Some updates for those interested enough to follow along. Over the last week or so I've been playing with JB Weld on the head. After finding out an oil drain back passage intercepted the head bolt boss my external oil mod was made in I needed to do something about it. After thinking of a variety of ideas to work around the problem, I took the sledge hammer approach and back filled the whole passage with JB Weld then drilled out the head bolt hole. It'll do for this project, the good head will have the external line tapped elsewhere. From the top. From the bottom. Then I started looking at the injector placement using the northstar injector caps. This is how I think the injector placement can go. Using MSpaint, the Green line is the fuel In and the Yellow line is the fuel Return. I'll likely use a steel U shaped tube under thermostat housing to make the bend tighter. So here is a completed injector assembly I'll be using. An injector bung, injector, northstar injector cap and electrical plug. For this experiment I trimmed the bung down to the end of the injector. I also installed freeze plugs into the engine and head. The parts store got me the steel ones instead of brass (they didn't ask and I didn't think to specify...), and I was tempted to send them back, but this engine should only be in the car around a year, so I decided they'll be good enough. The good engine will get brass ones. ---------- Post added at 09:58 AM ---------- Previous post was at 09:55 AM ---------- I thought about posting this part in the "High Tech for Old Iron" section since the DIY approach will work easily on cast iron Buick intakes as well. Actually my original plan was to 'practice' on an iron 455 intake, but it seems I don't have one on the shelf..... So I went all in on a not quite rare, but not quite easy to find 4bbl intake manifold on the OHC six. Same methods would apply to drilling a Buick intake. I have an aluminum Edelbrock one on the shelf I will eventually drill for EFI and install on the Centurion. Oh boy, I'm committed now!! I'll let the pictures show what I've done. First bank has the thermostat housing adding complication. I think I can slip the fuel line from injector two under the thermostat housing. Next up the Q-jet/carb/throttle body is the next complication. The electrical plug on #4 injector has to be turned around because it won't clear the cam housing. And the easiest pair at the rear. Actually I'll be using the fuel pressure regulator cap on this end. This one will lay out a bit different when finalized because the fuel pressure regulator. The intake now. I still have to clean it up and then epoxy the bungs in place. #4 currently sits loose in it's hole so on mock up it's not as angled as it will end up being. No fancy equipment here. First I drilled a pilot hole vertically, then using the same bit leaned on it a bit to give it an angle. Then I took a standard step drill bit that to open it up to 3/4". Actually I used two different bits because I have one that goes up to 3/4" that I've cut in half so it's shorter and won't hit the bottom of the port. This picture shows where I stopped with the regular bit before I cleaned it up with the cut bit, which of course when finished looks like the hole on the left.