Uh oh, $#*!, not what I thought it was....

[NSTG8R]

I had a HVLA that just wouldn't stop tapping, so I sent a spare set in to get refurbed and thought I'd just swap them out and be done with it. I got the cams out (only after crafting some special tools to access some ridiculously hard to get to valve cover bolts), pulled the HVLA's, and that's when I saw the real problem. Apparently, one of the sleeves that the HVLA's run in has slid inward all the way to the head casting preventing oil from reaching the oil port on the HVLA...result, tapping. I do have a spare set of used heads that look pretty good. My question is, since I'm already down to a bare head on the drivers side, is it "possible" to remove/replace a SVX head while the engine is still in the car. I really don't have the room or hoist to pull the engine, but I don't want to get halfway into it then realize it's impossible due to the head bolts being to long and hitting the frame before they're completely out of the block. Anyone ever done this? Inquiring minds want to know, and 'any' input would be greatly appreciated. I need to get it done before the weather gets to cold out here.