Recent content by 75gmck25

  1. 75gmck25

    AC redo after sitting disconnected for a long time

    Are all the hoses still connected? Any idea why it quite working? Do you know what refrigerant and oil was used the last time it was working? Most folks convert to R134a and PAG oil, since it’s what all stores carry. However, R12 (Freon) and mineral oil are still available. I have used a...
  2. 75gmck25

    hei vacuum advance stop plate

    Base timing on a stock SBC was usually set to about 4-8 degrees BTDC (measured at about 650 rpm idle, vacuum advance line disconnected and plugged). You can get more performance from a stock engine by setting it to about 12, and maybe even a little higher. I have used up to about 15 BTDC with...
  3. 75gmck25

    AC control vacuum lines

    They usually sell it at the parts store in two sizes - GM hard vacuum line. You can splice it with small sections of rubber vacuum line. Dorman 47419 or 47417...
  4. 75gmck25

    dash pad

    Sounds like Chevy used the same color scheme as my ‘75 GMC. Interior color is mostly saddle (tan), but the dash pad is dark brown.
  5. 75gmck25

    Problematic Starting - rotate crank before starter engages?

    Also make sure it’s installed with real Chevy starter bolts. They have a knurled section that helps everything to align properly. Similar length bolts might fit, but don’t keep the right alignment.
  6. 75gmck25

    Unable to identify steering column piece

    They sell replacements in a kit to repair a GM ignition rack. Check yours carefully for cracks, and replace it if any part of it seems weak. It’s a common breakage item in the column. If the rack does not move the rod correctly, the key will turn but will not slide the ignition switch...
  7. 75gmck25

    No Defrost

    You can use a hand vacuum pump to pull vacuum on the actuator and see if it works. If it still works, then it’s probably the lines to the controls. Do the rest of the actuators work when you change hvac positions. For example, if you put it in max a/c you should see the flap open in the...
  8. 75gmck25

    Belt squeal (while accelerating)/alternator question

    I have used the same 15445 Belt with a 12si on my ‘75 350 for many years. The only time I get a short belt squeal is if the battery is low (left lights on, etc.) and I rev the engine up quickly. I assume the alternator starts to charge more to recover the battery and the belt slips a little.
  9. 75gmck25

    2.5” exhaust kit for 85 suburban?

    If you have a relatively stock vintage 454, slightly smaller exhaust will not make much difference. Just make sure you get good flowing mufflers and an H or X pipe so you make the best out of 2 1/4” exhaust. There are flow limits in the older heads, limits to stock iron intakes, low...
  10. 75gmck25

    2.5” exhaust kit for 85 suburban?

    There are many 2 1/4” kits, so they are reasonably priced and easy to find. There is only one off the shelf 2 1/2” kit for 2WD vehicles that I’ve seen, and I think the brand was Pypes. It was at least double the price of the 2 1/4” kits, but it was also higher quality tubing. How deep are...
  11. 75gmck25

    Fitech efi on 350 question

    The FiTech “wet manifold” design is similar to many other aftermarket EFI systems. Individual port injection is better overall, but there is nothing wrong with throttle body injection. The newer systems are usually self-tuning up to a point, and then allow individual adjustments to improve...
  12. 75gmck25

    Taller tires for my 1976 K20

    Was there ever an OEM “lighter” version of the 8 lug steel wheels? All major manufacturers used the same 8 lug pattern for a while, and I assumed it was only on 3/4 ton and higher GVW. Aftermarket did offer some 8 lug alloys, but I don’t know much about them.
  13. 75gmck25

    Fusible Link?

    I used a TS-6 sending unit on my ‘75 and it is a pretty close match to proper temperature reading. The correct ‘75 vintage GM sending unit is only available as NOS, so it’s usually expensive. My gauge has no numbers, but fully warmed up to about 185 degrees it shows between 3/8 and 1/2 with the...
  14. 75gmck25

    new to me 75 turn signal issue hlp

    When I replaced the turn signal switch on my ‘75 the switch they gave me did not plug into my wiring correctly. The spacing of the flat plug’s terminals was a little off. I ended up using crimp connectors to put the old plug on the new switch and it worked fine.
  15. 75gmck25

    Fuel Tank Replacement

    For an ‘86 you probably need a 3 port sending unit (feed from pump, return to pump, and vent). Get the right one now so you can set the truck up correctly with a fuel return line (prevents vapor lock and other hot weather issues), and venting.
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