baxsom

i am getting ready to replace a rear mail seal that is getting increasingly leaky.

i figured since it has to come off anyway i might as well replace the oil pump.

everywhere i look whether it is autozone or ecklers it has the choices of hi perf or non hi perf.

for a 4 bolt main 72 454 which one do i need.

(it does have hi perf stamped on the side of the block by the filter if that means anything)

hugie82

Go for the Hi Perf/Hi Vol/Hi Pres means the same thing. More oil pressure is good but some pumps go to high. I use the Mildon pumps from Summit Racing w/ no Problems. Also get the new pick up tube w/ a hold down bracket so it don't come out!!! Ask me how I know

Mike Ward

If you research this properly, you will find that the so called hi perf pumps have no legitimate use on the street. You'll also find out that there is a huge difference between a high pressure and a high volume pump.

You do not want either for a street driven car, despite what Summit tries to sell you.

baxsom

so this is the one i need then
http://shop.advanceautoparts.com/web...S_143019260___

Mike Ward

That appears to be the one. M77

hugie82

That may be true for an Impala w/3:08 in the rear but run a big block vette hard down a long highway then pull off into traffic Then tell me what your oil pressure gauge is going too say When your valves are clacking away because you have 10 PSI. Been their done that

swankmg

I agree with Mike Ward. Have built/run several pumped=up small blocks on the street for decades. The high pressure/high volume pump is too much, found that it eats up stock distributor gear on the street. There is a comprimise, typically referred to as the "Z28" pump. Its only 10% over instead of the 25% over in the high press/volume pumps typically sold -- check the Melling lists close, you will find it. SBC with typically bearing clearances just don't need extra pressure.

pats72

Agree with Mike and Swankmg. Have run a standard pump on my BB for the last 5 years on the street and strip with no issues.

d555

I've found that the High
volume pumps will pump to much oil to the top end on highway cruising speeds. These pumps will out pump the capacity of the standard pan volume.
Other drawbacks to a high volume is the associated distributor gear and/or cam gear wear along with attributed spark scatter.
Blueprinting of the standard M77 is the way to go.
Have fun and enjoy!

noonie

OP has a BB
The z28 pump is for small blocks and is a standard volume/high pressure pump. M55A or 10553Select Series.
Standard BB pumps are not the same gpm as SB. Don't think Melling makes a BB 10% pump.

Here is a quote from Melling on the myths of gears and dry pumping.

fauxrs2

Oil pump myths FTW

427Hotrod

I've run HV pumps for years and have never worn a dist gear out yet. If gears are dying...you've got other problems.

A HV pump's real advantage is to *outrun leaks* at lower rpm due to larger race clearances or just a loose engine, or maybe even give you the opportunity to run thinner oils if you want to. You can take a stock pump, install the spring from the HV/HP pump and guess what? You'll still get the exact same oil pressure at higher RPM. The HV will just get to that pressure sooner because gears are larger. You can get over 100 psi in a heartbeat with a stock small block pump with enough spring or shims.

When you get the M77 stock pump, it usually comes with a higher pressure spring packaged with it. You can install it to increase the max pressure into the 65-70 psi range. It will still put out the same pressure at idle and low speeds. You can even take the stock M77 spring and install it in a HV pump. It will peak at 50-55 psi and hold more pressure at idle and low speeds than a stock one. You can use the mid range spring and get something inbetween.

You can also use a stock BB pump on a small block. Many circle track racers do it because they like the *smoother* operation of the BB pump since it has more teeth, as well as the larger pickup tube. Heck, you can put a HV BB pump on a small block too. You can also get a small block pump with a BB sized tube. Hmmnnn...sounds a lot like a stock big block pump with a different part number doesn't it? (it's not..they just drill a bigger hole and charge you more).

You will also find Milodon, Moroso and just about everyone else repackages the Melling pumps. Milodon has come out with an exclusive line of beefier casting SB pumps though. There are a couple of others out there too.

If you're having oil pressure issues from *pumping the pan dry*..what you're really having is oil drain back or windage issues. The pump only puts out what pressure the spring allows. Yes HV moves more oil at low speeds due to the higher pressure it can create....but I doubt that will ever cause enough issue to run a pan dry at those speeds. I've run them for years with stock pans.

I personally like higher oil pressures. My motor has lifters that bleed extra oil through the rollers, so the HV helps keep low speed pressures up. I also add shims to increase top end pressure too. Having 80PSI at 7000+ RPM to me is a good thing. Can it make more power at 40 psi like racers do? Sure..but I don't tear motor down every week either.

All this said,,,to the OP......if it's a stock 72 454...and you haven't had any other issues...I'd just use a stock M77 with the higher pressure spring. If it's got some miles on it....or if you like to bang on it once in awhile...I'd stick the HV in it. It will do fine.

JIM

jackson

Unless there's been a serious failure of other parts, it's more likely than not your present pump is the correct one to continue using. They're about the best-lubed part in the motor; very rare they fail unless they first ingest bits from other failed parts. Basic pump inspection will confirm or deny.

If you do choose HV for BBC ... suggest you look at melling 10777 ... true race quality pump w/ tougher gears & screw-in pickup tube. Call Melling direct; they know what they're doing & they've always been friendly & helpful.

baxsom

i dont think that there is anything specifically wrong with it. idle pressure is about 35.
cruise pressure is around 40.

but if i have to take the old original 1972, 75K mile pump off to do the rear main seal for an extra 30 bucks the comfort of a new oil pump is nice

Reggie Dunlop

Your logic is sound.
There is a difference between high pressure and high volume and for your application neither is needed. A good quality stock replacement pump will work just fine. You could still get it from Chevrolet a few years ago. Do not know if it is still available.

72-LT1

I replaced my pump last summer when I did the timing chain and such. I wanted to go with the higher volume melling pump. I went through 2 different pumps that did not fit because of the baffels in the pan.

Had to go back to the stock pump for it to fit with the crap in the stock pan.