yes a M77 oil pump should be just fine (in your listed application)
,check both the oil pump pick-up to oil pan floor clearance ,
and oil pump drive shaft length very carefully
OIL PRESSURE read on the oil pressure gauge is a MEASURE of RESISTANCE to oil flow, you can REDUCE the pressure the gauge reads by either increasing the engine clearances or REDUCING the oil viscosity (thickness) so it flows thru the clearances faster with less resistance.(OR INSTALLING A SLIGHTLY WEAKER OIL PUMP BYE_PASS SPRING,that limits the pump pressure before it allows some oil to re-circulate back through the bye-pass valve ,from the high pressure back to the low pressure side of the pump impellers, but only the max pressure you reach is limited by the bye-pass spring,in your oil pressure bye pass circuit and its that spring resistance determines the point where the bye-pass circuit, opens and limits max oil pressure, but the bye-pass circuit has zero to do with anything else, if its functioning correctly,
there are many oil leakage points(100) in a standard Chevy engine.
16 lifter to push rod points
16 push rod to rocker arm points
32 lifter bores 16 x 2 ends
10 main bearing edges
9 cam bearing edges
16 rod bearing edges
2 distributor shaft leaks
1 distributor shaft to shim above the cam gear(some engines that have an oil pressure feed distributor shaft bearing.)
once oil exits the bearings or valve train it flows mostly by gravity back to the oil pan sump, but a properly designed windage screen and crank scraper correctly clearanced allows the spinning crank/rotating assembly to act like a directional pump that drags the vast majority of the oil flow back to the sump, by design.
your 55 psi at idle serves no purpose as 15psi-25psi is all thats expected in a new engine with tight clearances using a good 10W30 oil, if your using a higher viscosity than 10w30 its reducing oil flow rates and reducing heat transfer rates, Id suggest using a good 10W30 oil. and use of a 7-8 quart, baffled oil pan and windage tray
GM Small Block Performance Pumps
10550
High volume performance upgrade for M-55HV.
25% increase in volume over stock oil pump.
The 10550 housing and cover are CNC machined and phosphate coated.
The lower pressure spring is included to reduce pressure if desired.
Includes intermediate shaft with steel guide. Uses 5/8” press in screen.
10551
High volume performance upgrade for M155HV.
25% increase in volume over stock oil pump.
The 10551 housing and cover are CNC machined and phosphate coated.
The lower pressure spring is included to reduce pressure if desired.
Includes intermediate shaft with steel guide. Uses 3/4” press in screen.
10552
High volume performance oil pump.
10% increase in volume over stock oil pump.
The 10552 is manufactured with the drive and idler shafts extended to allow for additional support in the cover eliminating dynamic shaft deflection at increased RPM levels.
The cover is doweled to the pump housing to assure alignment of the shaft bores.
Screw in plug retains relief valve spring instead of pin.
Relief hole in cover uses screw in plug instead of pressed cup plug.
All bolts are self locking socket heads, with the wrench supplied.
The housing and cover are CNC machined and phosphate coated.
Includes intermediate shaft with steel guide. Uses both 3/4” bolt on or press in screen.
The lower pressure spring is included to reduce pressure if desired.
Patent No. 5,810,571.
10552C (Anti-Cavitation)
10552CHigh volume performance oil pump.
10% increase in volume over stock oil pump.
Same as the 10552 with the addition of grooves machined in the body and cover. The grooves reduce cavitation effects in high RPM applications.
Includes intermediate shaft with steel guide.
Uses both 3/4” bolt on or press in screen.
Using this oil pump will reduce pressure at idle.
The 10552C uses the high pressure spring only.
Racing Applications Only.
Patent No. 5,810,571.
10553
10553High pressure performance upgrade for M-55 & M-55A.
Standard volume oil pump.
The 10553 housing and cover are CNC machined and phosphate coated.
Manufactured with pink spring installed for higher pressure (M-55A).
To change pump to lower pressure (M-55) install the supplied yellow spring.
Includes intermediate shaft with steel guide.
The 10553 uses a 5/8” press in screen.
10554
Performance upgrade for M155. Standard volume oil pump.
The 10554 housing and cover are CNC machined and manganese phosphate coated.
