Removing plenum in 1980 308GTSI

My 82 GTSi has 4 short hoses under the plenum. The two straight hoses are 40mm. I use gates green strip 3ft and cut what I need for all the main lines. The two 45deg hoses one on the front bank one on the rear bank I use gates 21461. Be extremely careful with the 8 spacers inside the 4 gaskets for the plenum they will fall into the intake if you're not looking for them.

 

Get a new gasket for the plenum. The spacers will fit tight in a new gasket.

 

Buy a SnapOn open end wrench that is an open end wrench at both ends, and the same size at both ends,
with the ends differing only in a slightly differing orientation. At the rear of the plenum there is very little space
to place your hand and move it. With this wrench you can turn the bolts at the rear of plenum a few degrees,
change the end of the wrench so that you can turn it a few more degrees, do it again and again, and get
the bolt off after 15 minutes or so. Then you can go after the next rear bolt. The size of the wrench is,
of course, the size for the bolts which I have forgotten.

Stuff the space behind the plenum with rags to capture the bolt which you may lose when it comes off.

 

I replaced all the coolant hoses on my 84 QV this spring, including the short hoses under the plenum. I did not need to remove the plenum to get them - the key is if the hose clamps are aligned so that they can be accessed from the side, with a screwdriver or socket between the plenum runners. Extra access can be gained by removing the large breather hose running under the plenum from the oil vapour separator (left side of engine beside forward cylinder head) to the connection on the underside of the air filter box.

Depending on the hose, you may need to remove the thermostat assembly as well - I can't imagine changing either of the two short hoses connecting to the thermostat assembly under the plenum without having that assembly loose.