carb jetting

[mygasser]

hi it's me again from england, this time i'm after some advice on ballpark jetting for my 390 motor. build details are 30 over flat top pistons, thumper cam http://www.summitracing.com/int/parts/cca-cl33-600-5 with matched valve springs, ported stock heads, port matched streetmaster inlet, 1 3/4" fenderwell headers, 2" super sucker carb spacer, mallory dual point and coil and either 750 or 850 double pumper carb. the c6 gearbox has been rebuilt with street strip shift kit and 3000 stall 10" convertor. 9" axle with 4.11 gears and spool. 31" mt et drags. nearly forgot the car is an english ford anglia wagon 1964, built as an altered wheelbase gasser, here's a pic

my question/s are which carb (750 or 850?) and would anyone be able to suggest ballpark jet numbers before i take it to a rolling road (dyno). i ought to say i'll be changing the dizzy for an electronic one (this http://www.summitracing.com/int/parts/pnx-d7133800/overview/make/ford) with matching coil before the rolling road day if you think that makes a difference to my carb choice/jetting.
thanks again in advance for your help, neil.

[jayb]

Your car is really, really cool!  Great picture.

I think I'd be looking at a 750 double pumper carb, and leave the stock jets in it until you get to the dyno.  I think they'll be real close to what you need.  Will your dyno (rolling road) operator have jets on hand for Holley carburetors?  Usually jetting is one of those things you tune during the dyno session.

[mygasser]

thanks jay,
i'm real happy with how it's turned out. it launches very straight and although it's only about 8-900 kgs all up it doesn't feel too light at the top end.
i had a feeling the 750 would be the way to go with this (fairly mild) 390. i'll be putting a 445 together with my spare block so i'll keep the 850 for that. i wanted to make sure it ran straight before i put lots of power in it and i'm now happy to go faster next season. i'll use a rolling road familiar with holley's (not so common in the uk) and make sure either they keep jets or a buddy has an assorted box i can take and replace what i use.
thanks again, neil.