Maximum oil pressure
 

What is the maximum oil pressure a 427 Shelby block can tolerate on starting and running without causing any problems.

I think your oil filter bursting, not the block, would be the limiting factor.. I'd say in excess of 100psi..

Dave

Oil filter bursting pressure is a consideration but unesss you are talking about a belt driven dry-sump oil system, a continious high pressure with high volume will challenge the distributor drive. If you do a search or remember members have worn the distributor drive teeth and cam teeth to almost nothing, with some teeth breaking. The pin in the distributor shaft is a limmiter makeing the hole larger for a larger pin weakens the shaft and moves the point of failure to some plase harder to get to. Press on gears are a big hassel. MSD supplied (sold) me with a dandy 1/8" X 3/4" true roll-pin. My engine uses a "Precision" blueprinted Melling high volume pump with the optional pressure shim added. The truck version with a 5/16" hex drive rather than the car 1/4" hex . A chromemolly drive shaft is available with 5/16" hex on the lower end for the truck pump and a 1/4"hex end ontop for the car distributor. My original pump was trying to round off in the pump drive. I had the original spring-pin in distributor fail once when I got carried away with the throttle before the oil had any temp showing. The engine just quits running ,no damage and it wasn't hard or expensuve to repair. Normal pressure releif on a high volume pump set around 60 to 75 ,don't get carried away with throttle untill oil temp comes up to 140° and use a true roll-pin from MSD . My concern is the restriction of the single Ford style filter. GM has a larger threaded hole and I'd prefer having two parrallel filters rather than two in series for more volume and or less restriction. I think the oil is filtrered just fine by one trip thruogh a filter. But I haven't concured that problem yet.

As Michael C Henry noted, the block isn't the failure point, the filter is. 427 side oilers came from the factory with 125 psi. Not everyone agrees high pressure is needed; I believe it's a help to get the oil out to the rods on top oiler blocks. The pressure itself doesn't do anything except push the oil to where it's needed. If you want to run that high pressure, the Fram HP 1 filter is a direct replacement for an FL 1a; it has a higher burst housing and the neoprene seal is considerably deeper so it won't blow out. Sadly, to my knowledge the HP 1 doesn't filter any better than the standard Fram unit.

Dan