sluggish power

[Mv7fd]

my 79 k20 has a 350 with a 4 speed manual np205 transfer case and 4.10 gears and it just seems like it does t have much power. the brakes aren't hanging up or anything. should these trucks make a lot of power or am i just thinking crazy

[MountainGoat1966]

How many miles are on the engine?
It could be tune-up related, IE: carb or timing.
It could be a stretched timing chain.

[Chevy3+3]

Does it have a 4 barrel carb? If so the seconday's may not be opening. That would cause it to feel sluggish when you step on it. Even an average 350 should feel like its got some go with a 4 speed and 4.10 gears. Also check and make sure you vacuum advance is working properly. That would make a difference also

[frank69]

Hey mountaingoat where are u from in n az

[Mv7fd]

It has 100 thousand on the motor I've done the general tune up and I know the secondaries work how would I check if the vacuum advance works

[donut]

Couple easy ways. Start the truck, pull the vacuum line off the vacuum can and put your thumb over the line (don't want massive vacuum leak). Did the idle change? Yes, it's working. No, it's toast or the line is not supplying vacuum.

You can do the same thing with a timing light. If the truck wasn't running, you could unplug the vacuum line, throw a couple foot length on the vacuum can, and use lung power. Of course, pull the dist. cap so you can see if the can moves anything.

100k mi and 35 yrs old, I really wouldn't expect the timing chain to be in prime condition.
To do a rough check of this, I pop a valve cover and turn the crank a little. Little forward, little back and watch how much slop there is before you see any movement in the valvetrain.

If you really want to get crazy, you can do a compression/ leakdown test and see the condition of the cylinders.

When you did the general tune, did you use the factory timing specs or did it get advanced more?

[MountainGoat1966]

Originally Posted by frank69

Hey mountaingoat where are u from in n az

I'm in Ash Fork.

[Chevy3+3]

I'm not sure what your working with but there is usually a vacuum port fitting screwed into the back passenger side of the intake. Its not uncommon for the vacuum lines to get brittle and break there or simply fall off. Or the vacuum line could have fallen off of the distributed. Either of those could keep the vacuum advance from working.

I'm not saying its a vacuum advance problem but its definitely one of the easiest and less intrusive things to check. Start simple first. Also make sure your timing is correct. It won't hurt to have it advanced some. It should perk it up a little

[cadillac_al]

I have never drove a chevy 350 with a stock cam since they were new in the 70's. They are always worn out or already replaced when I get them. If yours hasn't been replaced yet then it must be due. The stock cams are pretty small anyway.

[donut]

Oh, forgot to mention, these motors were NOT powerhouses. They usually did an adequate job for what they were. Think work truck, not sports car.