Hi Adam,
Sounds like your goals are pretty similar to mine. I have to agree with Twilight in that the Q-Jet is one of the best carbs out there when properly tuned (and any carb must be properly tuned to work well). The small primaries give excellent gas mileage and the ginormous secondaries provide plenty of air for hard runs. The 68 I just bought has an Edelbrock and frankly I think it gets worse mileage. There really is no good reason not to use your Q-Jet; if nothing else do a basic rebuild on it and it will be fine unless the plate is warped (this is the benefit to a professional rebuild, they have the tools to check and fix plate warpage)
I actually bought a Summit Racing rebuilt Q-jet to hold me over til I can afford fuel injection next year. I bought the Aluminum Intake manifold that Gary Rockwell produces which has fuel injection bosses built into it and I am considering using the port injection design although I have yet to make up my mind.
I also have the Edelbrock heads and they do work with any stock intake. The Rockwell will work fine. I do note that the Edelbrock carb was installed on the stock iron manifold with a spacer and it just fits under the hood (I measured with some crushed aluminum foil and there was a little bit of clearance under the hood fuzz). If you choose to buy an Edelbrock it seems like it will fit fine on the stock manifold with a spacer, but in my opinion you are better off with Q-jet for now.
I think it pays to mention you have to be very careful with new wheels. You must respect the offset depth and other factors unique to our wheels; an excellent read can be found here:
http://www.breznick.com/toronado/wheels/index.htmAs for the disk brake conversion you may want to consider the Wilwood GM D52 Aluminum caliper which will replace the single piston stock caliper used from 69 to 78 in these cars. It is a two piston floating aluminum caliper that seems very nice; I will have installed my set soon and will be reporting back what my results are. There are several different models; you will want the 2" pistons and the 1.28" Rotor Thickness set in black or red:
http://www.summitracing.com/parts/WIL-140-11290-R/If you use a flat-tappet camshaft (you say Crane Fireball but that does not really tell us much and does not show as an actual Olds cam) then you need to be very careful when first starting the motor or you will flatten the cam lobe and dish the tappet. You need to use ~ 2800 ppm ZDDP (A Zinc-Phosphate Additive) in the oil and modern oils are only around 800-900 ppm so you either need an additive like Camshield or an oil that has the required level. Run the engine at between 2,000 and 3,000 rpm for 20-30 mins right after starting it for the first time, then drive for about 50 miles never keeping the rpms at the same level for very long. Change your oil and use oils with about 1,200 - 1,800 ppm ZDDP from then on. Rollers tappets do not need this break-in cycle.
Good luck with the headers...
