More fitting and adjusting today. I checked how much I had move the engine backwards, and it looks like it was 3/8" of an inch.
Here's the issue with the passenger side valve cover and head:
I jacked up the trans pan, but it didn't take long until the engine/trans caught on something else. However, that did give me about 1/8" clearance between the driver's header and the frame.
I decided next to get the power steering pump in, so I could check out if a smaller pulley would do the trick. Space is so tight that I had to remove the front accessory bracket, bolt the pump on, then reinstall the bracket. I tried the S10 pump first, since it has a smaller reservoir, and I figure I could just T the return line for hydroboost, but it was clocked in such a way that it will not fit unless I cut away some of the bracket. I may still do that. The Sierra's pump went in, and the bracket was bolted up. It's a bit of a tight fit.
To the right, you can see the hydroboost return fitting is actually rubbing against the return line for the steering box. I don't think there is anything I can do about this if I keep this pump, other than just keep an eye on it, and replace the lines if they get worn enough to start leaking.
The stock pulley definitely will not fit, but that looks like considerably less than .75" interference, so a 1.5" diameter smaller pulley should work just fine.
The final fitting check that needed to be done was for the front of the engine versus the radiator fan. It was nice to have the core support back on, even if only for a few minutes.
Major success here, there is plenty of room, especially considering the SBC was right up against it, and did a little self-clearancing of the fan housing
With 7/8" of an inch up front, I decided to move the engine forward a smidge, and got it about 3/16" forward, pretty much splitting the difference of where it started and how far back I'd pressed it. At this point, if the transmission is jacked up enough, the heater box clearance issues go away, but I still have a problem with the driver side header and frame. I think the transmission is getting caught on its upper cooler line, but with the truck on the ground, I just can't tell for sure.
I am a little concerned about the fuel lines potentially rubbing either the bellhousing or the cab floor, but I can just run them outside the frame, and over the brake booster if need be. I am tempted to grab a smaller booster from the junkyard, and not worry about getting hydroboost working from the get go, just to simplify things. If I do, I need to take a look at where the truck intake usually has a vacuum fitting, as mine does not have it.
I do have a different fitting concern now, too. I have no idea how crooked the engine is sitting. Shifting the angle could be enough to get rid of or create more fitment issues. The transmission crossmember really is the linchpin in all this. Plus, I need to have a little extra room to lift the back of the transmission, to get the driveshaft angle right, since the truck is lowered. I may have a solution, though. Summit advertises Holley's transmission crossmember as in stock, even though Holley apparently does not have any. If I do not get a relatively firm shipping date by Monday mooring, I think I am going to cancel my order for the GForce piece, and order the Holley one, and hope it works fine with the engine mounts I've selected.
Right now, I'm kind of debating with myself over whether to pull and modify the heater box this weekend, or let it ride, and see if it all will fit. I am also finding myself wishing I could stumble on a clean GMT400 RCSB roller for a great price, and just put the drivetrain in it, instead.