I've been looking on the net for a straight answer here and cant find a damn thing. Another of my cars has a weak engine in it and I've been planning on building a 434 out of a factory block, but now I'm considering putting it together as a 406 TPI for my TA and using this block I recently stumbled on to build my 434. If I gotta buy a block, might as well get a good one.

Problem is the info is different on every site. Different websites say different things for weight, rear seal, maximum bore (biggest concern) and max stroke. I tried emails and nobody seems to know.

Apparently the max bore is either 4.090" or 4.155". I also read that it can go 4.185 since it has siamesed bores, but there is no info on the bore thicknesses at these sizes for me to go by. I cant even get an answer on if it accepts OEM roller lifters or not, but IF the pics are right, it does and has a 1 piece rear main seal.

I'd like to toss that LT1 FI conversion hardware I have on one of these if it'll work to my needs. I plan on using a 4" crank, 6" rods, CNC ported Brodix Track 1 heads, custom grind small base circle cam, ported single plane, canton pan, and keep it hydraulic roller in a near factory arrangement. Goal here is a streetable 434ci motor making at least 600rwhp that can take some nitrous. Cubes are the shizzle =) Anybody know a reliable source I can get this info? $1395 is a great price for a bowtie. By the time I ship it and bore it I'll have $1700 in it and it'll be ready to assemble. That's not counting if one of the parts guys on here can beat that price. I'd happily drive to pick it up somewhere.

I find it hard to believe, all that extra weight and cost over a factory block for an extra mere .030 bore, really.

 

Well at least it looks as if the block is a one piece rear main, siamesed, oem roller cam equipped block that goes 4.155". I dont know for sure on the bore yet because I keep getting two different answers. Looks as if GM rates this block to 4.090 to keep people looking at the more expensive engine blocks. This makes sense to me, because if its a siamesed heavier duty 'aftermarket' block, I dont see why it wouldnt go 400 sized.

Im going to make some calls tomorrow to try to confirm this. If anybody has some input that would be GREAT. The one question I have for you guys, that I can tell from here, is if there will be any interference issues between the block and the A/C compressor, there the fuel pump blockoff would be. Can somebody take a picture of this for me? Trying to decide if I have to get the fuel pump pushrod hole blocked off and grind down the mounting boss.