The oil pressure will always drop as the oil temperature goes up. When the oil gets really hot, 260-280 the hot running pressure will be around 65.  There are folks who claim 260-280 is too high. It's not. G.M. actually used to say up to 300 is okay (measured in the pan). The oil can take it, so can the bearings, no problem. For that reason, I set up my oil pumps to make very high initial oil pressure. I always run an oil cooler, it needs it. After running sustained 4500+ everything gets pretty warm. All the clearances have to be right, really good parts used or it will grenade.

I am asking for opinions, although I think I know what the problem is. I was out testing a new engine the other day, and it was working great. Good temperature, good oil temperature, pressure at about 80 hot.  I was starting to push the rpm up to full power, and at 5100 the oil pressure suddenly dropped to 20. I brought the speed back to idle, and the oil pressure recovered.  I did a couple more laps, and the oil pressure stayed at 80, but not going to full power.  I think it is pumping the sump dry at high engine speed. Anyone else encountered this?  The oil pan I have is a Moroso that is supposed to be good at controlling windage.  It only holds 7 quarts though.  I have a feeling I am going to have to modify the pan to hold a lot more, like maybe 10-14 quarts. I am hoping that will be the fix, otherwise, the only other alternative is to go with a dry sump. The engine is a 540 and will turn a well-loaded A3 Aggressor at 5600. I did cut the filter open and take the element out for inspection, and there was nothing significant in it so I know that there was no damage, but I cannot run up to full power until I have this issue resolved.

This is my 19' Legend race boat. It was built for white water marathon river racing. I have had this for over 20 years, and I just use it as my hotrod. This year, I built an all aluminum 540 with mechanical fuel injection. I haven't put it in the water yet, but the engine has been dyno tested, and also run on the trailer with a wet kit to make sure there aren't any leaks. The boat is a welded aluminum vee bottom with a Dominator jet pump. It should show about 6000 with an A3 impellor.

Yes, I run it in my boat and everywhere else I can.  I use it in my lawn mower, snow blower, weed eater. It is an inexpensive high octane alternative to race gas, so long as compression is not too high.  I use it as detonation insurance in my boat, and I have never had any troubles with it. It has stabilizers in it so it stores well.  There is absolutely no alcohol in it (which reduces mileage), it is 100% gas.  I found that the small engines I run like it much better than pump gas. 

I have found that over the last few years, there are more and more parts coming from China.  Appearance wise, they look as good as anything domestic in many cases. (There is some crap out there that looks it too). However, with Chinese parts the quality of the metal is unknown, and this is where the problem lies. I am referring to crankshafts and connecting rods particularly.  While the final product may be comparable to something made in U.S.A., it can just as well not. They do make batches of parts of course, and sometimes the metal is spec, but other times it is not. (They will use whatever is available. on a given day). Unless one has access to proper testing equipment, one cannot be sure what it is.  I do my best to buy only parts made and machined in the U.S.A., even though they are more expensive.  Not only am I sure of the quality, but it also helps to keep tradesmen employed.

With regards to your water cooling, I have had good success with an open bypass as well as a regulated bypass.  This setup allows the thermosat to control the engine temperature. The key is to be able to maintain 15- 20 p.s.i. That's how the cooling system is designed, and it works that way, no heating up at idle, and no overcooling at running speed. For what it's worth.

Mk IV.

I have a couple of items for sale which are surplus.  A Vertex magneto, rebuilt by Don Zigg 700.00. A Dooley 10 qt oil pan 150.00. No issues with either item.

I noticed in your pictures the bell housing you are using.  Sorry to get off the subject, but I would one of those bell housings, and I don't know where to get one

The injector has a provision for mounting the nozzles in a different location, or running two sets of injectors for some applications (nitro?). I run the nozzles in the upper position, as Kinsler set it up. I use two of the lower nozzle positions to mount my throttle cable bracket.

I finally got it done- soon  off to the dyno.  Wonder what it will do.

That's a thought!