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Can be done. 426 guys make 900 -1000 with stock heads.

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Can be done. 426 guys make 900 -1000 with stock heads. Are Preddys better than S/S hemi heads?

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Can be done. 426 guys make 900 -1000 with stock heads. Are Preddys better than S/S hemi heads?

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They're about the same at around 480 cfm. But SS/AH heads need to retain stock valve angles and valve sizes!

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Can be done. 426 guys make 900 -1000 with stock heads. Are Preddys better than S/S hemi heads?

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They're about the same at around 480 cfm. But SS/AH heads need to retain stock valve angles and valve sizes!

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Then there's the small chambered Stage V Millennium Hemi heads that will flow 530

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Fred, do you recall what the 383 hemi P/S guys were making back in the day?

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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-

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Not enough CI for predator heads IMO. Fully ported B1's and spin it to 9500. Ask Bob Mazzollini, he did it.

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No offense to Bob Mazzollini, but he either doesn't run his car hard or he just doesn't make competitive power because when it comes to SS/AS, there's two other mopar guys that own that class that I could look to for help. One is the record holder and the other is the former record holder(Wes Lepold Jr and George Vignogna Jr. Both run SBM around 390's though.

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you cannot use a predator head,, and you cannot use a millenium head or any stage v head for that matter

if you want to run ss/am, or a/sma,, you need to run parts with numbers from mopar

a/sm and ss/am stuff that are fast are small blocks,, but i dont think you can get there with a small block without alot of money,,, the p-5 hemi is dead since there are no "new" available head castings

your best bet is to get a hemi 99 and destroke it some,, run it like that then build a new one with a small bore,, and build a 420 inch motor or so

if youre serious about this i may build one over fall/winter,, i can share ideas with you if you are doing one too

lloyd wofford has a b/sma stratus that has a patterson 358 p-5 hemi in it,, it make 950 or so and runs about .45 under,,, since there are no parts available to build a "better" motor,, there are thoughts to build a hemi 99 around 400 inches for it,, and move to a/sma

jeff

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you cannot use a predator head,, and you cannot use a millenium head or any stage v head for that matter

if you want to run ss/am, or a/sma,, you need to run parts with numbers from mopar

a/sm and ss/am stuff that are fast are small blocks,, but i dont think you can get there with a small block without alot of money,,, the p-5 hemi is dead since there are no "new" available head castings

your best bet is to get a hemi 99 and destroke it some,, run it like that then build a new one with a small bore,, and build a 420 inch motor or so

if youre serious about this i may build one over fall/winter,, i can share ideas with you if you are doing one too

lloyd wofford has a b/sma stratus that has a patterson 358 p-5 hemi in it,, it make 950 or so and runs about .45 under,,, since there are no parts available to build a "better" motor,, there are thoughts to build a hemi 99 around 400 inches for it,, and move to a/sma

jeff

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you cannot use a predator head,, and you cannot use a millenium head or any stage v head for that matter

if you want to run ss/am, or a/sma,, you need to run parts with numbers from mopar

a/sm and ss/am stuff that are fast are small blocks,, but i dont think you can get there with a small block without alot of money,,, the p-5 hemi is dead since there are no "new" available head castings

your best bet is to get a hemi 99 and destroke it some,, run it like that then build a new one with a small bore,, and build a 420 inch motor or so

if youre serious about this i may build one over fall/winter,, i can share ideas with you if you are doing one too

lloyd wofford has a b/sma stratus that has a patterson 358 p-5 hemi in it,, it make 950 or so and runs about .45 under,,, since there are no parts available to build a "better" motor,, there are thoughts to build a hemi 99 around 400 inches for it,, and move to a/sma

jeff

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Jeff, MBE has ads for P-5 stuff on their site. Maybe the castings are from down-under.

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