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					Originally Posted by tjs44  Same cam same CR  same CI I dont think any diff in sound on a RA III engine and a RA V engine.Been there done that.JMHO,Tom | 
	
 Tom we were talking about the difference in compression ratio in the sound not necessarily the d port Vs V port . I only used the V and D port because that’s what I had for comparison in my garage in different compressions, and wanted to explain the difference  .  That the RAV was a higher performance version and higher compression.  Yet the D port lower performance engine w low compression sounded the same .   In fact most people who hear both side by side idling  feel the Turbo car sounds nastier and snottier even though it’s far lower compression , smaller cam , and blows through the turbo which knocks down some decibels. .   RAV is a roller cam 650 lift range about  a 112 LSA  and the d port turbo car is a solid flat tappet in the 550 range 114 LSA. 
I’ve built RAIV both ways stroker w low compression and original w high compression and I dint feel there was any dicernable difference in the way they sounded.  We are really only taking about 1 point to 1.5 points  of compression between the two on those engines if the original is built to 1969 NHRA specs even For a stock eliminator to a drivable on pump gas stroker  RAIV.