Proper use of gaskets and sealant in any engine is based on how well the engine is machined and what kind of pressure the gaskets are to be subjected to. Two machined surfaces seal best when a paper gasket is used, clean and dry. Pontiacs are a little "nicer" than a lot of other American V8s of the era regarding "fit and finish". The factory went the "extra distance" for sealing surfaces and techniques.
On the other hand, Pontiacs are also known for high crankcase pressure, particularly under racing conditions. This puts added stress on the gaskets and seals.
Specialty and performance gaskets are made and used differently than "stock" gaskets. The manufacturer's recommendations should be followed when using them. The subject here is more related to stock-type gaskets. It is assumed the parts are clean and free of damage that would prevent a good seal. Never use a "ScotchBrite" pad on a power machine to remove old gaskets. It "rounds" corners and can ruin aluminum parts. An old fashioned scraper and a sanding block are best.
The two sealants required are Permatex "Ultra black" RTV and Permatex "Aviation" (small bottle w/brush).
The procedure for the rear main seal is well documented and all the "good" seals come with step-by-steps in each package.
This is the order of final assembly used at CVMS, starting with a finished short block.
Timing cover is installed using only the gasket. No sealant. If there are significant pits around the water inlets on the block, a very thin "smear" of RTV or coat of Aviation is okay on the block side. Use a torque wrench in an alternating pattern, 28-32 lb-ft. The timing cover must be flat and free of corrosion around the water inlets. Use the top bolts that go through the water pump for alignment only at this point. No need to tighten them yet. The pan is the fun part. If using the stock 4-piece gasket, the cork strip is the best bet for the rear lip. Curl it up in a paint can cap, making sure the chamfered ends are angled "in". Set it aside while you're assembling your short block. That will make it contour properly around the main cap. For the later blocks with groove cut in the cap, a piece of 3/16" thick cork material (available anywhere) cut to length is better than either of the rubber lips used on them. Felpro rail gaskets are cork. Victor/Reinz are paper. The rails have blue alignment rings for each side. The cork must have them or it will "squish out". The paper doesn't seem to have the problem.
Lay a 1/8" bead of RTV over the cap, contiguous, with a "dab" on the flat area where the cap meets the block. If grooved, the RTV should be centered in the groove. If flat, the bead should be about 1/2" "in" from the rear of the cap. Use the rail gasket as a template. Place the strip in the groove or over the bead and lay the pan over it. Install the two bolts next to the cap and "finger tighten" them. Let it set for at least an hour. Longer is better.
Remove the pan. Some test-fitting of the rail gaskets in relation to the strip should be done. Some trimming has been known to be necessary. Lay a bead over the center of the strip with "loops" around the first bolt holes on each side. Some trimming may also be necessary on the front "lip" gasket. Add a 1/2" long dab at the point where the timing cover, block and pan all come together, across the rail to the lip. Allow it to set up a bit, just a few minutes so it developed a "skin" on the RTV. Lay the rail gaskets in place along with the lip gasket. Add another bead around the rear-most bolt holes, joining the bead already on the cork strip, and another 1/2" long bead where the rails and lip gasket come together. Let it "skin up". Ease the pan into place without a lot of sliding around. Watch the rear bolt holes for alignment. Be careful manipulating a baffled pan around the oil pump so you don't mess up the RTV. Start the rear four bolts first. Use the pan reinforcement tabs available. Next are the last two toward the front, at the end of each rail. Lightly turn them alternating front to back. Once the pan is far enough down to align the four bolts in the timing cover, start them and the other rail bolts. Tighten them to no more than 12 ft. lbs. "Just right" might be a better description, as the gasket can have a mind of its own.... After it has set for a few hours, "snug" the bolts again. Always watch to make sure the gaskets aren't squeezing out. A little is okay. A lot is NOT better. Sometimes the front portion of the pan is not quite right. In that case, a thin bead of RTV can be used between the gasket and the pan, not the gasket and timing cover.
The water pump should be clean and dry. No sealer is necessary between the pump and the plate or the plate and the timing cover. The mounting face on the cover can be flattened out easily on a large belt sander. Only in an emergency, should you use a badly pitted cover and "fill it in" with RTV. JB Weld or other epoxy, or a good welder, can repair a damaged cover. The bolts are tightened to 18 lb-ft. in a "star" pattern.
Head gaskets should be installed clean and dry. For Felpro, Victor/Reinz, NAPA (any fiber material "sandwich") no "retorque" is called for. For higher compression engines, it couldn't hurt! A drop of oil on the threads of the bolts and 95 lb. ft. Shim-type head gaskets are still around and are fine. They require a coat of "High Tack" or "Sure Tack", KopperKote, any of the spray gasket coatings. Paint is not recommended. Retorque is recommended, but I've seen plenty that didn't and lived long lives.
The valley cover gets a 1/8" bead of RTV all the way around. Set the gasket in place and let it "sit" for at least 30 minutes. No sealant on the block side, set the cover in place and locate the holes ("start" the bolts). Ideally, two rubberized washers are used on the valley cover bolts. If not available, a 1/8" bead of RTV around the hole, a 5/16 flat washer and, a bead under the bolt head, and it will seal nicely. Tighten them lightly in to or three steps over about 30 minutes. DO NOT over-tighten, as that "pulls" the cover inward. Care must be taken to NOT "bottom" the bolts in the holes, as that binds the cam bearing. A new PCV valve grommet is called for.
Intake manifold gaskets use orange alignment rings to hold them in place. If there's pitting around the water holes in the heads, a coat of Aviation on the head is okay. Nothing on the manifold. No sealer around any of the ports. Start all the bolts. Snug the front ones over the water ports but don't tighten them. Tighten the draw-bolt from the timing cover. 18 lb-ft.. should do it, but be careful. Beginning in the center, snug all the bolts. Tighten the front two at 28 lb. ft. Starting in the middle and working your way out, tighten the rest to 28 lb-ft. Thermostat housing bolts are 28 lb. ft. Again, only of there's significant pitting around the hole, a coat of Aviation on the thermostat housing flange is okay. If the housing itself is pitted, replace it.
For stock applications where the valve covers won't be coming off often, the cork gaskets are called for. No sealer is necessary if the covers are in good condition. Cars raced or driven hard are more likely to need maintainence there. For solid-lifter hot rods or racers, the "rubber" gaskets are more popular, as they're more capable of surviving repeated removal. It'spopular to "glue" the gaskets to the covers. RTV works well, but weather stripping adhesive is also popular. Over-tightening the bolts is the main cause for gasket failure here. Regardless of torque "specs", one must find the "happy spot" for the cover and bolt combination. For more clearance over the rocker arms, Felpro provides a 1/4" thick valve cover gasket. The stock bolts aren't long enough for use with those gaskets.
The distributor and fuel pump use no sealer. The 5/16 bolts torque to 18 lb. ft. The 3/8 bolts torque to 28 lb-ft. for the fuel pump. The distributor clamp should be tight enough to prevent the distributor from turning.
Following this will get you a clean assembly without sealer oozing out anywhere, and will prevent unwanted "chunks" of sealant getting into the oil pump, a common point of catastrophic failure.
Lastly, the philosophy of "if a little is good, a lot is better" does not apply. If a little is enough, a little is enough! --Jim Lehart, Central Virginia Machine Service