Yup. My brother's got a Fairlane with a 552" BBF. So we're kinda on the same page. There's a lot to building a BBF compared to a SBF. He found out that the front oil galley plugs are an odd size. If you put in a regular 3/8 NPT plug, it blocks the intersecting passage and restricts oil flow-and tears up the bearings. That was problem #1. Fixed, now the thrust it eat up. Back together today, but using a hat injector on meth. It was running 6.30 consistently on a gas pro systems carb, and then he tried an E85 Pro Systems 4500 specifically built for this deal, went 6.28 best and honestly was all over the place depending on weather, etc. Even different gas stations. Screw the E85 crap. Went to methanol, same price, actually a little cheaper and it's consistently pure methanol unless you leave the drum open sitting out in the rain. With the hat and ram on methanol, I'm expecting to see 5.90's and consistently. SCJ Aluminum heads, and this is with a thrown together home-built C6 with nothing special in it other than a basic rebuild.
Powerglide goes in probably later this year. I'm figuring another .3 improvement or thereabouts, depending on whether or not he cheaps out on the converter.
Keep in mind that is at 3580 lbs.
They'll make some power but they have to in order to justify the weight "penalty".
What is funny, as mentioned, is that the big block chevy guys are pretty maxed out at 496". I've heard of some 509's with a 454 block but not often. I don't know on the tall deck 427" blocks but they weren't that easy to find. So if they want a 565 or whatever, they gotta ante' up to an aftermarket block. A bone stock D9 BBF block will go 574" if you want to push it, to be safe and reliable, 557". They may even go 582, I have heard of it but never seen it in person. Probably a D0VE-A block if I had to guess.
Good to see another BBF on the board. I'm staying with a SBF, light, small, makes more than enough for me. I'm only at 5.80's in the 1/8 with mine which is all I need. The street car will be a stock block 427" and the other street car is a 2.3, all 105 mad horses of it!
WTT my '92 GT for a nice clean '91-'93 2.3/T5 hatch or coupe.