I had a 327/210 and have a 327/275, both with stock cams. The 327/275 always sounded better idling. Could CR, heads, intake, and dual exhaust, account for this?
I always assumed the cams were different.
The cams were the same
The difference was the heads, compression, intake and exhaust system
The engine designation (L79) is the same for the 327/350hp and the 327/325 hp, so they are essentially the same engine. 68 Corvettes with the L79 were rated 327/350hp, whereas the Chevelle L79's were rated at 325 hp. ...
... GM just wanted the corvette engines to be rated higher ...
While GM 'liked' to have the 'Vette differenciated by being the "King" in HP and Performance of the Chevrolet lines - there are multiple examples of that not really being the case ...
There were specific tuning, calibration of carburation and set-up differences in the two engines to get the rated (SAE 'Gross') HP/Torque figures that were published for each engine. As an example of carburation differences, a '67 Chevelle 327/325 used a Holley #3807 (4150 type) while the same year Corvette 327/350 used a Holley #3810/14 (4160 type) - the two different carbs and their calibrations were just one of many slightly different tuning calibrations done to these engines.
There were also cases where engines were purposely given 'odd' published ratings to satisfy certain GM policies designed to meet formulas for production vehicles. The "Z's" are an excellent example of this
... Can anyone be more specific than this? I've been looking for written detailed specs, but haven't found them as yet...
Can you be more specific
There are bunches of published and web sources for configuration spec.s on these various engines. The "Mortec" web. site is an excellent source of much of this info. Link - http://www.mortec.com/
Many of the various 'Corvette' sites also have data in their pages and links. ALWAYS double check one site against several other sources, incorrect data tends to get established in some and spread by some others ...
The compression ratios varied quite a bit on the 327 over the years. In 1967, and for most '68's, the 327 came in 8.75:1 CR for the 210HP, 10:1 for the 275 and 300HP unnits and 11:1 for the 325 and 350HP engines.
If you can give a year, model and state-of-tune (HP) I, and others, can probably give you the majority of the factory configuration spec.s for it.
Hope some of this helps;
ps: if you PM 'pdq67' he will give you all kinds of spec.s on the 'little' 327's AND 'stories' to go with them
j/k - Luv Ya Paul