I used to have, until 2 years ago, a '68 Impala with a 327. Car is gone, but
the engine will go into my '57. Mine was like the 327 from the Camaro in
the '56 in that it is a 250 horsepower version. Has a Q-jet, but low
compression heads. I seem to remember 8:5 or 8:75 to 1. I ran unleaded and
with the low compression, never had any pinging or detonation. Tried some
lead additives on occasion with no difference in performance. Had 43k when I
got it, put 50k more on it. Still ran great, pulls strong (dang, loved that
old powerglide!). Have a 700R4 to put behind it now. I have been told that
if I ever re-do the engine or heads to put in hardened seats and at the same
time go to bigger valves, 1.94's - 2.02's may not be needed for the street.
So maybe this may be something to consider too. The low compression 327's
have smaller valves, intake AND exhaust, than the other higher comp.
versions. Open it up and let it breathe when going to hardened seats.
Ed in Mich
'57 3100
----- Original Message -----
From: <Cameo3124@aol.com>
To: <oletrucks@autox.team.net>
Sent: Thursday, March 20, 2003 2:43 PM
Subject: Re: [oletrucks] Running unleaded
> 1972 and newer chevy small block heads had hardened seats for running
unleaded gas, unless the 327 you have is a hi compression engine you
shouldnt have any problem running unleaded gas, performance will slowly fall
away as the valve seat wear do to lack of lead lubrication .. you can buy in
some states lead gas additive that will enable you to run unleaded gas
without eventual valve damage,, but additives can be expensive over time. If
your engine is in pretty good shape and all you want to do is run unleaded
gas you may consider either buying a set of heads that are 72 or newer or
have yours reworked with new hardened seats,, check with your local machine
shop for pricing,, I just paid $180 to have a set of heads reworked with
out the added expense of the machine work, labor and cost of seats, I
imagine it would be cheaper to buy a reworked set of 72 and newer heads,,,
if you have a higher compression 327 engine with smaller chamber heads you
may probably want to buy a !
> later set of heads with a larger combustion chamber and install them on
your block,,,the higher compression heads you dont want can be easly sold to
a corvette enthuisast or some one who is builing a race engine.. if you
remove your valve covers you can obtain the casting numbers, as well as
determine the year they were made from the casting ID, on the front of the
head there are distinct casting markes that help Id them too, but the best
way is to pull the valve cover,,, becareful when buying heads,there are some
heads that are of lighter casting that are undesireable,,They are prone to
cracks because of the lihter casting and poor circulation.. you can forward
your casting numbers to me and I can look them up and give you the
information on your heads,, someone may have allready installed later heads
on your engine and you may not need to do anything.. good luckRichard57
cameo
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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