Rally Dash conversion 73'

[Beer]

Info on whats required for the conversion, and issues encountered by those who completed such appreciated 

I believe the cluster and (engine) harness (as well as sending unit swap ie oil idiot light unit vs pressure unit) is all that is required?

CHeers
Beer

[Nacho-RT74]

I already made it.

concerned to parts on engine bay, yes you only need to change the oil sender.

concerned to wiring, they are TOTTALLY different... If you have the patiente you can cut the multiconector pin of the standart cluster to drive individual wires with 90 º female bullet kind to every gauge on the rallye one, and all the bulb sockets ( one wire ) individually with wiring ( orange line ) form a main splice, beside that, the double wire socket to the parking brake, and female spade terminal to the cluster voltage limiter. also the spliced wiring to feed the gauges from the limiter.

IMHO is a lot easier and maybe even cheap and safe, try to find a 72-73 underdash wiring... 71 is different just because the wiper switch plugs but use the same wires, so if you use a 71 underdash wiring you can just replace the plug. Also heater/AC swithes are different between 71/72 and 73/74, but is the same as above, just replacing the plastic plug to the right one... or the complete A/C-Heater control LOL.

No matter if you find an AC or non AC underdash wiring, since that harness is a separate one, only linked to the underdash wiring by a black wire with female spade terminal to the blower switch ( on heater system or AC system switch, is the same wire connected just on a different plug ).

Just in case I have diagrams.

Note: 74 harness IT IS completely different on both cases ( standart and rallye clsuter ) because the seatbelt interlock system but easy to modify to earliers.

[Nacho-RT74]

allmost forgett this:

you can use the same engine harness that you car already has, is just change the oil
sender...

and if you change the underdash harness, be sure that bulkhead conector matches with engine bay harnesses, since on some years wires could it be turned around, anyway is easy to match... piece of cake.

you can use ANY B body 71/73 underdash harness.

[NHCharger]

I changed to a Rallye cluster in my 72. Got a rallye cluster from a 73 and used my 71 FSM as a guide. . As you mentioned you need a different oil sending unit. The only problem i encountered was a few wires were not the same color as my manual showed.

[TruckDriver]

Ok, so, why do you have to change the oil sending unit? That part confuses me

[NHCharger]

Ok, so, why do you have to change the oil sending unit? That part confuses me

The unit for the idiot light is different than the unit for a gauge. When I swapped mine I did not change the sensor unit. When I started the engine the oil gauge would peg and then slowly fade to zero.

[TruckDriver]

I shouldn't have to change mine then cause my car already had the oil gauge. Right?

[Nacho-RT74]

right...

You don't have to do anything that requireas an extra job to change from one kind to another kind of rallye cluster...

if is with clock, just feed the clock directly from black side of ammeter stud if new cluster doesn't have it... normally the cluster has it attached, since is hard o loose that wire

if is tach... wire from negative terminal of coil  and wire from accesories source

[TruckDriver]

Well, thats easy enough then, thanks.