If you are interested in the value of the car then it would be best to stay stock. Any modifications will bring the price down. I own a 1970 Chevelle SS 396 convertible that I was offered $130,000.00 for it last night. It is all original so you determine what you want. Me, I prefer the price, and no I am not selling at this point.
replace or rebuild engine, its kaput!
You should always replace the timing chain, tensioners and sprockets whenever you rebuild the engine.
Rebuild!!!! There is no need to replace the whole engine. The head gasket is a pretty easy fix if for a machanic. You will save a lot of money this way to. Your looking to spend between $400-$700 depending on who you have do it.
balls?
both good engines but i have 65 elcamio with a 454 and it is just the best engine i have ever put into a chev. i would go with a 454
Timing chains are designed to last the life of the engine and are normally replaced during a complete engine rebuild. Unless it gets noisy there is no need to replace it.
Any time you rebuild the engine you should always put in a new timing chain. They are far more durable than a timing belt.
You have to replace the piston rings and/ or the piston. Once you take the cylinder off, you should make sure nothing falls into the bottom end of the engine. If you are not familiar with this, then you should consult a mechanic.
It would be far cheaper to replace it with a used one than to rebuild the existing one.
A water pump should have nothing to do with the bearing in your engine. If you are hearing a knocking from the engine then you are going to need to replace/rebuild. I have seen bad waterpumps make knocking nosies but you said it was new. Id check your work!
To rebuild a snowmobile engine the cost of rebuilding will depend on the internal damage(s) or what it needs. To get a fair assessment the engine should be torn down first so that parts can be inspected.
about $1,800