Yeah, the 68-71 340 engines had the forged cranks, beefier forged
rods, forged pistons too. But in 72 they really tuned them down...
cast internals and a set of heads that dropped it from 10:1
compression down to 8:1.
What I did was take the 72 block, use the stock cast crank (good for
about 600hp) and went with some eagle i-beams, decent KB pistons and
magnum heads to get the compression back up to 10.1.
It's not really made to be a big powerplant, but enough to make things
interesting. ;)
Gary
On Sun, Feb 28, 2010 at 12:57 PM, Ray Block <BPracing@wowway.com> wrote:
>
>> -----Original Message-----
>> From: Gary Hedlin
>>
>> I'm not absolutely 100% on it, but I thought I read somewhere that
>> the 318's and 360's were internally balanced and the 340 was
>> externally. But maybe it's a year thing since mine was a 72 with the
>> cast crank and 318 rods.
>
> Gary, it can be found on the web but the 273/318/340 engines shared the same
> stroke. The cranks and rods are the same dimensions although I've read the
> 340 parts were somewhat sturdier. I can't confirm there was any difference.
> The early (60's-70's) engines used forged cranks. Later ones may have used
> cast cranks. (Ma Mopar cost savings ya know) Since my magnum 318 is
> internally balanced I'd have to think that at least all 318's have always
> been that way.
>
> The 360 arrived on the scene in 1971 and it's crank uses larger mains than
> the other engines but the same rods. 360's have always come from the
> factory with cast cranks. By my experience and study, the 360 is the only
> Mopar small block to be externally balanced from the factory...but I don't
> claim to know everything about individual model year engines I haven't
> owned. ;)
>
> Ray
>
>
-- Gary Hedlin 98 Sport 3.9 (for now) 05 SLT 4.7 www.superdak.com--Many talk about those who died, but too few talk about those who survived... THANK A VET!
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