First Generation Firebird-L Mailing List
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This seems to be more of an issue with engines that have high compression
heads, [72cc]. Over the years as the octane was reduced, owners had to retard
the timing to avoid pinging. When timing is set closer to TDC the combustion
pressure & temp goes up. To remedy this issue, the options are installing a cam
with more overlap [to reduce dynamic compression] or change to lower
compression heads. The problem with a big overlap cam is poor idle and low
vacuum which affects other things. Sure, there are good cam grinds, it's just a
matter of find one that best fits your application, [use, engine mods, trans,
vehical weight etc.].
+1 on the water pump plate to impeller clearance - this is probably often
over-looked.
I chose to replace my #62 heads with 6X heads, [72cc --> 84cc]. Sure I lost
some power, but I can run on 87 if need be. On the highway [w/ T400 & 3.23:1
diff ~2700 rpm] my engine settles around 200-205F.
I'm not suffering too much, I have a hi-lift cam, modified intake & heads, an
exotic distributor curve and run 91 octane or a mix of 100 octane race fuel.
Needless to say it gets out of the hole nicely... ;)
PeteJD
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