Does the "N" on Enginetech piston rings signify Up

https://www.gmtruckclub.com/threads/96-chevy-5-7-fuel-pressure-issue.1479391/

This thread has a few ideas on what to look for.

valve train damage --stuck open valve lifter failure spring spring retainer popped etc--blown piston ring s -hole in piston -damaged cylinder wall

IS the leak at the front

was the area all cleaned down after the work
looking at the youtube teardown
sump gasket , rocker cover gaskets
or rear engine seal
if its burning oil the valve stem seals and or piston rings
https://www.youtube.com/watch?v=-gkxF7wKIdk

You need to send it to someone who specializes in this . There are many . The computer will need to be reflashed as well and they will thin down the harness to your application

Probably not lifters. Huge well documented issues with piston skirt slap in the vortec engines when cold. Pistons made at one location and blocks at another. Manufacturer will not make any repairs. So don't go there, you'll be wasting your time. Lots of documentations from both manufacture and owners of no damage noted after high mileage. Options are to live with it, let it warm first before driving or rebuild engine- bore one size and replace pistons with a better one with a coating on walls. Did one for a gentleman with 59,000 miles 3 years ago and he's totally happy. He could not live with the noise it was making. My Wifes 2000 Yukon has same problem. If you have a diesel.. not my area.
Good luck

google: vortec piston slap, read , get mad, welcome to the club!

firing order for 5.7 v8 is 1-8-4-3-6-5-7-2 mostly all of the chevy v8s are the same firing order. the rotor button in distributer turns clockwise, the cylinder numbers are 1-3-5-7 on drivers side, 2-4-6-8 is on passengers side. To get started get your distrutor cap[new one] look on the top you will see a #1that's where you begin you must know if if rotates clockwise or counter clockwise start in that direction then follow the firing order and cylinder line up. good-day!! if cap is not marked, just pull out #1 plug, put a straw or similar in plug hole on top of piston. turn engine over by crank in front of vehicle with a wrench, when the piston comes to the very top just before it starts going down. this is tdc. and rotor button should be pointing to #1 wire on dist, cap. follow from there. good-day !!

I had a chevy 2002 avalanche,2004 chevy tahoe both after 20,000 miles developed a mild lifter or slight bearing knock.When I confronted chevy with this problem they stated this was normal for the 5.3 liter v8.Being a mechanic myself didnt think this sounded right.My friend has a 2003 gmc yukon and motor sounded same way.I no longer own my chevy,But my friend still has yukon with 150,000 plus miles and yet it still knocks when you start it.this is just a problem with chevys and other gm products.

your problems might be internal with the piston rings in the motor,its probably due to age-you took all the correct steps,check compressions and were that takes you.hope that helps you out
good luck!

1 6 5 4 3 2 It turns clockwise. if you have the normal distributor cap number one is at 5 o'clock. if you have the flat (edi) distributor the firing order is the same but number one is in the middle of the driver side. The pistons are numbered, #1 front driver, #2 front passenger 3 is behind 1 5 is behind 3. Odd on the driver even on the passenger

I just checked Ebay, and there are two listed. You might try Craigs List.

(Tips from me:
Port the Vortec head. Open the Intake and Exhaust ports, by smoothing them out, and smoothing the casting sprue lines out.

Put the Intake gasket, and the Exhaust gasket on the head, (After marking the area with Prussian Blue)
Scribe the opening of the gasket, onto the head, then match the ports to the scribed lines.

You also should round the valve guides top surface. (Where the valve stem meets the guide) There is a square edge that needs to be rounded. This square edge interferes with the fuel/air mixture, as the sharp edge breaks the fuel/air mixture down into droplets.
You want to keep the fuel/air mixture atomized, Not droplets.

Also narrow the casting that comes up the side of the valve guide. (Squared off shape that follows up the guide, and makes the Vortec shape swirl shape in the Intake port) Narrow it to more of a small rounded edge.

Do not polish the Bottom of the intake ports. Leave them as a rough casting. Smooth, and polish the Sides, and Top of the Intake port. (Do not get Extreme! You'll go into the water jacket with your die grinder! Factory may have had a casting shift that day. Just smooth things up)

Makes a nice swirl pattern for the fuel/air mixture.
If you polish the floor, (Bottom), of the Intake port, you will create Two swirl patterns, and they will collide with each other, making droplets again. (They cancel each other out. You want one nice swirl pattern flowing through the Intake port)

I can bring my 1985 Fiero up to 155Mph, (On dragstrip set up for this, tires, and proper safety equipment used). I can also 'Keep my foot' out of the throttle, and get 45 miles to the gallon on the highway.

You can use flat top 350 Chevy pistons. The 2.5 Vin R Fiero engine has a 4 inch bore like a small block Chevy. The pistons can be put on the Fiero rods. Same wrist pin size. The piston drops down into the engine block, about .030 below deck height.

(Wrist pin to piston crown height, is .030 shorter with 350 Chevy piston, compared to stock Fiero piston. You can buy 4 - 350 Chevy pistons AND rings, compared to the price of just the rings, for a Fiero!)

(Thirty thousandths. Real close to 1/32nd of an inch. .03125 is 1/32nd of an inch)

Fiero's have dish head pistons, so the drop in deck height, and using a Flat Top 350 Chevy piston equals out. (Better flame travel with flat top piston. Better burn, more power. Uses more of the fuel/air mixture than a dish head design)
If you can't afford to have them balanced, use a beam scale, and balance them yourself.

I can bring my 1985 Fiero up to 155Mph, (On dragstrip set up for this, and proper safety equipment used). I can also 'Keep my foot' out of the throttle, and get => 45 miles to the gallon on the highway. (Throttle Body Fuel Injection. TBI)

Makes a V6 Fiero cringe!