Hi all,

/6 Dan said: "I used to have a very detailed report on the matter from the '60-'61 timeframe when the NASCAR Valiants were being campaigned..."

As Dan also said it would maybe have to float up to the top of his pile..,MMy pile looks like one of those TV shows where some group goes in and cleans up the house, at least in the corner with my last 50 years of Mopar and hot rod magazines! But my interest had been stimulated by recently finding an nice hyperpak 225 1970 duster not far from my house. With AC yet and I had remembered a report on the hyperpak too.

Turns out it is in the July 1961 issue of Cars (The Automotive Magazine) in two articles, one by an anonymous author (maybe a mopar press release?) entitled "Hyper Pak" Your Slant; the other by T.C. Elle entitled
"Hyper-Pak" Spells Performance".

In the first article the first picture is the same "kit" picture Doc posted i this thread. The article has 19 pictures and instructions for each step in putting a hyper pak on your Lancer or Valiant. It is a report of work "a master mechanic of the old school" Alfred Momo did for Briggs Cunningham "millionaire sportsman". It suggests the aluminum block "now appearing" will be good with a hyper pak, and says the 170 turned 128.282 mph in 2.5 mile laps at the "new" Daytona speedway. It says the 170's got 150 HP at 5,000 rpm and the 225's got 196 HP at 5,200. The hyperpaks were supplied by Virgil Exner.

The second article is more of a test article of the 170....stock block, hyperpak, then hyperpak with a McCullough supercharger. The stock CR was 8.2:1 and the 170 with Hpak and blower had a CR of 8.6:1. Cars had an AFB 4bbl manifold, "hot"? cam, dual exhaust maniflold, tubular push rods and "special" springs. The blown car had a 3.91 and the other two had 3.55's. The cam made it lope and it was "not the most enjoyable" car to drive on the street.

Stock got 19.5 sec in the 1/4 at 69 mph, top speed of 96 mph. The Hpak car got 16.3 in the 1/4 at 83 mph, top speed of 113. The Hpak with blower got 14.7 in the 1/4 at 94 mph with the 3.91 with a top speed of 119mph. They also ran the Hpak and blower with a 3.55 and got 15 sec at 91 mph in the 1/4 and top speed of 115.

They also
"slightly milled"? the head of the blown engine and ran it at 6200 rpm with 0-60 in 7 seconds. Mellow. They describe it as feeling like a "Hot" 350 Chevy. The plain hyperpak on the 170 yielded 0-60 in 8.6 seconds.

I am assuming flat top pistons since they use a bone stock 170 except for the induction, for the most part and didn't report any other engine work. Not bad, for $2,800 new. Gas mileage was what we get now...14 with a blown hpak and 21 stock.

rock
'64d100

Rock, I have that magazine you're talking about -- but it's not the detailed report on the NASCAR Valiant Hyper Pak configuration that I have in mind, which is somewhere near the bottom of the heap

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

(Posted for Dusty Desks by Chuck)

The published data reporting that the 225 hyperpak compression ratio was 11.5:1 has to be incorrect. Logically, this can be deduced as follows: We know that the same high-compression piston was used on both 170 and 225 versions. So, since the total combustion chamber volume (including piston to deck height at the top of compression stroke) is greater on the 225 than the 170, and both engines have the same stock compression ratio, the increase in compression has to be less for the 225 than the 170, because the effect of the domed piston is less percentagewise on the 225. So, it has to be less than the 170 figure of 10.5:1. There is enough data here to figure out exactly what it is, if somebody wants to do the math.

Dusty Desks

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Chuck Rivers, Webmaster