I will third the motion on verifying pressure with an aftermarket gauge........sooooooo easy to do........stock Vette gauges are crap at best.....
But lets back up.......if you hear a knock....an oil pump IS NOT going to fix it....and in 30 years of building small blocks....I have NEVER seen an oil pump wear out to the point where it will not push pressure.....
And a couple of more things.......replacing the pump is a relatively easy job on a Vette....but you better know what you are doing. The pickup needs to be brazed or welded to the pump AFTER you check the depth of the "foot" of the pickup......you need 3/4" here minimum.......the driveshaft should be the steel collar type (Melling IS55)......and spend $7 and purchase an ARP stud to mount it.....torque to 25 ft/lbs. with oil.
Forget about the rear main seal if it is not leaking.....if you have never done one with the crank still in, you stand a good chance of boogering the new seal trying to get it in......also, use a Fel-Pro one piece gasket.....make sure you get the right one as the dipstick could be on either side.......

The reason a pump will not cure a knock is that if a bearing is significantly wiped out....no amount of oil in the world will quiet that down....if the knock is upstairs...the only oil pressure related potential knock could be the lifters.......but if an engines bearing are good, it is not the cause.

I have oil pressure and water temp gauges under the hood of my 72' 406 because it is good to know where you are really at........

Particles also have to be smaller than the pickup screen and if they get past the screen....kiss the bearings good-bye.

Jebby

 

So maybe the best thing to do is just put it all back together and leave it along. I have not taken the pump off yet. I did take the top off it with the pickup on it, but it should just bolt back on and put a new gasket on the oil pan and put it back on.

 

Nah....hell, if you are in there....remove the pump and pull the 4 10/24 bolts out of the pump and remove the plate.......inspect the back side of the plate for scoring and pump gears for scoring as well.....just because I have never seen it, does not mean it could not happen, but VERY unlikely. If it is fine.....then remove some rod and main caps (Minding their order and position!) and inspect the bearing.......
Report back what you find......

Jebby

 

no big deal but Melling manufactures a few Cast Iron for sbc that have 2-bolt flange & tube does not enter pump (has gasket) pn 10552, 10552C, 10555, 10555C ... they also accept 3/4" OD press-in ... pretty sure all under $200. Note C-suffix (anti-cav) NOT for idling street cars ... they don't push much oil at idle. None of those are new "sharkbite" pumps; may be a few more bolt-on part numbers for those but I don't know.

several flange Melling bolt-on-only screens depending on pan depth & if for left-turn-only or not: pn 12557, 12558, 12559, 12564, 12566 ... strongly suggest those be safety-wired.

I don't suggest any of above for OP frytex. If he even needs an oil pump, an OE-type stock pump & tube-screen is fine for a mild street motor ... tack-weld tube for insurance but just press-in fine for street car if done properly.

I've used 10552 ... both streetrod & circletrack cars ... and pleased. Again, IMO way overkill for OP frytex.

 

Summit does sell a pump with the pickup already installed and tack-welded in place, set up for the stock pan. I have used them twice for early 70's motors and in both those cases the screen to pan clearance was spot on.

That said, as already mentioned, these pumps usually last "forever" and lack of oil pressure and a knock are likely due to bearing problems. I would check oil pressure first. Sounds like you're already into the motor, in which case proceed and cross fingers, but if it was ME, I already know I'd reassemble it and still have a knock.

If if it's a minor knock, could be various things.

 

Funny, looks bolted on

 

Those 2 bolts are just supporting the extra size of the square pickup. The tube is still pressed into the pump. They found the support was necessary after the added weight broke the tube. With predictable results.

 

If you haven't noticed, Jebby is just down (or up) the street from you and is a guy who knows what he's talking about. Listen to what he says.

 

Just a thought - Put the pan in place (without a new gasket) and run the pump with a pre oiler and a hand drill. See if it builds pressure. You should be able to "feel it" even without a guage but a known good guage will help if you have one. Might save you some work.