TCS Emissions

[74beachtruck]

Hello, to the knowledgable ones, from Virginia. I have a '74 K-10 w/350 and 3-speed on column, full time NP203 with 95,000 miles on all original engine/drivetrain. Have not seen hardly any with this set up so don't know if not many survived or my granddad special ordered this when he bought it new in '74. Anyway, just finished a resto but have always thought it could run a lot better than it sometimes does. First, it is very cold natured and until very warmed up it wants to do a lot of "bucking" especially in the higher gears. Also, is very slow to accelerate once shifted into high gear. Has better acceleration from about 45 or 50 mph once applied. Second, it always starts good but sometimes is not consistent with the idle upon warm up. Recently, it will sometimes sound as if it wants to cut off unless you feather the pedal and the idle will catch. Also exhaust is smelling very rich. Was wondering if all of this had to do with the TCS that controls the vacuum advance or a number of issues going on? Have replaced just about every component of TCS system except transmission switch(which is working)and vacuum advance unit itself. Points and timing were set not too long ago. Qjet replaced not too long ago along with all new vacuum lines. Fuel pump and filter replaced recently. I am thinking about converting to EI as I think this might help or cure a lot of these issues. If so, could all of the TCS components be disconnected? Any and all advice is much appreciated. Would like to keep ignition original if possible but don't know if it would be more trouble than it would be worth. Thanks a lot!

[LTZ C20]

Can't really help you with the TCS emissions questions but I can recommend that a you convert it to HEI ignition. Points is now very inferior and no where near as reliable as HEI. Which is why vehicles that came with HEI originally can still run strong strong 20-30 years later. If you want to keep it original. You can buy reproduction replacement HEI parts for these trucks because in 1976 GM started using HEI on the production line. If you do the conversion right, it will look and function all factory and you can use GM AC Delco parts.

[74beachtruck]

Thanks for that, LTZ C20. Hindsight being 20/20, could have kept the HEI off of the '76 donor truck that I used to resto mine but ended up selling it along with the motor. I didn't know about the reproduction HEI parts just the Mallory,etc. and will look into that. I think the HEI will make a major difference if there is not some other issues going on. Thank you for your time!

[LTZ C20]

Your welcome. The points systems are just point-less these days. Pun intended. You will be much better off with HEI. You should still be able to get a distributor, plug wires, spark plugs, coil, cap and rotor from a dealer. The rotor, cap and coil should come with a new distributor assembly. Then all you will need I think is a reproduction HEI harness.

[frotosride]

You could also retain all of your stock parts and upgrade to an electronic ignition. It's a simple project that only takes about 2 hours if you've never done one. Best part is no one would know

[LTZ C20]

You could also retain all of your stock parts and upgrade to an electronic ignition. It's a simple project that only takes about 2 hours if you've never done one. Best part is no one would know

HEI would be pretty close to equivalent of this. HEI is an electronic ignition system. Granted it's not exactly the same but if it was me, I would pick the entire HEI system.

[blazer74]

HEI conversion eventually or first, bypass the spark control, connect dist vac directly to manifold vac, may have to adjust idle speed.
Basic tune up.
Current dist check vac can holds vac and advances timing. Point gap setting.
Set your static timing to 8-10 deg.

[74beachtruck]

Thanks again to all of the posters who have offered their input/opinions. I think, before I do anything, I may, as blazer74 suggested, bypass the TCS garbage and run the vacuum advance line(which currently runs to TCS solenoid) directly to vacuum on carb and see if any of the issues clear up. I guess, if anything else, it would tell me if TCS components are adding to the issues or not. Also, I have seen the EI systems that are basically just a module that replaces the points plate inside the distributor with a couple of wires and also the entire distributor cap/shaft systems. With the modules I hear they recommend upgrading coil and maybe even replacing shaft if it has a lot of wear. As far as performance, are these two systems identical, where one just helps you maintain a stock appearance? Thanks and trying to figure out how to post some pics but it is saying the file size is too big. Anyway, a good day to everybody!

[LTZ C20]

On EI conversion provides and electronic system to modernize your ignition by replacing the points systems inside the distributor. Yes it looks factory, but HEI looks factory also because it has been used factory since 1976. Plus if your distributor is original, it could be worn and have end play. In which case an entire HEI distributor assembly might not be a bad idea. That is something that will need to be checked tho. I think overall HEI is a higher level performance upgrade but not in the sense of hot rod go fast performance but instead everyday reliability and overall performance. Plus the spark it provides is more powerful and thus more efficient.

[74beachtruck]

Thanks again, LTZ C20. I will, more than likely, go with the entire HEI system when I decide to do the conversion and if it doesn't look quite as stock as the other, so be it. I think that would be a more dependable system than the points plate swap. Soon, I will be finding somewhere, if I can, to go over the engine and carb to make sure everything is sound and maybe do some tweeking if necessary. When I was replacing a lot of the former mentioned, the EGR valve(which I think was original to the truck)was solid plugged with carbon down in the intake manifold so I don't what condition internally that is in. I don't think it was ever run over 55 mph before I got it a couple of years ago. Having said all of this, at idle it runs as quiet as a church mouse. Anyway, whoever does this I will have convert the ignition system. This, I hope, should complete the mechanical end of the resto.

[LTZ C20]

Your very welcome. As long as the conversion is done properly, it should look factory as I mentioned earlier it is.