So I just bought my 355 (finally!) yesterday, going to be dropping it in soon. It's from a 1974 Nova that my instructor is restoring for a customer. He rebuilt and restored this motor to show-car quality and sold it to me for $750 as a running engine. It has a good cam and ported heads and forged internals and a 650 cfm carb, it was supposedly pushing about 360-400 HP in the Nova with the ported stock heads.

So now.....I need to start the nightmare of getting all my gauges to hook up! Anyone have any experience with what I am getting into? Also, I have read I need to remove my electric pump and add either a fuel regulator or feed new lines to my tank for the mechanical fuel pump. Is this true?

 

All your gauge wires, and their senders, will go right into that motor, in all the same places. The only thing different is that you'll be changing from a cc-distributor to a vac-advanced distributor - there's a sticky eithyer in carb forum or engine swap forum about the wires for the distributor and which color attaches where for the tach.

Oil Pressure - in YOUR car it should be on the china wall, behind intake, driver side of distributor - only one wire.

There might be another oil pressure sensor/switch just above the oil filter - this one should have 2 wires - this is a sensor that senses oil pressure, and turns on the fuel pump if/when the computer doesn't. You can cut these wires, connect with a relay that also gets a ground and a hot-it-run, and thus your fuel pump will run with the key on (if you use the in-tank pump).

Water Temp - in YOUR car, should be driver side head, between #1 and #3 spark plug

Speedo will function as normal - connected to tranny, nothing to even touch there.

There's a gazillion threads on the fuel pump. You can retain the electric pump, and use a RETURN style regulator like the Mallory 4309. Or you can remove the electric pump, install a carb pickup line, and use a mechanical fuel pump on the motor. Or you can remove the electric pump, install a carb pickup in the tank, and use an electrical carb pump outside the tank. Obviously keeping the in-tank pump is easiest method, but sooner or later you'll need to replace it anyway.

You need to retain all the wires on the driver side - that's all the gauges, lights, fuse power, igtnition, etc. Most pass side wiring will not be used at all, and can be tucked away or removed.

I highly recommend not using the stock electric fan switch/relay, but rather get a seperate fan controller to run your fans - they probe the radiator, are adjustable, and don't use any factory wiring - easy to install.

 

Awesome writeup, love all that information!! How come you recommend using an aftermarket fan controller? Will the stock one have issues not turning on when it should?

When I had the 305 running in it, occasionally the coolant temp would get a bit high but come down later, didn't seem like a thermostat issue. Do the fans get a bit picky?

 

Your car stock has dual fans right? The ECM controls the primary (which you will no longer have), and the fan switch in the pass head controls the secondary (which I never liked cause I never had any luck getting one to work past 2 months) - that's why I recommend the seperate controller.

 

Wait, why won't I have the primary fan anymore?

 

You will but there is nothing to operate it now
If you have a CARB on the engine then you won't be using the stock COMPUTER anymore
which used to control the fan

As noted above ,you need a new way of turning the fan on

 

Oh I thought the ECM would still be hooked up just not operating much.

 

Hey um quick question about all the stuff you posted up top regarding the wires.....the motor has nothing on it as far as I know...it is a 1974 motor, I didn't think they have sensors for all that stuff...it's pretty much a motor and carb there was no real wiring in the car it came from. Am I not going ot have any gauges now in the Firebird if I go with this motor???

 

You transfer your senders from your old motor to the new, or else just replace them with new - only 2 of them, oil pressure and coolant temp.

 

Ok sweet. That is what's bugging me about this swap: getting the gauges correct and making sure I can have a speedometer ( haven't gotten it working since I bought the car). This vehicle is a wiring nightmare due in part to the previous owner and partly due to me having a bit of a hard time understanding what goes where. For example, when I was testing my injectors a while ago, I unplugged every relay and coudlnt find the fuel relay! Guess it runs on pixy dust or something.