master
Joined: Jul 2010
Posts: 3,502
SOUTH JERSEY
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Quote:
Fred, do you recall what the 383 hemi P/S guys were making back in the day?
DAVE HEITZ just did one last year for one of Reed's cars. Dave built the roriginal record holder for John Hagen . I beieve just over 800 HP
I don't remeber where I got this info but it's informative Quote:
Back before NHRA had a policy of all Pro Stockers being 500 CI / 2350 pounds, they used to factor different engine at varying weight-to-cubic inch ratios in that class, assigning whatever figure they thought would make for competitive racing. Because of heavy pistons and difficulty in getting the requisite 15:1 compression, Hemi's had fallen out of favor. Some people tried de-stroking a 426 to 383 cubes, but it didn't work well, exacerbating the compression ratio problem, as well.
One of my closest friends at that time (1981) was a racer who looked at the problem and decided to attempt to add the 426 Hemi heads to a 383 block, The 383 was lighter, had a shorter stroke, and a better rod angle (in his opinion), using shorter, lighter connecting rods.
He eventually built 10 of these blocks, which were 400 CI blocks (he said the casting cores for the 400's had more meat in the cylinder walls, determined after sonic testing a bunch of 383/400 specimens.)
One of these blocks ended up in the late John Hagen's Plymouth Arrow Pro Stocker and without any factory help, nor more than a few months development time, set the mph record for Pro Stock. The car also was runner-up to Lee Shepard at the Pomona World Finals that year, the last race before the 500-inch/2350-pounds for everyone rule went into effect the following year.
How fast might this combination have been given an ounce of factory help, or a couple of year's development time???? VERY fast, I'd say.
The modifications to the block were covered in detail in an article I wrote for Super Stock and Drag Illustrated in the June 1980 issue. There are lots of photos to document the addition of the row of hold-down bosses to the valley area, and the machine-work and welding in of half-tubes to enable the push rods to lay down the required angle to connect with the exhaust valve rocker arm pushrod sockets.
It was a job for a welder who could weld cast iron to steel and not have it crack at the seam, due to thermal expansion/contraction.
One of these engines went into an A/Dragster and promptly grabbed the record for that class (a Canadian, named Wally Dyck.)
Some were sold to high-line Mopar guys like Butch Leal; I think Dick Landy may have ended up with one. I know that Charlie put a 440 crank in one and ran nitrous to it in a Volare he built for IHRA Pro Stock.
I also wrote a follow-up article about the accomplishments of that engine for Chrysler Power magazine a couple of years back, but I can't remember which issue, offhand.
At any rate, the whole deal was about specific output, and the 383 has it all over the 426 and 440 when it comes to that, because it's moving a smaller amount of air through the same (Hemi) valves and ports, enjoying less friction, a shorter stroke, higher redline, and less reciprocating weight along the way.
Charlie did a lot of research on welding techniques before he came up with a successful rod and heat combination in order to make welds on the block that didn't crack in competition, but he finally got it.
I think he was selling these things for a thousand dollars apiece; a pittance, considering all the work involved.
I think he also added an oil return line from the heads to the pan, as the Hemi had no oil return that would work with the low-
home of the Sox and Martin Hemi Duster
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