Top/Bottom End Alignment
 

Any easy way to get the timing reset on the Top end/Valves without taking the Valve cover off on a 4.3L Vortec? or am i doomed to remove it anyways and buy new gaskets (for both covers just for the sake of preventive maintenance)

And has anyone else had constant fuelpump failures on a 1999 S10 with the 4.3L Vortec?

I really don't understand your question. There is no valve lash adjustment on a 99 S10 4.3 V-6, if that is what you are asking about. You will need to explain what you are asking about a lot better. You are not making any sense.

Not quite, Last person who worked on this motor threw the timing all out of whack (rotated the crankshaft around independent of the cam without actually knowing what they were doing) threw the chain on and called it done, it does not run anywhere near correctly. Does the 4.3 not have a Camshaft or something? i've not worked on this type of motor specifically, but it cant be that far removed from normal.

It is a normal engine - now that its a little better explained if the timing chain marks were misslined then engine buttoned up.
It isn't as simple as removing valve covers you get the joys of stripping down the front of the engine to the timing chain and starting over.
Fan shroud, maybe radiator for clearance, belts, fan, water pump, vibration damp, timing cover, prob alternator, power steering pump ect .....

There are no timing marks or valve timing adjustments accessible by removing valve covers as you described. This engine does not have a camshaft located in each of the heads as is popular with some modern engines, especially imports. It has a single timing chain with a camshaft in the center of the engine and pushrods/rockers to operate the valves. Just check the cranking compression. If the timing chain is not on the correct mark, the compression will be low on all cylinders. If it's around 125# or higher, you can assume the camshaft is timed correctly.

Ah, all of that save for the Alternator, Steering Pump, etc, have all been removed a long time ago, its been sitting the garage for several years like that now. And im going to assume i need to remove the valvecover if the pump and alternator are coming out (what with being right over the top of it). And just to be sure i dont botch it - Exhaust valve full open with #1 At Top Dead Center?

You could remove valve covers just for peace of mind - as les stated above its a single cam engine so every thing as far as crank/cam alignment is all done under the timing cover on the front of the engine - you might remove spark plugs also to ease in turning cam and crank for alignment - don't get carried away rotating such and bend a valve - if it was made to try and run hopefully it didn't slap a valve or two into a piston and bend them .....

So as long as the marks are aligned while the #1 is at TDC it will all be set?

Do a internet search for the year of the motor and how the marks align and set them as shown
{ lets say 1999 Chevy 4.3 timing marks and it should bring up several hits }
The dist maybe off some too and need to be reset as it would have been set up with things off

Alright, thanks.