Originally Posted by Filmjay
Based on that 496 buildup, what would you start with for a short block?
I don't have swap meets of anything of the like nearby that I can just go pick up an old hot rod motor.
To follow the Car Craft build, you'd start with a Mark IV block with 4-bolt mains. Most of the 70-90 454 Mark IV's could be found with either 2-bolt or 4-bolt mains. Here are some casting numbers.
3999289 71-79 454 (the block used in the article)
361959 73-90 454
3963512 70-76 454
10051107 454 Bowtie block. Siamezed bores, can be safely bored to 4.500". With a stock stroke 454 crank in this 4.500 block, displacement is 509 cu. in.
There seems to be a problem with using Mark IV heads such as the AFR's or any other Mark IV head on a later Gen V block. Here's a blurb from Chevrolet....
"Important Technical Note:
Use of the adjustable valvetrain Mark IV cylinder head is not recommended with the new “Gen V engine,” except with Bow Tie racing blocks and all Gen VI with six-bolt composite front covers.
Changes in the configuration of the “Gen V’s” coolant transfer passages allows coolant to seep into the lifter valley when the Mark IV head is used. Mark IV camshafts, water pumps, intake manifold, distributor and clutch housings can be used with the new “Gen V” engines. “Gen VI” 454 crate engines and bare block P/N 12550307 are the only “Gen VI” blocks that have machined fuel pump boss."