Hi John,
   I wrote a message earlier and I don't know if it went through or not so I'll do it again . I worked on the 1755 today for a short time and I took out the pressure relief valve in the main oil gallery . It didn't come out easily . I measured it out to 1-5/16" -a 1/16"  short according to my shop manual . So I found a nut that would fit inside the hollow valve under the spring . This fix made it about 3/32" too long but I put it together anyway . I didn't measure the compressed length at 10lbs . I started the engine and it had 60+ psi , let it warm up good at 1200rpm , pressure dropped to 40 psi at 800 rpm . Big smile ! drove it about two miles and when I got home pressure was down to 10psi at 2000rpm . Big smile was gone !!! Engine still sounds good and runs great . Does 18.5 -19 mph according to the speedometer . 
   To do the leak test can I convert a propane tank ? I haven't found a freon tank yet . People just don't want to part with them . I have an old style propane tank that I don't use anymore but I don't know what kind of pressure they can take . This test doesn't go over 30psi does it ? I tried calling the number that you called me from because I thought you asked me to get back with you this weekend but  you used a calling card number . Good Idea by the way ;-}  What all do I need to do this test ? I have a grass driveway to work on and no shop or barn to put it in . I could use my bosses shop but with no oil pressure now I can't get it there , it's 7 miles from here . Up a creek without a paddle !  <!-- s:D --><img src="{SMILIES_PATH}/icon_biggrin.gif" alt=":D" title="Very Happy" /><!-- s:D --> I always make due somehow . I can get pretty creative when I have to out of necessity Well thanks a lot and I'm hoping to hear from you soon . Randy-IA