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  1. 75gmck25

    Grounding question

    I did not go back through all the messages, so maybe this has been answered. Did you check the rear harness that runs across under the truck between the taillights, and ensure the ground wire (usually white) in the harness is grounded to the truck frame? Note - I have a Tekonsha T-One...
  2. 75gmck25

    Well that sucks

    The smell of antifreeze is very distinctive, and I assumed most folks would recognize it immediately. Nothing at all like you would smell from an A/C line refrigerant leak.
  3. 75gmck25

    305 small block help???

    A piston stop is cheap, and there are lots of online articles that explain exactly how to use one. You can even make one by drilling out an old spark plug and inserting a bolt. Also remember that GM used a different place to mount the TDC pointer over the years. Sometimes it’s exactly at...
  4. 75gmck25

    Well that sucks

    It definitely looks like you blew a hole in the evaporator (evaporator looks a lot like a heater core). Relatively easy to replace the evaporator, but as was mentioned, once you open it up there are other parts to check and update. - if it’s already R134a, you can probably just replace parts...
  5. 75gmck25

    Grounding question

    IIRC, I think the braided ground from my frame to truck bed was up under the truck near one of the gas tanks. Hard to see and very exposed to road dirt and rust.
  6. 75gmck25

    Fuel line question

    SAE J30R7 (used for TBI or carb pump pressure) and SAE J30R9 (used for EFI high pressure) are the newer specification hoses that will hold up much better when using gas with ethanol. You can also buy EFI hose clamps that are a full-circle design that should tighten down better than standard...
  7. 75gmck25

    Gas tank replacement, 16 gallon

    The point is, who needs to have gas tanks in a matching color? They are tucked under the bed, and the bottom covered by a black shield.
  8. 75gmck25

    Fleetside bed sides different?

    Mine had a dealer-added tank on the drivers side. It was fabricated out of steel plate, and had a drain fitting on the bottom. Filler connected to a hole drilled in the side of the bed. Switch on the dash was a simple DPDT swirch that changed both the tank solenoid for the gas and also the wire...
  9. 75gmck25

    Tank selector

    The old single wire valves move/default to the main tank if they lose power, so it’s always good to keep it at least 1/2 tank in the main. I believe the newer valves have a solenoid inside that stays in its last position, so they should stay on whatever tank you last used.
  10. 75gmck25

    NP203 question

    These trucks always sucked for gas mileage, and folks tried all sorts of fixes to make it better. I’d have to think a little more about running in hi Loc with hubs unlocked, and what it would do. It would be like running an NP205 in 4H and unlocking the front hubs. You would still be driving...
  11. 75gmck25

    Tank selector

    The OP has a ‘77, which probably has the old 6 port solenoid with a single power terminal. These are no longer available. I have been lucky, and so far mine continues to work. You can replace it with the newer Pollak solenoid and dash switch that has a wide multi-terminal electrical plug...
  12. 75gmck25

    NP203 question

    Locked hubs should not be an issue for the NP203. If you leave the hubs locked tfor quite a while it might be a PIA or unlock them if there is dust and dirt in the mechanism, but it sounds like you don’t need to unlock them.
  13. 75gmck25

    New or junkyard?

    The design of the front fenders traps water and various junk (leaves, dirt, etc.) in the bottom, so original fenders usually have significant rust. It sounds like aftermarket may now have improved, but in the past there were many that were poorly made and relatively thin metal
  14. 75gmck25

    Does anyone see a fusible in this pic?

    Since my ‘75 K25 probably matches your ‘75 K20, I think I can help. - the clear fuse holder on the left is the fuse (25 amp?) for the HVAC blower high speed. If it blows you will have no high speed on the blower. On mine the fuse holder melted and I had to splice in a new one. - the black...
  15. 75gmck25

    Edelbrock build

    Stock 1406 usually has quite lean jets and rods. You might have to get a Edelbrock tuning kit and richen it up for a 460. Also try swapping in higher vacuum rated springs if you find it has an off-idle or part throttle bog.
  16. 75gmck25

    1979 454 C10, Factory Air

    I have always used a factory-style accumulator (or filter/drier) in the stock location, but I assume the VA part does the same job. Did you describe your components in slightly the wrong order for the connections? - The compressor has a hose running over to the accumulator, which is then...
  17. 75gmck25

    The new 14 bff full rehab questions and conversation thread

    I don’t even know enough to be dangerous, but I thought that for many GM axles there are two different carriers, based on the ratio. However, I may also be really off in left field. :) I have not read through up this posting, but it looks like it could be very useful...
  18. 75gmck25

    Chevy 14 bolt - gov bomb locker???

    It is called the gov bomb because the locking function uses an internal mechanical design that engages and locks as the axle rpm goes higher. It has been compared to a governor with centrifugal weights. It works fine when you spin the tires up gradually after getting stuck in the mud or snow...
  19. 75gmck25

    Dash pictures of ‘77 K5 Blazet w/tach

    That is great to see there is a replacement board for the original truck tachs! I read the old articles about how make your own repair, but my tach still works (so far), so no need for a fix yet.
  20. 75gmck25

    Dash pictures of ‘77 K5 Blazet w/tach

    GM also had issues with the electric board on the back of their tachs in the 70’s. There are multiple sites with a replacement board for Corvette tachs, but nothing for the squarebody. I’ve also seen articles explaining how to fix the factory board by repairing a circuit trace and replacing...
  21. 75gmck25

    Edelbrock Carb and original Air cleaner

    Edelbrock also sells a banjo fuel fitting and dropped fuel line to get more air cleaner clearance, but I’ve never verified that it works to clear a stock air cleaner. I used the plastic spacer with a 1406 and made it work by carefully placing the air cleaner, but it always seemed kind of...
  22. 75gmck25

    Fuel Smell

    I had the same issue with a crack in my fuel pump spraying fuel sideways onto the exhaust manifold. It was a small amount, and evaporated very quickly, but still gave a strong fuel smell. The original fuel rubber hoses also developed small cracks that were not visible until you bent the...
  23. 75gmck25

    Fusible link?

    Fusible links are always 4 awg sizes smaller than the wire it protects. When I switched to a larger gauge charge wire for my alternator, I believe the one i pulled from a GMT truck was 8 gauge with a 12 gauge fusible link, as compared to my Squarebody 10 gauge wire with a 14 gauge fusible...
  24. 75gmck25

    Fusible link?

    What are you trying to replace? I believe the standard GM fusible link is a 14 gauge link for a 10 gauge wire. You should be able to get one at any parts store. https://www.rockauto.com/en/moreinfo.php?pk=623530 Another good source is any junked GMT400 truck, since the wires and fusible links...
  25. 75gmck25

    Cam shaft

    You said you are “building” a 350, so does that mean you are replacing pistons or making other changes that would increase compression or improve head flow? That 222/222 cam works with a stock low compression engine, but as Ricko1966 said, the low compression heads are a poor match to that cam...

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