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That's what I'm talking about! Nice
I think I am just going to leave it alone for now. If I get headers I am going to fit them, take them back off, the wrap them and reinstall. And use dead soft copper gaskets.
Sorry about being late to the thread. I almost commented last night, but didn't realize you were looking for general economy advice as well.
On the exhaust note. This the above quote is what to do, and what I have, or pretty close. Stock manifolds, stock down pipes, to high flow cat, 3" mid-pipe, single high flow muffler (note high flow does not have to be loud!), so in my case I picked a large oval muffler, with dual 2" outlets both exiting on the D/S. If you go dual, a cross over pipe is required. I large single is cheaper, and better mannered.
If you want advice on stuff to help you out in the mileage department and cheap enough to pay for itself I give my 2 cents. First you gotta think about how long it'll take to pay for itself, if your only doing it for mileage. Obvious make sure the carb isn't running rich. You should have a properly functioning heat riser and thermac, those work together in part to allow a lean or quicker choke pull off reducing the amount of time the choke is on will help your mileage, unless you only start it cold once or twice a week you.
Manifolds in '87 didn't have the ports for the air injection off the smog pump??? What years had the air injection system?
The best way is to look at vacuum diagrams and set up the EGR valve the way the factory had it, but if there are check valves missing or the thermoswitch is inop, you can connect the EGR vacuum hose to ported vacuum. The problem with that is that the EGR will open when the engine is cold, which might lead to a little hesitation or bogging when it's cold and EGR comes on. However, it takes about 5 minutes to connect it directly to ported and I've done this both on personal vehicles and customer cars and in practice it worked out fine. Also before you do that it would be worth while to warm the truck up and apply vacuum to valve and see if the engine stumbles or stalls. If it does then the valve is working and your good to hook it up, if not you'll need to figure out if the valve is bad or if there is a clogged passage in the block. A fact that a lot of folks don't know is the EGR valve, also lowers NOx emissions in the exhaust. NOx is not nearly as bad for the environment as other gasses, but it is very good at damaging lung tissue. I'm not trying to be a tree hugger and exhaust is still bad for you even with an EGR valve I'm just mentioning this as often folks are not aware.
By ported vacuum you mean timed vacuum and not manifold vacuum correct? Time permitting I will get the Mytivac out and see if the valve is working. My heat riser is connected, not sure if the flapperdoodle (thermac?) is functioning properly. How can I test that? Just observe? I do know that it starts right up on the first turn of the key even in single digits and runs very well under all conditions even if it is down on power compared to older V8s I have owned. My 20+ years working on old Porsches didn't prep me for troubleshooting GM emissions systems. Could you possibly give me a basic idea of how the EGR system works? I appreciate your help.
