Not sure what the list # is on a borrowed 850 dp,from Mr. P-Body,what are the majority of them jetted at? 80-88,76-84???? My GTX runs cleaner jetted at 78-86,but runs cooler at 80-90. Also,seems faster on the top end. Haven't had it to the track as of yet this season! Sooon! RandyB

If it is a 4 corner idle 850 it should have .081 on the primary and .080 on the secondary. I have 3 of them.

Merc,it's a 4-corner idle model! So,you're saying 81 jet primary and 80 secondary,I'm assuming both PV's are installed! I never run a secondary PV,just the primary,when street driving. At the track,I square-jet all four corners. RandyB

7 plug wires??? I'll even throw in 32* total timing,and shift at 5500 rpm!

Oooops my bad primary is .080 and secondary is .078. Im getting old and memory is fogging. Get me the list # and Ill double check my Holley ref guide.PS here is a pic of my X...10.84 at 122.1.49 sixty ft. 493, pump gas, eddy heads, 3.73 gear. 3960lbs w/driver

Robert, SWEEEET cars! Is the Challenger a T/A? I'll try to get the list # tomorrow. Hopefully, Raff(Mr. P-Body)didn't grind them off when he made some modifications to it! RandyB

So Raff,you trying to tell me that senility's startin' to set in? I realize you're gettin' up there in years! On the carb... I went from 80/90 w/front pv to 74/84 and it really runs clean,and stronger than I thought it would! Had it runnin' in the pole barn,and the fumes were minimal! I still need to get it over to Jake and get it all dialed in correctly! RandyB

Is one better off running both pv's on a street/strip car?

How you been Randy? I run your basic Holley 850 DP also. I dont remember the stock jetting but I have 78's and 86's in it now on my 906 headed MP.557 cammed 440. I jetted the secondary from 84's to 86's and picked up about 1 mph so I left it like that. The car burns fairly clean and never fouls plugs at all putting around town. I put over 100 miles on the 63 this past weekend and it runs great. I would think your engine may take more jetting then mine as your eng is a bit stronger then my 440. I know you sure have it running good. Ron

Randy I was doing some looking around and seen this
it might help you(and this list number sounds familiar)

4781 850 (F)80,(R)80 6.5,6.5 4150
4781-1 850 (F)80,(R)80 6.5,6.5 4150
4781-2 850 (F)80,(R)80 6.5,6.5 4150
4781-3 850 (F)80,(R)78 6.5,6.5 4150
4781-4 850 (F)80,(R)78 6.5,6.5 4150
4781-5 850 (F)80,(R)78 6.5,6.5 4150

Adjust the secondary accordingly for no PV

Thanks,Ron! The X is running pretty strong! Mike,looks like the baseline jet is a 80. That was my guess. The Demon 850 was also a 80 primary. See ya at the Cutter later! Randy