I just purchased an engine rebuild kit for my 427/425 engine. Standard in the kit is a High Volume oil pump.

Everything on the engine is stock, except that I am dropping the compression to 9.7 to run pump gas. Cam is just a little more radical than the stock L72 cam. (slightly more duration, slightly higher lift)

This will be a Sunday Cruiser, and will see very little high RPM time. I have heard that with stock bearing clearances, a Hi volume oil pump could create a problem. Maybe emptying the sump, and maybe excessive wear on the distributor gear.

Should I substitute a standard volume pump, or will I be OK with the high volume pump?

Also, I read where you should file a small notch in the lower flange of the distributor shaft housing, (directed at the cam) to increase oiling on the distributor gear. Is this a good thing to do?
Thanks,
Gary

Unreal;

On the high-performance engines (rectangular heads) Chevy used a "Higher Volume" pump with 1.39" tall gears v.s. the standard 1.19" gears. These pumps will provide a slightly higher oil flow without increasing control problems, if you stick to factory style bearings and clearance numbers on the mains and rods. The stock HP/HV pump comes with the pick-up welded to the pump cover from the factory.
If you plan on using aftermarket "racing"(?) style full groove bearings or increased clearances there can be oil control issues with high-volume/high-pressure pumps on any engine.
Chevy sells a replacement Oil Bypass Spring (#3876866 w/green stripe) to slightly increase the pressure if necessary.
Don't know what type of pan your planning on using, but the stock pumps should clear it.
I have some of the Chevy numbers if you need them - post back with questions.

John

Only on the L-88 ZL-1 did Chev use a bigger pump. It has much less volume than the 77 HV pump. Your L-72 came with the std pump and that is what I would put back in it. The Mellings comes with 2 springs use the heavier one. You really don't want the problems that the HV pump can cause in a stock motor.

My bad I quess - I thought the L-72's I worked on had square or rectangular port 840 type heads, 4-bolt blocks and the same HP bottom end parts, Forged/cross drilled cranks (with the HD oiling system) as the L-88/ZL-1's.
Same pump was also used on the later LS-6 & LS-7's - oh, and many truck applications.
I never use aftermarket high pressure/high volume pumps in engines I build for the street or marine use, just stock pumps. Over the counter Chevy stuff - they work just fine and have never failed me or caused lube issues.

Good luck on your engine build up Unreal - post if you need part numbers or more info. graemlins/thumbsup.gif

I had the kit (from Summit) shipped to the machine shop, as he is going to balance it. I had asked at Summit if I should use the standard volume pump. The rep said the high volume one that came with the kit would be fine.
I will stop over tomorrow to look at the pump. My guess is it's a federal mogul. I'll post the numbers and seek advice. Last thing I want is to tear up a new motor because the pump was "too good."

What about the thing I read about filing a groove into the distributor shaft housing to increase oiling to the distributor gear?

Thanks for your help.

ur,
Use the high volume pump if you have it. You dont need it, but it wont hurt a thing. Go to the Melling site and read up on oil pumps, it will give you a much better understanding.

Bill very rarely do I disagree with you but this is one of them. Aside from the extra horse power used and the much faster distributor gear and shaft wear there is the real problem of the excess oil in the valve covers. Sometimes you are lucky but most of the time in a street driven vehicle you will have oil leakage down the valve guides because the seals simply can't control the amount oil there.

You know guys, I'm also about 24 hours away from finishing another engine for a future project. It's a 396/325 that is pure stock except for the roller tip rockers and a 242 extreme energy cam (Comp Cam). I have the Melling 77high volume pump sitting in the box ready to be primed, and now I have my doubts. I went to Mellings web site along with others and found some info about the HV pumps. It seems that the stock pump is recommended for stock engines but most info doesn't go as far as saying the HV will "damage" the engine. I think I will return this one and shoot for the stock pump if the HV won't help the engine any more than the stock one.
Also, has anyone used the 242 BB extreme energy cam from Comp. The tech help said it was just slightly off of stock with a slight rough idile. Any thoughts?