Manufactured with pink spring installed for higher pressure.
To change pump to lower pressure install the supplied yellow spring.
Includes intermediate shaft with steel guide.
The 10554 uses a 3/4” press in screen.
10555
High Volume performance upgrade for the 10550 oil pump.
25% increase in volume over stock oil pump.
The 10555 is manufactured with the drive and idler shafts extended to allow for additional support in the cover eliminating dynamic shaft deflection at increased RPM levels.
The cover is doweled to the pump housing to assure alignment of the shaft bores.
Screw in plug retains relief valve spring instead of pin.
Relief hole in cover uses screw in plug instead of pressed cup plug.
All bolts are self locking socket heads, with the wrench supplied.
The housing and cover are CNC machined and manganese phosphate coated.
Includes intermediate shaft with steel guide.
Uses both 3/4” bolt on or press in screen.
The lower pressure spring is included to reduce pressure if desired.
Patent No. 5,810,571
10555C (Anti-Cavitation)
High volume performance upgrade for the 10550 oil pump.
25% increase in volume over stock oil pump.
Same as the 10555 with the addition of grooves machined in the body and cover. The grooves reduce cavitation effects in high RPM applications.
Includes intermediate shaft with steel guide.
Uses both 3/4” bolt on or press in screen.
Using this oil pump will reduce pressure at idle.
The 10555C uses the high pressure spring only.
Racing Applications Only.
Patent No. 5,810,571
10990
High volume performance upgrade for the M-99HV-S.
Increase in volume of 25% over stock oil pump.
The 10990 is a Big Block style oil pump made to fit the Small Block applications.
The drive and idler shafts have been extended to allow for additional support in the cover. Additional support eliminates dynamic shaft deflection at increased RPM levels.
The cover is doweled to the pump housing to assure alignment of the shaft bores.
The relief valve has a screw-in plug instead of a pin.
The housing and cover are CNC machined and phosphate coated.
An additional spring, the original stock replacement is supplied which will reduce bypass pressure if needed.
Includes intermediate shaft with steel guide.
Uses 3/4” press in screen.
Patent No. 5,810,571.
10990C (Anti-Cavitation)
High volume performance upgrade for the M-99HV-S.
Increase in volume of 25% over stock oil pump.
The same as the 10990 except with the addition of grooves machined in the housing and cover. The grooves reduce cavitation effects in high RPM applications.
Using this oil pump will reduce pressure at idle.
Includes intermediate shaft with steel guide.
Uses 3/4” press in screen.
Racing applications only.
Patent No. 5,810,571.
GM B.B. Performance Pumps
10770
High volume performance upgrade for M-77HV.
25% increase in volume over stock pump.
The housing and cover are CNC machined and phosphate coated.
The lower pressure spring is included to reduce pressure if desired.
Includes intermediate shaft with steel guide.
Uses 3/4” press in screen.
10774
10774Standard volume performance upgrade for M-77.
The housing and cover are CNC machined and phosphate coated.
The lower pressure spring is included to reduce pressure if desired.
Includes intermediate shaft with steel guide.
Uses 3/4” press in screen.
10778
High volume performance upgrade for the 10770.
Increase in volume of 25% over stock oil pump.
The drive shaft has been manufactured from chrome-moly steel.
The drive and idler shafts have been extended to allow for additional support in the cover. Additional support eliminates dynamic shaft deflection at increased RPM levels.
The cover is doweled to the pump housing to assure alignment of the shaft bores.
The relief valve has a screw-in plug instead of a pin.
The housing and cover are CNC machined and phosphate coated.
An additional spring, the original stock replacement is supplied which will reduce bypass pressure if needed.
Includes intermediate shaft with steel guide.
Uses 3/4” press in screen.
Patent No. 5,810,571.
10778C (Anti-Cavitation)
High volume performance upgrade for the 10770.
Increase in volume of 25% over stock oil pump.
The same as the 10778 except with the addition of grooves machined in the housing and cover. The grooves reduce cavitation effects in high RPM applications.
Using this oil pump will reduce pressure at idle.
Includes intermediate shaft with steel guide.
Uses 3/4” press in screen.
Racing applications only.
Patent No. 5,810,571