Re: Why does my car have a hard time going up hills?
If the car was purchased out in CO it probably has the "altitude" tune. The big thing they also did for "altitude" was change the standard rear gear from 2.56's to 3.23's. If it is not an "altitude" car you are a step down already. A tach would help there to determine what you have.
I agree manually downshifting to 2nd when climbing would help but if the car was at WOT it should have downshifted by itself to 2nd.
The cheapest thing you can do for the car right now is to do a recurve of the distributer for a few $$. Check out Larry's guide on how to do it on this board. It will work just as well for your setup.
You should have an HEI so you will need one of those kits. You can get one at any decent auto parts store. If you are at 60 mph with 2.56's that is only about 2000 rpm. In 2nd gear that is about 3000 rpm. (2500/3750 w/3.23's)Your stock 105 HP peaks at an astounding 3400. Your distributer probably only gets full advance at 5000 rpm the way GM did it.
If you can't get a kit what you can do is pop the distributer cap and rotor off and just remove one of the springs. Leave the weight on. That will quicken up the curve a bit. If you get a kit just use the springs they supply which are lighter than the factory ones. The weights they give with the HEI kits are usually screwy. If all your timing is in by 3000 rpm you may just pick up a few ponies right where you need it on the mountains.
Add a few degrees to the factory initial timing and you'll be ok if you can't measure total. Keep an ear out for pinging especially at WOT but you should be ok at that altitude.
Flip over your air cleaner lid. Make sure your air filter is good. That engine needs every bit of cool air it can get.
If your car still has a catalytic converter get rid of it. If you can just replace it with a piece of pipe. If you have to have one for emissions just get a cheap universal replacement. That original one was restrictive when it was new and by now it is probably clogged good.
I know when I was out that way a few times some of those interstates out there are pretty exciting. Mountains out there are way different that mountains in the East. That one outside of Denver, I believe, where it looks like a 10 lane version of a water slide. I couldn't believe how steep it was. I was nervous about my brakes. Forget about it in the winter.
1976 Century 455
NE GSGN #29
Texas Mile 164.4 MPH