Click on image for the lowdown. 
====
| | | Forums66 Topics128,042 Posts1,055,515 Members48,424 | | Most Online14,466
Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down
with Ads!  Again, thanks!
| | | | Joined: Oct 2018 Posts: 30 Olddog | | Olddog Joined: Oct 2018 Posts: 30 | I own a 1948 GMC 1/2 ton, put a 305 w/alternator, 12 volt
System. Question: do I need reducers on all my gauges?LMC truck said Not on amp gauge, how about Oil gauge, temp gauge, fuel gauge, aren't they all mechanical?
Bought a EZ wire 21 circuit harness, I assume this harness will be fine. Just wondering about these reducers. Any help most appreciated.
Yankabilly. | | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | Isn't fuel guage electric? Temp gauges come both ways, is there a Cu tube going to a sensor in the head or electric wire on sender?
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: Mar 2010 Posts: 10,272 Renaissance Man | | Renaissance Man Joined: Mar 2010 Posts: 10,272 | I don't use a reducer on the original fuel gauge. I have found that the biggest issue with bad readings with 12 volts is due to improper bends in the sending unit float arm, not the applied voltage.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
| | | | | Joined: May 2005 Posts: 8,983 Sir Searchalot | | Sir Searchalot Joined: May 2005 Posts: 8,983 | Your gas gauge is electrical. If you are all mechanical except the gas gauge, you can do like Carl or buy this.You will have to tell us, if you have mechanical. As said, if the under hood sender has a tube instead of a wire, it's mechanical. The 305 V8 would have electrical senders. So if you have original gauges, someone had to adapt 1948 to 1973, and up, compatibility.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
| | | | | Joined: Oct 2018 Posts: 30 Olddog | | Olddog Joined: Oct 2018 Posts: 30 | I would like to say thank you to each of you for your help, it is much appreciated!
Yankabilly. | | |
|
|
