Looking to start a new project, a 454 stroker motor.  I have been told to find a 454 with the one piece main seal style blocks.  I call a local engine shop for the block and find that this information is apparently useless, they want a year/make/model it came in or engine block number.

Does anybody know what these engines came in?  Or does somebody have a better idea for the block?

thanks  

I'd find a new engine shop, or at least not let them do any engine work for you.  They are obviously in it for money and not for the love of engines. I would think a safe bet would be any 454 built in the 90's, later the more likely.  Sorry I don't have any specifics, I'm a Buick Guy.  

Ill tell ya all I can.I now have a 80'4 bolt main 454 Truck block.If you wanta wind tite with this thing get out ur wallet,first.My  block and reciprocating assembly is about $1,500-2,000.Back in the 70' chevelle day's it was called the LS6&LS7 454.Now mine is a two piece 4 bolt Gen4.Im not sure of the block mix at the foundry  on the 1piece Gen5 4 bolter,but the rating is for truck applications,and that is the category for my LS7,marine,truck,HD,etc.Now if you wanta get BFH outa ur BBC,Id go with a talldeck.They come in farm equipment as a rule.The talldeck block has a .040 takker deckheight,for longer rods hence lesser rod angle,hence better center of piston thrust or downloading as its been called.Bad thing bout'em is the're rare as are the parts-again,get out ur wallet.Intakes,rods,pushrods,all that special stuff.But a LS6or7 will handle well into the thousands for clydesdales on the track,with good machinework.I do agree 4 a diff.shop.they dont have a clue.My friend up here tought me a lot of what Ive just told you.Course hes bout 75 now.Still the BEST..!  

sounds like your looking for a vortec 8100 (496) to beef up. i'm not sure about the specifics, but i'm guessing wikipedia could help you get started...

here ya go.

The Vortec 8100 (RPO L18) is a V8 truck engine. It is a redesigned Chevrolet Big-Block engine and was introduced with the 2001 full-size pickup trucks. It retains the same bore centers as the old 7.4 L big-blocks, but stroke was upped by 9.4 mm to reach 8.1 L (496 in³) for a total of 107.95 mm bore and 111 mm stroke. It is an all-iron engine (block and heads) with two valves per cylinder. Power output ranges from 225 hp to 340 hp (168 kW to 254 kW) and torque from 350 ft·lbf to 455 ft·lbf (475 N·m to 617 N·m). Vortec 8100s are built in Tonawanda, New York. The Vortec 8100 is the engine used in the largest Uhaul, their 26' truck.  

The 8100 engine is considered a Gen VII motor, I'm pretty sure that nothing will interchange with previous engines. They are night and day different, no distributor, different head bolt pattern, different firing order, etc, etc...

Gen V and Gen VI engines had one piece rear-main seals. The Gen V ran from '91-96, the Gen VI afterwards until '01 and then finally the Gen VII from '01 to the present. I really don't see a problem with a Mk IV block though. If you're looking for a large bore block then you need a Gen V or VI "bowtie" block but if you want a conventional 489/496 then getting a early 454 may be easier to find and it may have some large oval port heads on it that could be rebuilt for a performance engine. If you find a one-piece rear main 454 it's going to have peanut-port heads that are awfully worthless for anything but a stock-rebuild.  

1996 and up Gen 6 Blocks are one piece seal, and as an added bonus, come set up with a roller cam.  You can either find them in crate motor form, or in a Suburban or Pickup.  The truck engines have good heads for torque, toss them if you want speed.  I am building one right now, will end up as a 489 most likely.  Good luck