Also check recycler.com and craigslist.
Depending on your abilities, you might want to source the shortblock separate from the heads.
As a side question...are you running a 2 speed auto in that? You may want to put a 3 speed or 4 speed auto in first, if the engine is running well, and take your time and save while you are at it.
There are deals out there...it takes patience and determination. If I find a great deal on a 455, for, say $200 bucks, I'll let you know.
To clarify, I'll let you know there are great deals out there
Seriously, good luck. Also, check out the Long Beach swap meet. Pomona is not very good for Pontiac parts these days, and tends to have higher prices.
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How many of you have driven over 340?