Lots of good information here that I will second.
On builds such as this I always ask the question..., what is the actual desire or end state of the build. If you are going to make a nice streetable restoration and keep the C3 (CCC) system, then you have to work within those parameters. If you want to go beyond that, you need to build with in those parameters.
Q Jet is a very good carb, robust and reliable if setup correctly. So is the Holley and also the Carter AFB (now sold under the Edelbrock name).
Yet each are different in how they go about metering the fuel and air.
From what I hear with your build and only my suggestion I would do the following...
Pre 1981HEI with vacuum and weights. Holley Q-Jet replacement with 50 cc pumpers on each end and 1 inch spacer plate. Low rise filter that will allow 3 inch filter and still clear hood. Care of the initial setup of the filter stud or you end up jamming it into the hood and now you have body and paint to fix. (Been there done that, Got the t-shirt).
10:1 static CR initial timing at 0 to 4 BTDC. Cam LSA about 106 to 110, total timing still going to be about 32 to 36 maybe a little more depending on lift and duration. You need to do the calculation for dynamic compression and keep around 7.5 DCR to use 87 pump gas without major worries.
Headers 1 3/4 instead of 1 5/8. Watch the header selection Engine Masters episode from Frieburger (sic) available on YouTube.
The only Olds 350 that used C3 system was the Tornado/Eldorado, but I think most were TBI, not sure. I had a friend that had a 84 Eldorado, Olds 350 with a Carb I think..., been too long ago. The next closest was the Suburban Fleet police issue Chevy 350 with CCC Q Jet.
I'm a firm believer in measures, so an air/fuel gauge is important. If you don't want to or maybe not good at welding there are actually clamp on kits. About 40 USD, and if me, I would do both headers as you can check and see both banks in sync and not one richer or leaner than the other.
On setup you drive it and get you vac reading at WOT, you should be about .75 or less. From there you know if you are under or over on the carb CFM. You have to do the calculations on this. But likewise, if it's driving ok and your happy with the performance don't have to change it.
On the 2004R there is a pressure port when in OD, and this is where you want to mount the switch. Sounds like much but it's actually and easy process. I'll try to find you some pics on this.
On the 2004R the TV cable has to be setup correctly. You want 100% TV by 90% WOT, there are geometry correction kits for this,but as others have said, don't just go by the kit. You might have to customize it a bit. Each one I have done this was the case. This is true for 700R4 as well.
If your cam is staying closer to stock then 2400 to 2800 stall. If your cam is more open than that getting close to 220 duration or more then 2800 to 3200. You also at that point need to decide if you want to upgrade the input shaft. The original 2004r came with what was known as the small diameter 27 spline input, but can be changed.
The 2004 will be ok for awhile if you are not jumping on it to much, but won't last long. 2004R upgrades is good quality performance lock up converter. Up grade to 13 vane pump and pump boost valves, stator support and billet input shaft. Change front piston to the machined unit and add extra clutch plate to the OD. Then use the upgraded forward drum with billet shaft tigged in place, hardened shell and hardened output shaft. Several of the bushing can be changed to bearings. Another weak point is the band and it can be upgraded to a wider band and the accompanying servo to the billet unit.
Then from there the rear end. 3.08 is decent highway gear, but 3.42, 3.55, 3.73 are better around town gears. Gears just end up being more in tune with how you drive it.
Sounds like a lot but you don't have to do all at once.
