Just some quick questions here..... I'm not a third gen guy as I mentioned in other post about my dads GTA a month or so back. Anyways helping him solve some issues with his 305 and I think I've isolated them now,.... There was a bad ground to the ECU and 3 injectors were bad registering under 9 OHMS........

About to remove the upper to change injectors and double check vacuums under there. Is it striaght forward??? I can get the upper and lower in my 302 mustang off in like 20 min,.... Or is there anything I need to know??? Special tools, runner removal,.. Etc??? Thanks for the help.

Ryan

 

It's actually very simple. I've taken mine apart so many times I can probably do it in 5 minutes. I can't remember how many bolts there are but all you'll need is a torx bit, as long as they're the factory bolts. IIRC there's one bolt on the driver's side back by the distributor that can be a pain. Just unbolt the runners from the plenum and the lower manifold and everything will come apart. Make sure you get some new gaskets as the old ones will probably be bad. Also a lot easier if you remove the TB. Which I'm sure you already knew that.

 

Remove the throttle body, remove the linkage on the side of the plenum that holds the tv cable and accelerator cable. Then remove the runner torx bolts. The rear bottom ones can be a bit of a pain,but just use a swivel extention. Then as you are lifting off the plenum, you will have to unplug the IAC connector (underside of the plenum). I re-use my gaskets.

 

How many of you guys have changed those bolts out? If so did you re tap the threads for the plenum?

 

why would u need to re-tap?

 

I just did a rebuild and I believe I cross threaded the plenum bolts. The bolts going to the heads are fine and the threads are good too on the heads. I bought the car used and I don't think anyone really took any care when the plenum was dismantled previous times before me. This is something that needs to be addressed and I am just asking around to see what people think. With the aluminum manifold, it is more than easy to accidentally cross thread in the upper and lower plenums.

 

i wonder why they had the plenum off.