'77 911S valve covers

[77Targa0912]

Not sure on the history of the motor in the car, but it seems to be a stock 2.7 cis motor with a serial number in the correct range for the 76-77 model year. No COA Yet.

One thing I've noticed is it has black upper valve covers with red lettering. Is this oem or a sign the motor has been out and gone through at some point? I need to familiarize myself with what was oem and what is an upgrade.

So far I know the thermal reactors were changed for the 3-1 tubes and it has turbo ribbed lower covers.

I haven't dug any deeper to see if it has had the studs changed.

Motor has 125-140 compression on all six cylinders. Waiting on 6 injectors to come Friday. The car runs at idle but has smoke coming from the right bank heat exchanger and it backfires often at idle. Has the pop off valve in airbox.

Currently have replaced the fuel tank, fuel pump, tank filter, fuel filter, rebuilt fuel distributor, spark plugs, and waiting on 6 injectors. Points are like new and gapped correctly. Timing set at 5 degrees at idle.

I hope the injectors solve the problem and I can get the car on the street for the first time in 12 years.