I wonder if it would be possible to run a GN style aluminum head in a TTA if you notched and boxed in the frame rail where the downpipe crosses between the header and framerail? I'm sure you could notch the rail and add at least 1" of clearance as long as the quality of the "boxing" was good. I just don't know how much wider the GN head and header is. My car currently has a 3" downpipe, but there is probably 1/4" clearance MAYBE 3/8", so I already know the issue of having very little room to work with on these cars. I'm just thinking out loud, and I know there have been some guys (Grumpy, maybe?) that have dropped GN style engines down into a TTA. Was there even CLOSE to enough room for a dowpipe going between the header and frame rail?