Does anyone know if the stock throttlebody on an L27 can be replaced with one from an L67, (assuming it is larger) for a performance gain. Also does anyone make headers that will work on an L27?

Your throttle body is the same throttle plate diameter as a 92/93 L67. No other differences.

Nobody makes headers. You can port your own EM'*. If this is your interest, and you know a good welder, ask for details. It'* too involved for me to go into for a simple question.

There are some minor changes you can make to your TB to make it perform better, but you must have an EndMill and a dremel tool.

Unfortunately i don't have an endmill. I was just under the impression that the L67'* was bigger. Just trying to squeeze some more hp out of it without getting into the motor too much.

The 92/93 L67 is not bigger. The 94/95 L67 and the 96+ are bigger.

If you're interested in either a ported throttle body or ported exhaust manifolds, search on those terms with me as the author. Or start here:

http://www.bonnevilleclub.com/forum/...ic.php?t=36232

And for the TB:
http://www.bonnevilleclub.com/forum/...ic.php?t=39164
Forget the part about removing the MAF support. That didn't work out too well. But you can shave the throttle shaft and countersink for flat head screws to increase WOT flow and give it a bit more snap to WOT.