If you heard a loud popping sound, that was my head coming out of my rear..
I dunno what I'm thinking, a busted piston has a definate knock of it's own, the sound is different from a rod or crank, but still a heavy knock..
We should not overlook a collapsed lifter, this knock is half-speed of a rod knock and may pump up AFTER you do 9 million miles of unneded work.
Your timing chain choice, IMHO ANY good double row unit should do fine.
Summit, Jegs, err those dudes in Calif, dangit I can't rememeber the name but they sell a ton of assembled long and short block engines of all makes, grr
Myself, I have here a Milodon Gear Set which I bought for my small block 427 project which is now shelved due to fuel costs.
Another suggestion, adhesives:
#1 permatex = Water Pump, Thermostat Housing, Carb base plates
it's suggested in my GM Service manual. It has NO adhesive ability, but does seal well when holding back coolant.
RTV, I like Gold O2 Safe RTV for the ends of older intakes, timing chain cover and the like.
On the ends of Intake Manifolds, use double the amount suggested per GM manual, inspect with mirror to make sure of full contact.
Using double amount[3-4mm bead] will cause the RTV to bulge out just a little bit on both sides of the intake. This will give you a O-Ring effect which may stay in place during a backfire.
disclaimer for above;
The fit between V-x engines varies greatly, some intakes have a tiny gap between them and the block and others
[like my 90 vette] have a Huge gap.
Old School stuff ->>For Cork Gaskets only,
Yellow Weatherstrip adhesive or Gorilla Snot.
For Oil Pans or Valve Covers.
Clean metal surface, bang out dents, use minimal amount on metal surface, install Cork Gasket, place pan or valve cover on flat surface with a weight on top. let cure for 12-24 hrs.
Use heavy grease on other side of cork, wipe down to a thin layer with finger, torque in place.
I never use "adhesive" on both sides of a gasket, this may present a problem upon future removal.
Permatex #1 is a sealer, not an adhesive, use on coolant seals only.
Permatex #2 is not much of either, it really only holds the gasket in place till you get it clamped down.
Head Gaskets, whew! time for a fight.
I like spray CopperCoat, I spray both sides twice, let set up for 4+ hrs and use ONLY on Cast Iron to Cast Iron heads.
Aluminum heads on cast blocks require alternative methods.
Head Bolts, use Permatex 242 Blue on the ones suggested by the book to keep oil out of the water, I forget which few bolts they are but it won't hurt to put it on all of them.
Permatex 242 Blue, 271 RED and the othe "retention" grades are "Anerobic" sealers, this means they will only set up in the Absense of oxygen,, you can put it on the bolts, set them on the shelf for a month and still it will work properly, no need to use primer when working with mild steel like engine stuff.
Spend the extra money you have on Brand Name Gaskets and Thermostats, like Stant or Robert Shaw. Many aftermarket thermostats are in generic boxes but inspection reveals made in Tenn by Robert Shaw.
Get to know your parts man at the dealership, a $5 sack of Apples or a box of Dunkin Doghnuts is a good way to get "Jobber" price on your parts. Even if you only need him every year of so, take some by at Christmas time or whenever.. [Bribery, I Know]
I use original GM parts whenever I can afford it, my dealer will tell me which place to get decent stuff when he's too high. [O'Reiley's] Parts from Autozone and Advance seem to have a really high failure rate, especially with ignition wires, rotors, caps, coils, AC compressors and other high end items.
FYI, I never use "New" ignition wires, I drop by salvage yards and pick up handfulls.. GM Service manual says "12-15,000 ohms per ft with a max of 35,000 ohms.
Why pay big bucks for junk when factory wires are really good.
One more item here, unrelated though, of the 200+ guys I've worked around, I get lots of feedback..
Shock Absorbers, factory GM shocks on Full Size Trucks, Yukons and the like seem to never wear out.
Replace them with a Gabriel or Monroe and see if it don't go south in a year or two... Never replace what ain't broke or is fixin to bust