YES.
Are you spinning the pump the right way? You have oil in the pan? Does the drill "load up" when you run it? It should drag some as the pressure starts to build. If not, you have plugs missing (behind timing cover or under rear main cap,) there is one also. Somtimes missed by inept rebuilders. Check pickup. Does it have a collapsed hose? not sure what you have for pickup, should be 3/8 to 1/2 inch off floor of pan. New pump? or old pump with relief valve jammed open? Main bearings in properly? the ones with holes go in the upper side of the block. A very costly mistake if you try and start the motor.
Stick with a Melling Select STANDARD VOLUME pump, no need for high volume unless you are pushing 500 hp or more, and have an 7 or 8 qt pan.

I agree Formula 18.. some like to do these things but we learn the hard way.. We also learn from friends and from people here on OSO Not everyone is an expert like Rylar but we enjoy what we learn and how we learn,,, Bad comment Rylar

I forgot to hook up one of my oil lines before priming one time. The oil shot about 20 ft in an instant. And this was with a little 3/8 drill on the priming tool. Another time, I hooked up the remote oil lines backwards. Because there was an anti drainback valve in the oil filter, pressure in that line instantly went sky high and the drill bogged right down. These are simple things that can go wrong and the results. Bcause of the symptoms the poster is having, I would guess it's the plug under the main cap or the plugs under the timing cover. All of the lifters are in aren't they? Good luck.

I guess some of these PRO ENGINE BUILDERS were born with this sixth sense of engine building.Just started doing it because they had the gift,never had to ask a question or get help from anyone,HMMMM.Oh I guess that could happen.JOHN SR

I just read this thread and a good point was just made. Are all the lifters in with pushrods, rocker arms, etc? If so, then as mentioned, a plug(s) were left out under the rear main or behind the timing set. The one under the rear main bearing is easy to miss in a SB.
Formula, you should not be able to hold your finger over the hole. It should not only push your finger back, but should blow oil EVERYWHERE. You should be able to sneak out the timing cover without pulling the engine. Not sure about that particular boat, but sometime it's easier to just pull it and work on the stand. You should be able to make 40+ #'s with a decent cordless drill and a standard volume pump. Let me know if I can help.
Eddie

thanks guys motor is coming out this weekend...stripped it down just waiting on using the lift at a buddys house

I had a low oil pressue issue on a new motor earlier this year and discovered that the builder had installed the correct oil pump; but, the low pressure spring. Consequently, my oil pressure shot up to 45 PSI and then stopped. Once I installed the high pressure spring, my pressure went right up to 70 PSI +.

I'm wondering if this spring might be bad in the pump which would allow the pumps internal bypass to open immediately and not generate any pressure.

One more thing to check.

Good luck and let us know what you find out.

why would you not prime the pump before installing,it only takes 1 minute to do,the pump gears&shafts need lubrication,just as much as bearings etc.im not being a smart azz,i just dont understand why you would not do this 1 minute job.

My point has been the same throughout this thread: The original poster has a NO oil pressure condition. Whether or not assembly lube or oil was used in the pump during installation, is NOT causing the pump to not produce oil pressure.

If you take an oil pump out of the box, install the pickup, submerge the pickup in oil and turn the shaft, either by hand or with a drill... the pump will pump oil... unless there is something physically wrong with the pump itself. The pump itself does not require priming to draw oil from the pan. This is not an opinion, it is a fact. When turning the pump in the pan with a drill motor and priming tool, you are priming the entire engine's oiling system... filling all galleys and passages so that all major components see oil pressure the second the engine fires. This procedure has nothing to do with priming the pump itself, with respect to it drawing or not drawing oil from the pan and creating pressure.

Whether or not to put oil or assembly lube in a pump before installation is another subject, but not relevant to the original poster's issue.

u say it is fact that the pump will self prime,you may think it is a fact,but the mechanical engineer at mellings sais you must put oil in the pump&turn the shaft by hand until the pump is primed,fact is,unless you know something that the engineer doesn,t know,YOU SHOULD FOLLOW DIRECTIONS AND PRIME THE PUMP.i have been doing it this way for 30 years,and will keep doing it that way.it is a free country,so carry on,good luck.