[oil pan 4]

It looks like my big block engine has suffered a leaking head gasket due to overheating.

First do a post mortem on the heads to see if my lean burn carb tune was burning the exhaust valves. Just need to find my valve spring tool or buy another one, last time I used it was when I put together the diesel in 2009.
From what I can see I don't expect them to be burned.

So to fix this I am going to do a few efficiency up grades.
The #4 cylinder has had coolant leaking into it to for months maybe and had developed a nice cylinder taper. To remove the worn cylinder taper I will have the cylinders bored 0.03'' over (4.28 inches).
This means new pistons will be needed, going with hypereutectic alloy speedpro dome pistons to increase compression to about 11.1:1 with a 100cc head.
Then do file fitted rings since it worked so well for my diesel, with slightly reduced tension oil rings. (the diesel runs ultra low tension oil rings, cant do that on a gas motor)
Then have the block deck milled the minimum needed if its not perfectly flat.

The engine had a bit of a knock that had been going away, possibly due to cooler temperatures and thicker oil. I have never seen nor heard of a lower end knock "get better" or go away on its own.
So its going to likely need a new crank and at least a new rod or 2, if its not being caused by a piston.
I would like to reuse the connecting rods because the forged OE 80s truck rods are pretty tough, surviving in blown, nitroused or alcohol motors with out issues.
New crank will be a internal balance 4.25 inch stroked cast steel crank.

A problem with continuing to run OE style flat tappet cam shafts is the government mandating ever lower levels of anti-ware additives. To prevent grinding a lobe off the cam I will just go on ahead and upgrade it to a hydraulic roller cam, with appropriate roller lifters and put on roller rockers. Then I can run any government mandated additive depleted SM or SN rated oil on the shelf at walmart.

The edelbrock 650 carb was on the ragged edge of being able to support this motor. It would go really lean, as in off the scale, greater than an 18:1 a/f at WOT after several seconds. But its what I had and knew how to tune so that is what I used. I am going to go with a edelbrock 800 carb so I don't starve the engine for fuel.

Edit: when I took the motor apart I pulled the exhaust valves and they showed no signs of burning. So my lean burn tune is safe.