Sometimes, history is created in the words and pictures of those who were there then. And, sometimes, it falls out a back door that was open then. So it is with what may be the earliest known 426 Hemi cylinder block, which is in the collection of Mopar enthusiast Jim Ludera.

Before we get in to how Jim found it, a little history behind this block and the 426 Hemi development program is in order.

In December of 1962, Chrysler boss Lynn Townsend approved the 426 Hemi engine program, with the goal of having a race-ready engine in time for the 1964 Daytona 500.

That didn’t leave much time for Willem Weertman, then Chrysler’s assistant chief engineer, and his crew in the labs at Highland Park. They proposed a hemispherical head for the RB block, and the new head was designed in March of 1963, with more new parts coming off the drafting boards that spring and summer.

The first complete 426 Hemi engines went on the test stands in Highland Park’s Building 135 late that fall. With the exhausts routed through pipes that led to outlets on the lab’s roof, the sound of Hemis at full song could be heard all over the city of Highland Park and nearby Detroit neighborhood--sand likely spooked some critters at the Detroit Zoo about five miles away.

On January 28, 1964, when that testing was simulating 500 miles of race conditions at Daytona, big problems appeared. Blocks cracked in the right-side cylinder bore walls and opposite the piston pin piers. As it was now about one week before the factory Dodge and Plymouth teams would roll into Daytona, something had to be done to stop the blocks from cracking--and fast!

Weertman and Larry Adams, who was in charge of race engine development, came up with a fix: Make the cylinder bores thicker. In turn, that meant the sand cores used at the foundry had to be filed down by hand to permit more iron to flow in to create the thicker bores. Weertman flew to Indy to work with Chrysler’s American Foundry Division in Indianapolis to put the fix into the next batch of blocks to be cast.

Once that next batch was cast, came another disaster. These had huge voids in them, which led to round-the-clock thrashes there and back in Highland Park. The cause was identified as too much residual moisture in the sand cores, solved by more thoroughly baking the cores before they were put in the core boxes to make the molds used to make the Hemi blocks.

24-hour work at Highland Park also identified another problem area: residual stress in the blocks, caused by the casting process. The metallurgists in the stress lab came up with a plan to relieve it by annealing the blocks once they’d cooled. They’d go into a furnace, heated to 1,200 degrees Fahrenheit, and then slowly cooled down to "bake out" the stresses in the block.

Those fixes came none too soonthe teams (including two-car teams from Petty, Ray Nichels, and Cotton Owens) were already at the "Big D," and they’d agreed among themselves not to run the Hemis they had flat out during early practices; that way they were not tipping their hands to the Blue Oval teams, who’d complained long and loud to NASCAR the year before when a Ray Fox-prepared Bow Tie 427-inch Mystery V-8 blew them away in practice, time trials, and one of the 100-mile qualifying races.

The first batch of good Hemi block castings was poured at American Foundry on February 3, 1964--the day before tech inspection at Daytona. From the foundry in Indy, they were trucked to the Trenton, Michigan, Engine Plant for machining, then to the engine lab at Highland Park for final assembly.