I have seen various places for sale complete dash assemblies with mechanical gauges. My 74 has idiot lights and the large gas gauge on the left and speedo on the right. My question is since it is a printed circuit board configuration, how much of a PITA would it be to convert to mechanical vs idiot lights? Sending unit issues etc...

Thanks,

Earl

If you mean that you have two circular pods instead of the rectangular configuration on your 74 it sounds like you may actually have the SS configuration although idiot lights sound strange for that. I've had mine out I don't know how many times. The printed circuit isn't good for much more than the gauge lighting and of course the clock and idiot lights. I've seen conversions using fabricated aluminum panels with autometer gauges. What's nice is that the whole thing including the back support piece comes out with 4 bolts and one spring clip for the speedo once you get the facepanel off. The problem is it's not too easy to reuse it for support with anything other than stock instruments unless you can get really small shallow ones.

Anyway removing the whole assembly leaves a nice big hole with the speedo cable just hanging there. The new gauges would have their own sending units and lighting so you wouldn't have to worry about the printed circuit.

I left my stock unit in and just did a gauge cluster under the radio and a knee slapper tack just to the left of it.

Here's what I ended up doing..

http://members.cox.net/jwalk6/pix/elco-int-radio.JPG

If you mean that you have two circular pods instead of the rectangular configuration on your 74 it sounds like you may actually have the SS configuration although idiot lights sound strange for that. I've had mine out I don't know how many times. The printed circuit isn't good for much more than the gauge lighting and of course the clock and idiot lights. I've seen conversions using fabricated aluminum panels with autometer gauges. What's nice is that the whole thing including the back support piece comes out with 4 bolts and one spring clip for the speedo once you get the facepanel off. The problem is it's not too easy to reuse it for support with anything other than stock instruments unless you can get really small shallow ones.

Anyway removing the whole assembly leaves a nice big hole with the speedo cable just hanging there. The new gauges would have their own sending units and lighting so you wouldn't have to worry about the printed circuit.

I left my stock unit in and just did a gauge cluster under the radio and a knee slapper tack just to the left of it.

Here's what I ended up doing..

http://members.cox.net/jwalk6/pix/elco-ins-hagerty%20(9).JPG

So it sounds like if I got a dash with mechnical gages, temp, oil pressure, volts, I would have to deal with sending units for those gages. The sending units in my car that tell the idiot lights to illuminate won't work?

Yeah, The volts gauge can just be hooked into a tap somewhere on the fuse block that only operates with the key in the ON position. I use mechanical gauges and they don't use senders so much as adapters. A temperature sensing bulb for the water temp and a pressure line fitting for the oil pressure gauge. Electical gauges will have actual senders that screw into the same spots as the idiot light senders.

The idiot light senders are pretty useless for a real gauge as they are preset to only make contact at a preset level. I think it's 10PSI for oil and 240 for the Temperature gauge.

You can actually get a T adapter and run both the lights and the gauges if you want both but this does work out better with the electrical gauges.
For example, the bulb for the mechanical water temp gauge has to be long enough to stick into the coolant flow in the head. That could make the T adapter problematic and probably not let the mechanical gauge work too well. I've actually had a few autometer instruction sheets that covered installing electrical gauges with a T fitting.

:D

I am planning on doing the conversion from the big sweep speedo and idiot lights to a full factory gauge instrument cluster. I have already bought the gauge instrument cluster and gauge sender units but have not yet embarked on the change yet.

Here is some information I got from an old thread here on ECC which I have not fully interpreted yet:

74 El Camino Instrument wiring

Mostly a straight forward install except the pin connectors on the dash the ones that connect to the printed circuit board will all have to be re-clocked only the high beam indicator is in the same position but the improved look is well worth it.

1....lt green 10....blue
2....blue white stripe 11....grey
3....tan 12....lt blue
4....pink 13.....tan
5....tach lead 14....green
6....not used 15....not used
7....black 16.....pink
8....brown 17.....yellow
9....not used 18.....yellow black stripe