> -----Original Message-----
> From: Gary Hedlin
>
> 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
Sounds like a good build, Gary! I knew the compression was dropped in '72,
and the exhaust manifolds were different than the earlier 340's (especially
the passenger side...big change). I was fairly sure of the cast crank
changeover as well. However, the '72's also came equipped with a
Thermoquad carb which somewhat made up for the compression loss. At high
rpm it flowed a good bit better than the earlier Carter AVS carbs. I owned a
'70 340 Duster at the time and picked up some good performance with the '72
intake manifold and carb! Yes I'm old...and was buying NEW cars back in
the 60's. :) Keep us posted on your build.
Ray
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