'99 tahoa 350, spark will not advance beyond 20 degree's

99 percent of the time this is because you are without fuel or spark. car is almost 20 years old so anything and everything is well beyond its designed life. Pull a spark plug out, connect it to its wire and lay it on the engine block and have someone turn engine over a few times. If you see a spark on the tip of the plug, then you have spark and you should look to fuel supply issues. if fuel injected look to the pressure regulator or fuel pump or bad injectors. if carburetor type look at fuel pump.

Not sure if the 95 is the same as the 93. On the '93 there is a timing advance wire you have to unplug (brown wire near the distributor on the firewall with a plug connector.) Start it up with the wire unplugged and set timing to 0 degrees BTDC. Turn off engine. Plug wire back in and computer takes over. There should be a sticker on the radiator shroud that gives timing and spark gap settings.

Check the front universal joint. These don't have grease fittings and tend to fail
Put vehicle in park and check drive shaft for excessive movement by rotating it
by hand. If you feel any play at all it may have failed. Hope this helps.

Make sure u have vacuum coming from the vac advance hose

Sounds like the timing is off or something wasn't synch'd up correctly during the rebuild. Check the timing and make sure the vacuum lines are connected correctly, especially the vacuum advance which advances your timing when the engine RPM's are increased. Start your timing at 5 degrees before top dead center, the 5 mark on your timing marks, this is the most common baseline setting for timing. If you have to set it advanced beyond 10 degree or retarded beyond 0 then your timing chain was not aligned correctly between the Pistons and the Valves or cam shaft.

Is the engine running hot or overheating? This could cause that to happen. If it's not running hot check your timing. If the timing is on time try advancing it 1 or 2 degrees. Somwtimes slack in the chain from wear will put it off time. Hope this helps.

The timing chain is not that fine, nor do you care about advance with the chain. A single link on the chain is more like 15 degrees, and you will have no trouble deciding which is the best fit.
TDC is always 0, and never 4 degrees advanced.
It is the ignition that is advanced, not the chain. To advance the breathing you would need to either change the cam, or get a variable chain sprocket. But again, you can not tell 4 degrees when putting a chain on. It changes that much at least when you take the slack out.

You can set the timing but the ecm, engine control module will reset it back to specs. So it useless to try. Good luck dont forget to rate

They have this listed under a 2007 E-350 but I new it couldn't be. Any how the torque specs are as follows. The big bolts 1-26 are to be torqued first they are torqued to 120 ft. lbs. then rechecked to 120 ft. lbs. Then tightened 1/4 turn or 90 degrees. After that that loosen all the bolts up till the washers are loose again then perform the exact sequence all over again. After that tighten the small bolts on the outside part of the cylinder head all 7 of them to 20 ft. lbs. Good luck.

after connecting your wire try resetting your distributor or pull timing chain cover and ckeck timing marks on gears