what is your setup?

single 40DCOE or twin 40DCOE?
A12 or ??
Modified?

Air correctors - too lean (large hole) causes a miss at near max RPM, too rich (small hole) it will be soft and not give full power
Main jets - affect max RPM similar to air correctors
Emulsion tubes - affect the acceleration phase from progression onto full throttle and the main circuit coming into operation
Idle jets - affect alot! idle, off idle and progression onto the main circuit are all determined by this!
Aux venturi - also important for response
Choke - as mentioned sets the effective rev range of the engine
Accel jet - purely there to fill the hole created with sudden opening of the throttle causing a lean spot, you should be able to drive without these if the throttle is opened gently enough, don't use them to hide a weak progression!

At cruise you are primarily using the idle and progression circuits. The main jets and air correctors only really come into play once the throttles are 70-80% open.

Idle and progression are what give you driveability so you need to sort out your low rev issues.

What idle jets and holders do you have installed?
How many progression holes are there?

By all means work on the full throttle jetting but do it after you have fixed part throttle response!

You have three areas that the jetting covers: idle, progression and full throttle.

The chokes determine where in the rev range that full power happens, the smaller the choke the lower in the revs, too large and you lose response down low.

I would be disconnecting the accel pumps to check the idle and progression as it sounds like the top end is OK. With the pumps disconnected you can make sure that the accell isn't covering for a weak idle/progression mixture.
Once warmed up, very slowly try to accelerate through the rev range, without the accel pumps you will quickly find any weak spots in your idle and progression circuits. I repeat VERY SLOWLY or you will flat spot straight away due to the lack of accell pumps. As you move up through the rev range you will need to richen up the flat spots and lean the fluffy areas.

Once you can very slowly rev it cleanly through the entire rev range, reconnect the accel pumps and it should be pretty close..

Use this to compare against a known set of wheels you already have:

http://marksink.com/tire_wheel_offset/offset.html

It will tell you how much further out the rim will sit compared to what you already have.

I always thought larger on the exhaust.

The boost helps make up for smaller intakes by simply forcing the air in but the larger exhaust helps spool up a turbo quicker?

Also as DD says, boost will bring extra heat with it, especially if turbo'd so you need to take that into account with you seat thicknesses etc.

Sold awhile ago sorry..

Wot he said..

Check the timing is correct.

Then also as Benny said, check the idle to progression by disconnecting the accel pump and very slowly opening the throttle, it should just slowly increase in revs with no stumbling.

Got a link to a data sheet or manufacturers website?

I have successfully straightened diff housings before in a couple of ways..

1. pull it out and get it straightened in a press, best way to get it exactly how you want it, did this with my old rally car after it gained a few degrees of neg camber after launching off some major yumps..

2. use an oxy torch to heat the tube cherry on the side you need to shorten, then quench with a rag soaked in water, by doing this carefully you can "pull" the tubes any way you want, just need to keep measuring it to make sure you don't over do it. Can be done in the car as long as you are careful with the oxy, KEEP A FIRE EXTINGUISHER HANDY! Did this quite successfully with an Escort Atlas housing that had quite a tweak in a prang, got it back well within spec in half an hour.

Successful delivery and currently sitting here sipping on my fee