any suggestions on where to start to determine the cause of:

540 bbc, bottom end and top end freshened last season. runs strong, idles fine, no other gauge anomoloies. oil pressure at cold start up at 60-80 at idle. i have an oil t-stat, oil cooler. get on plane, run 2500-3000 to warms things up....oil temp goes to 220, then the tstat opens and it stays around 200-225..oil pressure at 3000 is solid 60.. run rpm up to 3500-4000 and i saw the oil pressurre flutter down to 40..back off throttles to 3000, press goes back to solid 60...no high temps, no performance issues...just very nervous about oil pressure doing strange things...other than pull apart to inspect bottom end, any suggestions???

thank in advance

It's the sending unit on the engine. I just had the same problem.

Faster I ran the engine the lower the pressure showed, and it would flutter bad.

Changed the sender and all is good.

i come from the school that there are no inexpensive solutions to boat issues...would defy the laws of boating if it was just the sender!!!
new sender ordered.....probably going to temporarily hook a mechanical gauge up to another port just to confirm...
thanks
gm

hopefully you are not sucking the pan dry,had this happen on a blown 468 BBC and on a 514 ford

Try removing any Teflon tape or other sealer from the sender.The sender needs clan contact with the block.

Thats no joke!!!!

Iam from the same school, nine out of 10 times it is the sender but ALWAYS check with a mech gauge and dont run till you do

got a break this time...oil pressure sender was bad....
$40...30 minutes...
thanks for the responses

I have a permanently mounted mechanical oil pressure gauge in the engine compartment, peace of mind when the electrical gremlins strike.