvetteBeretta]

So couldn't I just use 3400 headers?

[1988GTU]

Possible yet pointless. Use the cash on a nitrous system for what headers will cost. Install would be easier as well over headers for a 2.8/3.1.

Id rather even consider a tgp mod to fit install over headers.

[CorvetteBeretta]

I'm going to use OEM 3400 ones and see what happens.