I'm willing to bet they swap the pistons for European spec (E series). Like you, I originally thought increased PRV compression was done in the heads, as contemporary Americans did. Turns out Dourvin left the heads alone and increased piston height. Connecting rods may be longer too. Houston's engine *MUST* have higher compression to yield those numbers without forced induction. Plus there was a thread last fall from a new owner with one who was having terrible pre-detonation problems, probably from running too low octane. Could someone on List with a Houston block do a compression test and post the results? Stock E series is 160-170 PSI. Bill Robertson #5939 To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/