In the past i have used MLS head gaskets to make up the difference on OHC engines, tho i have never machined a PRV-6 head tho, you just have to be careful about finish quality it has to be really smooth (cant find actual spec in my book..). If you dont make up the difference you will get retared timing. shims should be avalible. as for warped heads a good way to check ids put the head on the table and put the cam in the head. if it turns freely the head is't warped. if it is difficult to turn than the head must be straightened. and to correct my previous post the total machining of head and block shouldn't excede .020". darkstar -----Original Message----- From: Dave Swingle [mailto:dswingle@xxxx] Sent: September 11, 2002 5:12 PM To: dmcnews@xxxxxxxxxxxxxxx Subject: Re: [DML] Head assemblies > Minor problem here. It's kind of difficult to magnaflux an > aluminum head. It's not magnetic. > > Also - you are NOT supposed to grind heads on the PRV, if you > do more than microscopically the front end plate will no longer > fit. (This plate covers the whole front(belt end) of the engine, > including the heads.) If the heads are much shorter than as-designed > you'll have a problem. > > This is explained in the technical manual as well (I believe, it's > been a long time since I re-read it!). > > Dave Swingle [moderator snip]