Slant Six has No power. will not accelerate
Owned my 68 Valiant for almost a month now.
Sometimes a "shotgun" approach is actually a pretty good idea. If I had just bought this, I would do a "stem to stern" engine diagnostics
Get yourself a factory service manual. You can download one, free, right here:
http://www.forabodiesonly.com/mopar/showthread.php?p=1970088617
1...Check the engine condition.
Pull the valve cover and inspect for sludge. Adjust the valves. Run both a compression and a leakdown test. In this day and age, where may O'Reallys parts stores have tools to loan, and where Horrid Freight is so cheap, and where you can find info on the internet on building your own leakdown tester, there is no excuse to NOT have and obtain some diagnostic gear
If the compression doesn't seem too bad, and the plugs are not showing signs of oil fouling...........
give it a good ignition tune--up. Unless it has been recently replaced, replace the points / condenser if it still has them, rotor, cap, wires, plugs. Set the timing, and if anything, lean towards some "before" TDC.
Got to garage sales, craigslist, and get a tach/ dwell meter and timing light.
2....Fuel system. Replace both hoses, one at the tank, one at the pump inlet in the fuel line. Refer to the service manual and check fuel pump capacity. Replace the fuel filter and any other questionable components, and keep in the back of your mind that the tank filter an be gummed up. consider cleaning or having cleaned, or replacing the carburetor. Many times you can tell by the accelerator pump working or not, and the way the idle screw adjusts
3....Charging system. Check running voltage, check condition of brushes, check belt(s) for condition and tightness / slippage. READ this article on the problems with wiring in these old cars. Even if you do not perform this modification it gives you insight into what you might expect.
http://www.madelectrical.com/electricaltech/amp-gauges.shtml
More here
http://www.madelectrical.com/electrical-tech.shtml