Halfbreed - GMC Z71 + IH Extd Cab

[67ChevyRedneck]

Awwwwwwwwww...
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[Palf70Step]

[tecky11]

she looks damn good, is it done now? or ......

[nuke1]

Love those drives also with my dog

[ERASER5]

That's a dog gone cool pic.

[sparkydog]

If you all recall I am trying to finish the integration of the IH and GM cowl/wipers/HVAC sheetmetalfication. Next up on the punch list was to redo the mods to the IH defrost nozzles. On an earlier post I had altered their angle of dangle but used duct tape to seal them off. A member of the IH forum suggested that I should have used fiberglass and it has haunted me ever since. So here's some shots of me glassing up the nozzles and curing them in my oven when the wife wasn't paying attention. I also had to pour some filled resin inside their passageways in order to seal them off.

[sparkydog]

I also (finally) figured out a strategy for how to seal off the inner-most firewall and commenced to fab the patch panels, tack them in place and then seam seal. Some sections of the sealing had to be finger-splooged into place - hence the photos that look like the egg hatchery from Alien.

[sparkydog]

Patch metal for the cowl/firewall in the previous post courtesy of the ex-hood from the 96 GM Xcab.

While I was waiting for the seam seal to cure I wanted to check on the design of the rear bumper brackets. Since I live in SoCal I pretty much instinctively check for Black Widows when I pick something up that has been laying on the ground for awhile - like my rear bumper.

Even so I had a nice adrenalin rush when my brain tried to process the conflicting signals between an expected spider and an un-expected praying mantis. Not that they are dangerous - it's just that for a nano-second it came across as an extremely large, green-widow.

Later that evening the mantis was trying to hump my front tire.

[pickup67man]

Originally Posted by sparkydog

If you all recall I am trying to finish the integration of the IH and GM cowl/wipers/HVAC sheetmetalfication. Next up on the punch list was to redo the mods to the IH defrost nozzles. On an earlier post I had altered their angle of dangle but used duct tape to seal them off. A member of the IH forum suggested that I should have used fiberglass and it has haunted me ever since. So here's some shots of me glassing up the nozzles and curing them in my oven when the wife wasn't paying attention. I also had to pour some filled resin inside their passageways in order to seal them off.

Honey why does dinner taste funny tonight. Were you cooking car parts for lunch again.

By the way I'm in Washington and today was sunny and 65 degrees. Not bad for November.

[Lippyp]

Originally Posted by pickup67man

Honey why does dinner taste funny tonight. Were you cooking car parts for lunch again.

:

This is why I've kept the old oven after our recent kitchen remodel. Its going in my garage so I can use it to powdercoat small parts etc.

[maxxxy]

Originally Posted by sparkydog

So here's some shots of me glassing up the nozzles and curing them in my oven when the wife wasn't paying attention.

Hahaha I cured some paint on some exhaust manifolds in my moms oven when she was out of the house. She got home just in time to see me pulling them out of the oven. Lets just say she wasn't too happy...
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[sparkydog]

These shots are while I was still working to integrate the HVAC gear. The final challenge was how to seal off around the defrost nozzles. This was the only remaining area where cold air from the cowl could infiltrate into the interior. I fabbed up some "blockage" plates and then used some foam.

After that I fabbed up a manifold for the air distribution box and connected the defrost hoses.

I will be using the GMC control panel for the HVAC but it will be hidden from view. I cleaved off the guts of the IH control panel. tack welded the knobs into fixed positions and will be running with this as a false control panel. I left one knob functional and hope to figure out how to use it has the release knob to reveal the hidden GMC controls.

[sparkydog]

I finished applying "FauxMat" to my cab. These are shots of the roof. One thing that I did during all of this was to go around on all of the larger flat sections and apply some extra layers so as to damp out the drum effect of these sections. It works real well. I just knocked on each section, added some material and knocked again. On the roof it took 3 layers because it was so large.

After that it was time to throw the dash back in, throw Sparky the dog in the rear of the cab, pick up one of the Daughters from college and drive to Oregon for Thanksgiving. Chalk up another 1200 miles on the truck!

[tecky11]

wow that looks slick as hell, great job wish i had the balls to do this. altho if you dont mind i would like som shots of how to you ran the HVAC thrru the IH dash

[sparkydog]

Originally Posted by tecky11

wow that looks slick as hell, great job wish i had the balls to do this. altho if you dont mind i would like som shots of how to you ran the HVAC thrru the IH dash

I don't have any more photos beyond what you see in the this build. The top 2-3" of my firewall is IH the rest is GM. The shapes of the firewalls and the cowl walls don't match at all. The GM is squarish and the IH is curvy. If I had slid the IH cab rearwards so that the stock IH fenders were centered over the GM front spindles then then MAYBE the alignment of the dash/cowl/firewalls would have been a little better. The only thing that really needs to come through the upper firewall is the IH defrost nozzles and ducting.

[tecky11]

it looks great, but i do have one more question for ya, were do you get a windshild for that truck?

[sparkydog]

Originally Posted by tecky11

it looks great, but i do have one more question for ya, were do you get a windshild for that truck?

Try doing a search of the forums on either binderplanet.com or justih.org. I seem to recall that there might still be a supplier or two that still stock these windshields. There are also people on those forums that are buying or selling used windshields.

[tecky11]

hmm awsome, i need one for my 72, it has a huge crack down the middle of it

[jb1016]

A lot of custom trucks don't even run wipers; yours are re-engineered for maximum effectiveness. Just another reason to love this build!

[sparkydog]

Getting ready to start my gauge modifications. Santa brought me two of the three Autometer gauges I need. I want a 0-6k tach so I need to buy a marine tach.

To prep for the mod I took out the GM factory gauge cluster and tried to pin out all the wires. I did OK but still have several circuits that are not as EZ to figure out because they all go through the little circuit board instead of direct to the device.

Here are some shots of what a factory cluster looks like if you crack it open. The face of the cluster is held onto the back via the 4-gang posts that are on the back of each of the gauges. So gentle prying is all it takes and boing out it pops.

[sparkydog]

As usual I will break my task into smaller tasks. I will start by migrating the idiot lights for the SES, ABS, Seatbelt, Daytime Run Lights, Batt and Ebrake up into this opening in my overhead console. This will involve surgery to the GM gauge cluster to get the graphics and the light housings off. I also need to pull wire up the back wall of my cab and create connector assys at both ends for these new circuits.

High beam and turn signals will stay on the dash and I will use the IH style bezels for these. The IH dash had a white idiot light for ebrake on and I am going to convert that to blue high beam somehow.

[sparkydog]

I could use some help with the Gear Indicator stuff. Does anyone know if the PRND321 lights in the gauge cluster are driven off separate wires for each gear or does the little circuit board have logic that does this off of a signal from a single wire?

And is the gear position signal sent to these lights from the tranny or from the shift lever on the steering column? Many thanks for your help!

[sparkydog]

Originally Posted by sparkydog

I could use some help with the Gear Indicator stuff. Does anyone know if the PRND321 lights in the gauge cluster are driven off separate wires for each gear or does the little circuit board have logic that does this off of a signal from a single wire?

And is the gear position signal sent to these lights from the tranny or from the shift lever on the steering column? Many thanks for your help!

Thanks to Google and a little extra patience on my part I think I found the correct schematic and learned what all the circuits into the cluster are. The gear indicator LED's are 5 separate signals coming from the transmission.

[hgs_notes]

You don't ever seem to take the easy way through a project do you? Good luck getting this all figured out.

[Palf70Step]

Glad you found it. I was still having my eyeballs roll around at the whole mess.