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 Calibr.start point 850 Demon on 572/620 Crate 
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Joined: Fri May 20, 2016 5:18 am
Posts: 117
I am "overhauling" a850Demon DP going on a -65 Impala 2d HT with a Chevy 572/620 Hp Crate engine TH 400 3.20 something gearing and 2200 ca converter.
The owner and his son think the carb has been working excellent fore a couple of years now, no leaks no flooding and it starts up perfectly well
( the electric choke was strapped open) the only issue the had with it ,is its stumble a second after take of on our local 1/8 strip in Malmoe
(Which happens to be the fastest 1/8 dr-strip in Europe )
They took the carb of and brought it over to me, to just do a "going thru, clean up and new gaskets.
OK i asked them to take a spark plug of and look to it and "yea very sooty"
The stumble of the line i figure can be no jet extensions in Sec and possibly .045 nozzles Pri and Sec,i figure that heavy car pettey stock convester and gearing needs a longer pump shot.
Any way This Impala is mostly a driver cruising car, with some strip action now and den so my biggest concern is to get it to perform as a good daily drivers car
withclean spark plugs.

Question is, has anyone a good starting recipe for this combo. I have it all drilled and threaded fore som action.

Demon 850 dp with down legs boosters and el choke.
This is the calibration it came with.

MJ pri 85 sec 93
MAB pri .030 sec .030
IFR pri .036 sec .036
IAB pri .071 sec .071
PV pri .65 sec .plug
PVCR .060
Pri E-bl E1 .034 E#2 .034 E#3 .034
SecE-bl E#1 .034 e#2 .034 E#3 .034
Pri nozzle .045 Sec nozzle .045
Trslr none .120
Trsl length .240
Trsl width .021
Booster legs .185
Ang ch .140

This carb has to be ready at Saturday for the "Burger King spring enrollment"

Figure fore a starting point i will set it up more like old 850 holley dp
plugg E#3 E#1.026 E#2 .026
Pri MJ 78 Sec MJ 82
IFR pri .032 IFR sec .032
pri nozzle .028 sec nozzle .031
Trsl .075
All suggestions are very welcome

Thu Apr 27, 2017 3:08 am

Joined: Fri May 20, 2016 5:18 am
Posts: 117
Oh i see i forgott listing pump cams, its pink pri and sec

Thu Apr 27, 2017 3:12 am

Joined: Fri May 20, 2016 5:18 am
Posts: 117
With 30 cc pri and sec pump

Thu Apr 27, 2017 3:40 am
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Joined: Fri Feb 08, 2013 5:50 pm
Posts: 2363
32 IFR will be small, try 35 in the lower location, 70 idle air bleed to start. 80/88 for jets with a primary only PV, .026 main air bleed.

Thu Apr 27, 2017 8:42 am

Joined: Mon Jul 04, 2016 11:37 pm
Posts: 51
Just curious but what type of fuel are you running in Europe on this carburetor.

Thu Apr 27, 2017 9:31 am

Joined: Fri May 20, 2016 5:18 am
Posts: 117
Pump gas premium 98 oct converted to Ron+M/2 is about same as US 93 Oct i think.
Besides winter summer fuel with different alcohol delusions there also is a EU demand of every EU country that at least 5% of the fuel must be renewable
so the easy way is to have 5% ethanol in al pump gas. And what a heck why not just be best in class and use a 10 % ethanol mix in all pump gas (5% to 10% rape seed oil in diesel )
Politians obviously don't drive Hot Rods :w00t:

Thu Apr 27, 2017 4:00 pm
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