Thread: Big Block Dilemma

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I'm checking on a BB for my malibu and trying to find out if it's legit as stated by the seller. Guy says it's a mid 90s 454 HO 425 hp GM Performance crate motor. Here's what I have: block casting #12550313 (gen V?) no provision for mech fuel pump, no clutch boss, has roller cam, oval port heads. Engine assembly is new and complete intake to pan. No flex plate or water pump. I've searched the 'net with not much luck. Any help would be appreciated. Thanks

I have futher: head casting number 10141279, I think these are oval port closed chamber (100cc) vortec 7400 heads. Camshaft AC2416216 is laser etched near the first lobe near the front of the motor, pushrod guide plates are stamped RADAR, Crank casting number 10114188 (cast). It does have the roller lifter spider plate, hydraulic roller lifters, 4 bolt mains, the block has a tag marked "manuafactured for GM part number 12491330 date 1-2006, not much luck finding that # on the net. It has a six bolt cast aluminum timing cover. Any help would be great, thanks

More yet: I found and obscure site when checking for the part # 12491330 (like page 55 on a google search) it was in Russian or something. That part number, 12491330, shows a 454 replacement crate motor, not much info at all. Does anyone know if I can use my dial indicator and height gauge to check the cam lift while the cam is in? I've done it before with the intake off and used a solid lifter, but never from the bottom on an assembled hyd roller long block.

well the block should be a mark 5 with a fuel pump boss with that number but ?? i look the number up and said that number did have a fuel pump boss ? they could be wrong .all the older mark 5 did not come with a roller cams or fuel pump boss s from gm .some of the mark 6 did .i am not sure if your block has the towers casted in the valley for the roller hold down plate for the GM( spider) if so then its a mark 6 blocks other then this there about the same block 5/6all the 454 425 i have seen did come with rec port iron heads .i do not think the heads are right. GM did not use there iron oval ports sounds like someone may have put them on. if not rect port .if so older mark 4 heads they will not seal up on the new deck and will leak .now if there GM 502 alum O port 12363390heads i think they did rate that at 425 hp. get the head numbers take a valve cover off if needed to get casting numbers

12550313...454.......91-up...4-bolt, Gen.V crate motor, Gen. VI 4.25" bare block, fuel pump boss

Kitz

thanks for the info, I can check the head casting numbers in a couple days. Not sure what you mean by the "spider" hold down plate for roller lifters but if it is obvious, there is a second motor for sale (identical) without the intake. I can check for that also. I'm concerned about the head leak issue. I'll keep you posted.

spider ZZ502 ..............

boris the spider by the who?????????????

the pic is great. The spider is obvious. I'll let you guys know what i find out in a couple days. Thanks again....

I have futher: head casting number 10141279, I think these are oval port closed chamber (100cc) vortec 7400 heads. Camshaft AC2416216 is laser etched near the first lobe near the front of the motor, pushrod guide plates are stamped RADAR, Crank casting number 10114188 (cast). It does have the roller lifter spider plate, hydraulic roller lifters, 4 bolt mains, the block has a tag marked "manuafactured for GM part number 12491330 date 1-2006, not much luck finding that # on the net. It has a six bolt cast aluminum timing cover. Any help would be great, thanks