Engine lack of power

It starts right up and seems to idle OK, but maybe a little low after it warms up. 1,2 and 3 seem to be good on acceleration but in 4th it seems to not want to go. I can give it gas but no acceleration. In neutral it seems to rev OK when you push on the accelerator.Any suggestions? Thanks.

Are you sure you're getting spark on all four cylinders? It sounds like it's running on three.

Hey j.p., are you up to date on your 3000 mile service interval? I found that my VS would give me all kinds of grief if I didn't keep it properly maintained. I followed the procedures as they are laid out in the John Muir book and that seemed to keep in running fine.

I would do the following things as a routine when I hit the interval:
1. Oil Change and screen cleaning with oil hot
2. Next day....engine cold....adjust valves
3. New Bosch plugs
4. New rotor cap
5. check timing

The (single) carb ususlly did not require any adjustment and I had installed a Pertronix ignitor, so there were no points to adjust. These are pretty straight forward procedures but they need to be done at regular intervals. My worst problem after I purchased the car was apparently due to a bad distributor cap, so that's the reason I elected to replace each maintenance cycle. Not a biggie, they're cheap.

If you are in fact up to date with your service, I'm sure we can dig deeper to diagnose the problem.
Hoss

...performance could also be adversely affected if hand-laid or chopped-gun method was used on your car's body! LOL

Now that's funny Jim!

Dual carbs? One out of synch, jet cloughed or vacuum air leak.
Have you done a valve adjustment and compression check? Too tight, burned or stretching stem.
Looked at spark plugs? One black (#4) and other three light brownish?

Old gas can cause those symptoms also. If the gas has sat in the tank for some months, put some fresh hi test in and try it. This gas now days doesn't age well it seems......

I'll do the tuneup route and gas first. Let you know. Thanks.