See this crappy out of focus photo? This was taken with my $20 USB endoscopic camera. It's right down the plug well of my #1 cylinder. What you see here, the blobby bit at 1 o'clock, is a dangling intake valve seat.
This could have been a lot worse. If it was the other bank, then the brake booster and master cylinder would have to come out. With this, it's just find TDC, pull the distributor, pull the water pump and inlet, pull the cam gear and camshaft, remove the head, totally replace the #1 intake valve assembly, and reassemble. Easy.
I need to track down a special tool to hold the cam while I remove the pulley gear and make a special tool to actually pull the cam. Around $60 for something that won't break, or $30 from Harbor Freight.
New seals. New head gasket. New timing belt. Probably new water pump while I'm at it. Machine shop to level the head, and grind & lap the valve. Then I'm stuck with the notion that I'm half-assing the job by just replacing one valve. Should I do all 12 valves? And if I'm doing that much work, why not pull the pistons and install new rings? That's on all 6. My compression is good, but you know, why not do a job that'll need to be done soon anyway? And I mean, look at that carbon buildup.
I could easily spend $3,000 on this. Which I don't have. Not even close. Just doing the one valve will probably be at least $300-500 though. Not to mention my hours involved (several GTV6 guys say the heads are damn near impossible to remove and could take up to 20 hours of gently prying, lifting, tapping and jiggling to break free).
I honestly think it might be easier and cheaper to just find a decently clean 12v motor and do a straight swap... and pray it's not a turd. Then keep my original motor in the shed and gradually rebuild it into something a little more badass. 164S cams, slightly bored, port and polish, headers, motronic injection, etc.