stock 350 oil pump vs hi flow

[gcochran223]

The ol 350 is getting freshened up and I'm in dispute between buddys. I'm boring over my 80 4 bolt 350, and one buddy is telling me stay stock oil pump other is saying hi flow. I plan on using my stock 5 quart pan.the point of it being hipo will cause my motor to run dry possibley at cruising rpm.which makes sense to me. Daily driver but getting some flat tops and vortec heads. Any info appreciated.

[Camfirchev]

From what I have been told, I have seen engines built with more clearance in there main and rod journals to allow a quicker Rev, to make up for the extra clearance they will run the high flow oil pump.   Both pumps on a stock engine work fine, but your high flow pump will bypass more oil than a stock pump, but still run the same pressures.

[bake74]

From what I have been told, I have seen engines built with more clearance in there main and rod journals to allow a quicker Rev, to make up for the extra clearance they will run the high flow oil pump.   Both pumps on a stock engine work fine, but your high flow pump will bypass more oil than a stock pump, but still run the same pressures.

      Correct, if the engine can not do more oil flow it will bypass.  I know some Vortec heads require a hi-flow pump.  You should do some research on the heads you are using.  If you list specific's on the heads someone will chime in. 

[gcochran223]

i ordered the rebuild kit today for my motor and included is a Oil Pump, High-Volume, Standard Pressure. and i spoke with summit about this being a daily driver and he said it was meant for a basic rebuild. hopefully it wont cause a issue. the motor goes to the shop friday to get bored out and im dropping off pistons etc for them.

[Jason S]

Just about every engine book out there says a stock oil pump is absolutely fine for a street engine. 

However, a trusted mechanic of mine who is GM trained and then went on for 40+ years running his own shop and a circle track racer (running Fords if that matters) recommends a high volume pump (not high pressure) for any replacement...  That being said, you'll have a new engine with new bearings so you shouldn't need the extra volume. 

For my $0.02, use a stock pump.

Also, whatever pump you use, cheap insurance is to press the pickup into the pump and make sure it is oriented correctly then tack weld the pickup to the pump.

There are other postings about this same subject on this site.  Most point toward an aversion of the high volume/high pressure pump for an engine mainly used on the street. 

Did your kit include a new oil pump drive? Also if you haven't done so, as you're using flat top pistons you might double check the compressed height of the head gasket and make sure the cylinder deck height and the flat top pistons will allow proper quench for your Vortec heads.

[gcochran223]

i have to get a different oil drive and a buddy said i needed a better one. I'm hoping the performance shop will know to check these issues come Friday when i drop it off with my buddy(who has more building experience). I'm just the tear down, delivery,check book on this one.I'm trying to get second opinions on everything somewhat cause i don't like having all my eggs in one basket.

[Jason S]

I am definitely no engine building expert. But if you're using a hi-volume oil pump then use the correct drive.

Again, my 2 cents... Mostly these are lessons I have learned from my mistakes...

Presuming you are using a flat tappet, two piece seal block.

You should probably have the engine decked if you're going to use flat top pistons. Decking amounts should be based on the compressed head gasket specs + piston depth in your block so that you have an assembled height correct quench ratio...

For any cam choice, it is easiest to call the cam company with your vehicle specs (i.e., engine, heads, exhaust, vehicle weight, auto/manual trans, gear ratio, tire height, etc.) to get the cam that best suites your vehicle; in my case I didn't and my friends "in the know" were wrong about cam specs.  Don't order pushrods until you have the actual cam in place, at which point you need to measure the actual pushrod length needed.  Are you using self aligning rocker arms  (i.e., stock Vortec type) or are you going to use pushrod guide plates?

Are the heads new or rebuilt?  It wouldn't hurt to check the assembled height of the valves to make sure that everything is at the same height.

Assuming you are using a flat tappet cam, most of the cam companies recommend made in USA flat tappets (mechanical or hydraulic) along with a good break in lube. You don't want to wipe out your camshaft when you start your engine.  Make sure the valve springs on your head match the required springs for your camshaft.

Most of this is may just be a case of double checking, but it is very frustrating when you build one thing and it turns out to a disaster...

[VileZambonie]

Use a standard volume pump unless your clearances exceed .0025"

[bake74]

Use a standard volume pump unless your clearances exceed .0025"

      See I knew someone would chime in and tell you when you needed the high volume pump compared to standard pump.  I just gotta say this forum and it's members are awesome.