Looking back now, I should have known that the hole in the floor board was not going to fly… So that is the task for this week. Getting that hole covered up so that it will pass inspection. I have been assured that, when fixed, it will pass.

The headers fit very well, however, the mandrel bent exhaust system did not fit to my liking.  The passenger side exhaust pipe needed to be cut into 4 separate pieces to properly clear the frame & transfer case as well as have the pipe end up at the proper place to tuck the mufflers up under the truck.  The driver side pipe only needed to be cut once.

I have the driver side pipe welded back together with the appropriate clearance and positioning for the muffler.  I also fabricated a hanger to properly locate the exhaust system using some 1/4” bar stock and an exhaust isolator from NAPA.  I will have pictures of these pipes up at some point.

Here is a short video of the open headers:

Enjoy!

I was able to get a set of Hooker headers for $146 delivered next day from Amazon.com.  The headers and the exhaust system I have purchased are made to work with each other nicely.  However, not as nice as a true bolt in.  Some "massaging" of the exhaust will be necessary to get the mufflers and tail pipes located where I want them. Nothing a cutoff wheel and a welder will not fix.

The good news is that I was able to save the Flowmaster Series 40 mufflers that were on the truck and they will get welded back into the system.  I am trying to find some high temp cold galvanizing paint locally right now so I can spray down the welds to try and prohibit rust formation.

I also did some more digging into the speedometer calibration and what needed to be done.  I pulled the driven gear out of the back of the transfer case and had a look at it.  It has a 7 tooth drive gear and a 19 tooth driven gear. I would need to step up to a 23 tooth driven gear to get the speedo to read right.  However, only up to a 21 tooth gear is available.  So I will need to purchase an add-on unit (speedometer ratio adapter) to get to the proper ratio.

I have pictures of all of this stuff, but will have to update later.

I did notice that the speedometer is noticeably off.  I am assuming that the gear ratio is left unchanged and since the original tires for this truck were H78-15B which had around a 27.8″ outside diameter, the speedometer is off by ~20%.  This was using the information on the following websites:

NovaResource.org – Speedo & ChevelleEngineer – Speedo

My next task before I actually put this truck on the road is to patch the hole in the bed floor which at this point in time will just include some silicon sealer and sheet metal screws.  I will also have to get the exhaust so it exits out behind the rear wheels to pass an inspection.  I am not sure if I am going to slap on the headers just yet as the temps outside have been quite frigged and I will need the cooperation of the weather to get it done.  Time will tell.

I took the Blazer for a spin down to the tire/exhaust shop at the end of the road to have them give me an idea of how much it would cost to have an exhaust system installed.  They use heavy pipe for their exhaust systems and bend it up right there, but they are quite expensive.

On that drive, I still had a pronounced bog at initial throttle opening.  WOT was good and it revved freely with greater throttle.  I have found several references for tuning the Rochester Quadrajet carb and all signs point to a malfunctioning accelerator pump.  I will be pulling the carb again soon and will likely be fully rebuilding it.

I definitely need to get the exhaust fixed up and then move on to tuning things up.  It is difficult to hear what is actually going on with the motor when the exhaust is leaking out of several places! 

Several local and online retailers have a performance dual exhaust system that would bolt up to the headers so I will likely be going with that arrangement.