All ignition components are original mercruiser as when the engine originally had a Quadrajet carb. Zéro fitech stuff only the throttle body was fitech

Doesn't your fuel presser seem low ? I thought carbs needed 7,8 lbs........I also was thinking vacuum leak as SB stated

Edelbrock was very specific that this carb cannot handle more than 6 5 psi so I started at 4 and upped it to 5.3. This did not have any effect and the pressure stays steady even on revs so I think the bowls are maintaining fuel levels. As far as vacuum, I can't see where there could be a leak I even smeared a thin coat of permatex rtv on each side of each gasket to be sure of that possibility upon installation. Edelbrock has said the problem lies with the mixture screws and the idle screw. Only I'm not sure how to go about adjusting them to at least get a start on idle and not on throttle.

Did the carb slide on adapter fine ? Many of these adapters had the stud holes slightly off (too close together) causing too tight for carb too slide on easily. Peep’s had to make carb mounting holes bigger.

Any vacuum ports not plugged ?

5ish fine on edelbrocks.

Spray something around the base while running and see if the revs go up, but be careful of the exhaust

heres a video you can watch.I'd try pulling idle mix screws and blowing air into the carb.

I have an Edelbrock on my 32 Ford coupe w/mild 327 small block. That thing never has idled the same from one start to the next. It is coming off this winter and I am going to put the old Holley (re-built) back on or a Quadrajet.

Good idea. :thumbs

Only thing making any sense at moment. This would drive me nuts. Not sure what production date carb is but since and during Covid era I found many parts to be fked up.

is it possible there’s buggered up cast flashing in and surrounding the adj ports? Fuel pressure definitely not an issue at least idle for certain so if nothing else changed during this swap wtf 😳

Edelbrocks are easy, but you gotta do step by step.

First, we will ASSUME your ignition timing is IN THE BALLPARK for now.

Edelbrock is good w 5 to 8 psi.

If the carb is brand new out of the box, then it will probably be a touch on the rich side, which is safe.

You need a vacuum gauge, and a timing light.
Hook the vacuum gauge to the fulltime vacuum port (not the "ported vacuum"). Count the number of turns required to close the idle mixture screws, and then put them back where they were.

So, for initial settings, do whatever you have to do to get the engine up above 140 degrees or so. THEN adjust the choke fully open for now. Then set idle stop screw to 800 rpm.
Take note of the vacuum reading.
Then turn the idle mixture screws IN 1/4 turn and see of the vacuum drops or rises. If no big change, turn another 1/4 turn. If vacuum is weaker, then go back to the original settings and 1/4 turn OUT and watch vacuum. Keep turning (both in 1/4 increments) until you see MAX vacuum.
If, at any time during this, the idle increases past 1,000 rpm, readjust the idle stop screw back down to 800 rpm. Keep repeating the process until you've found the setting that gives max vacuum at 800 rpm.

NOW look at where you ended up - if you landed at more than 2.5 turns out, then it is likely that your jetting may be too lean on the "needle down" position (you can refer to the jet/needle chart that came with the carb).

Once you get your idle mix set, then move your timing around, also watching the vacuum gauge. Once you find the timing setting that gives you best vacuum at 800 rpm, (again, you may have to adjust the idle stop screw) use the timing light to see where it is. Write it down.
But if you are using the normal V8 Module on your T Bolt ignition you should not run more than 10 BTDC.

Let's say you end up at 10 BTDC and 2.5 turns out on your idle mix screws at max vacuum at 800rpm.

Now you should go drive around at mid-cruise and be sensitive about listening and feeling for rich/lean conditions.

If you're happy with that, then set your choke per normal procedures (it has to be done when fully cold).