Re: Sport Truck Jan99

From: Jon Steiger (stei0302@cs.fredonia.edu)
Date: Wed Dec 23 1998 - 18:06:36 EST


At 12:34 PM 12/23/98 -0800, you wrote:
>Eric says:
>>got that too! Why is Terry runnin new 5.2 Magnum heads on a 71 340 block?
>>That doesn't make sense to me! maybe I'm wrong but arent those pre-emission
>>340 heads awesome? I've raced 340 dusters and what not before and those
>>things are smokin' hot! Why put newer 318 heads on it? Hmmm
>
>Actually, the Magnum heads are some of the best breathing heads Chrysler has
>ever made. I think the W5 heads are derived from the Magnum combustion
>chamber design, but for bigger valves and greater valve lift.
>
>I didnīt know the new heads would bolt up to the older blocks... I thought
>there-
>were a few bolts in different places.

  They don't... That's just one example of the many custom items on
Terry's Dak. :-)

>
>Anyone know whether thereīs enough wall thickness in a 318 block to bore out
>to a 340? Or is it better to start with a 360 block?
>
>Jim
>

  Hey, good timing, Jim! :-) Someone asked that same question in the latest
Mopar Performance News. Basically, the guy quoted an article in Mopar Muscle
that said the 5.2L Magnum had a 4" bore. The 340 has a 4.040 bore, so the guy
was asking if he could overbore his 318 and get a 340. Here is Mopar
Performance's
response:

    We have not seen the article you mention but can assume there are
    a few mistakes involved. First of all the standard bore for the
    5.2 Magnum is 3.910" not 4.000" (the 5.9 Magnum is 4.000"). By
    now you've figured out it would take an overbore of .130" to get
    to the 340 standard bore of 4.040". Obviously this is way too much
    for the 5.2 Magnum block which has a maximum overbore of .040".

   So, no, there isn't enough thickness to get to 340. I seem to recall
hearing that several people have stroked the motor to get a 340 though.

                                               -Jon-

  .--- stei0302@cs.fredonia.edu ------------------------------------.
  | Affiliations: DoD, EAA, MP Race Team, NMA, SPA, USUA. RP-SEL |
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