Recent content by 75gmck25
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Alternator amps
Good point - the current 10si (or its wiring) is bad, and the simplest fix might be just to use a direct replacement. Alternator testers at the parts store seem to be unreliable. I think they just check for continuity and maybe some resistance values to see if they are within spec. They don't...- 75gmck25
- Post #27
- Forum: Tech Discussion
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Alternator amps
The CS130 and equivalent are excellent, but are a slightly different form-factor and wiring than the old 10si. Not a big job to adapt, but some folks don’t want to modify anything electric. My choice - The 94 Amp 12si is a drop-in replacement for the old 10si, and the 12si is sold with either...- 75gmck25
- Post #21
- Forum: Tech Discussion
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87' a/c brackets
Old R4 compressors are not great. Look for a kit to adapt a Sanden or Seltec and get the brackets they use. -
New memeber old mechanic 73 chevy 350
Welcome! Check the rear end to see if it’s a 14 bolt FF, which are used on the high GVW C20’s. Brake work on a FF is harder because you have to pull the axles to get the drums off or replace a wheel cylinder, so it gets ignored for many years. You might just have a really bad wheel cylinder...- 75gmck25
- Post #8
- Forum: Introduction
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Vortec Head Timing With Progression Ignition
Vacuum advance is not related to performance tuning, since as soon as you open the throttle the vacuum will drop and the vacuum advance goes away. You can mostly plug the lone and ignore it when first setting base and mechanical timing. Vacuum advance is there to improve the burn at steady...- 75gmck25
- Post #8
- Forum: Engine & Performance
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1980 C10 Cruise Control Switch 407437
Most common brand is probably Rostra, but Iditit and Dakota Digital also have them. Problem is that they are about $400 and up. GM cruise control was nearly identical across multiple model lines, so start looking at both GM car and trucks for the parts you need. Lots more cruise control...- 75gmck25
- Post #15
- Forum: Introduction
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75 Chevy SWB 4x4 adding a saddle fuel tank on driver's side
It’s a relatively easy mod once you get the parts. The fuel filler hose is not very flexible, so it has to match the filler setup (hole in bed side versus door). You need a 6 port or 3 port fuel solenoid, and matching wiring and dash switch. Original setup used sections of metal line running... -
Intermittent cruise control
I would start by checking the wires for chafing or breaks. The controller relies on a reliable signal from the speed sensor on speedometer cable (or in a '91 maybe it comes from the ECU), and it might be dropping out the speed signal. The other place to check is all the vacuum connections...- 75gmck25
- Post #2
- Forum: Tech Discussion
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Power loss with aggressive acceleration
What type of carburetor is on the 6 cylinder? When a 4 barrel has this type of symptom you would usually check to make sure the secondaries are working and properly kicking in, but I thought the 6 cylinder used a two barrel carburetor. The other items to check is the float level and the fuel...- 75gmck25
- Post #6
- Forum: Carb Fuel Systems
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1991 Suburban 3/4 ton: TBI to Holley Sniper conversion - stupid, or worth it?
To some degree, a Holley Sniper on the stock TBI heads and cam is like putting lipstick on a pig. Lots of shiny new parts, but probably not that much difference in power with stock cam and heads. To get more out of the sniper you will need more cam, but not one that goes beyond the compression...- 75gmck25
- Post #9
- Forum: TBI & EFI Conversions
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Bed liner paint.
I’ve seen a few factory trucks (don’t recall the brand) where they used a bed liner-looking paint to protect the rocker panels. Not sure what it was called, and I haven’t seen it used in quite a while.- 75gmck25
- Post #8
- Forum: Paint and Body
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Loose timing chain replacement
Also, if you get the idea to upgrade to a double roller chain, be ready for some more work. In most cases the extra width of the double chain hits the oil gallery bosses on the upper front of the block before the timing set is fully seated. It’s relatively easy to grind the bosses down for...- 75gmck25
- Post #6
- Forum: Engine & Performance
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What’s the best way to fix/clean up this wiring problem?
First figure out what all those wires are going to, so you understand what you have. Also, is this an auxiliary battery? Those large battery cables look pretty wimpy for a squarebody stock cable. The instructions for many aftermarket accessories state that you must make the power connections...- 75gmck25
- Post #5
- Forum: Electrical & Audio
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Instrument panel light question
My ‘75 did not have a light to tell you the parking brake was on, but it does have a wire going to the proportioning valve, which turns on the light in the dash if there is a brake line failure. This light works by grounding the wire to turn on the dash light. Newer trucks did have parking...- 75gmck25
- Post #17
- Forum: Tech Discussion
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Instrument panel light question
Taylor, I think the picture you posted is of a newer truck than the 74/75 era. For the older trucks I think it was just a single wire connected to that bolt, and in later years they added the bus/fitting for multiple grounds (like in your picture). I only found the missing instrument panel...- 75gmck25
- Post #14
- Forum: Tech Discussion
