Re: 850 holley from sq jet,boost to frnt pv n/a
[Re: Clanton]
#2296871
04/30/17 11:33 PM
04/30/17 11:33 PM
|
Joined: May 2011
Posts: 4,489 northern,Ohio,USA
Clanton
OP
master
|
OP
master
Joined: May 2011
Posts: 4,489
northern,Ohio,USA
|
I still have the pv plug in the sec circuit and 88 jets but the pri has 76 and the 2.5pv,32 squirter,orange pump cam 1# hole and just checking things out in the garage it was lean n backfire in the intake/carb.I only have a 4.5 and a 6.5 pv to work with beside the 2.5 but my carb jets are from 76 to 90 and I think factory was 80 with pv's in the pri.The timing is at 32 to start 93 octane. ps the carb is an 4150 with choke horn no plate in it,factory air bleeds non adj.
|
|
|
Re: 850 holley from sq jet,boost to frnt pv n/a
[Re: Clanton]
#2296922
05/01/17 12:50 AM
05/01/17 12:50 AM
|
Joined: Jul 2004
Posts: 19,318 State of confusion
Thumperdart
I Live Here
|
I Live Here
Joined: Jul 2004
Posts: 19,318
State of confusion
|
Idle has no impact on the p/v unless it's loose or ruptured.......steady state cruise and a couple inches below that will get ya close then pvcr sizing and secondary jetting accordingly.............What list number or size is it...........
Last edited by Thumperdart; 05/01/17 01:24 AM.
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
|
|
|
Re: 850 holley from sq jet,boost to frnt pv n/a
[Re: Clanton]
#2297055
05/01/17 12:07 PM
05/01/17 12:07 PM
|
Joined: Jan 2003
Posts: 14,515 So. Burlington, Vt.
fast68plymouth
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 14,515
So. Burlington, Vt.
|
I'd start with a brand new 6.5pv, and 78/88 jets and adjust from there. This is assuming you're using a 4781/850 carb.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
|
|
|
Re: 850 holley from sq jet,boost to frnt pv n/a
[Re: fast68plymouth]
#2297105
05/01/17 01:30 PM
05/01/17 01:30 PM
|
Joined: May 2011
Posts: 4,489 northern,Ohio,USA
Clanton
OP
master
|
OP
master
Joined: May 2011
Posts: 4,489
northern,Ohio,USA
|
I'd start with a brand new 6.5pv, and 78/88 jets and adjust from there. This is assuming you're using a 4781/850 carb. Yes it is a 4781,The 6.5 has been sitting in a tray for 15yrs from when I got the carbs and seems to be ok when put vacuum on it in my mouth.I wont be driving in the rain today but will check the carb over again.Thank you for your help.
|
|
|
Re: 850 holley from sq jet,boost to frnt pv n/a
[Re: Clanton]
#2297116
05/01/17 01:42 PM
05/01/17 01:42 PM
|
Joined: Jan 2003
Posts: 14,515 So. Burlington, Vt.
fast68plymouth
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 14,515
So. Burlington, Vt.
|
If the rubber diaphragm gets stiff it changes the point at which it opens/closes.
They don't have to leak to not work properly.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
|
|
|
Re: 850 holley from sq jet,boost to frnt pv n/a
[Re: Clanton]
#2297130
05/01/17 01:53 PM
05/01/17 01:53 PM
|
Joined: Aug 2003
Posts: 43,352 Bend,OR USA
Cab_Burge
I Win
|
I Win
Joined: Aug 2003
Posts: 43,352
Bend,OR USA
|
Holley made many 4781 from the original with no power valve in the secondary to the 4781-9 I think with power valves in both metering blocks, I think my 4781-2 didn't have a power valve in the secondary ![shruggy shruggy](/ubbthreads/images/graemlins/custom/shruggy.gif) My 4781-6 came with one size smaller jet in the rear than the primary jets where What is your - list number ?
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
|
|
|
Re: 850 holley from sq jet,boost to frnt pv n/a
[Re: Clanton]
#2297150
05/01/17 02:30 PM
05/01/17 02:30 PM
|
Joined: Jul 2004
Posts: 19,318 State of confusion
Thumperdart
I Live Here
|
I Live Here
Joined: Jul 2004
Posts: 19,318
State of confusion
|
Get QF 4 window p/v...............
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
|
|
|
Re: 850 holley from sq jet,boost to frnt pv n/a
[Re: Clanton]
#2297219
05/01/17 03:59 PM
05/01/17 03:59 PM
|
Joined: Aug 2003
Posts: 43,352 Bend,OR USA
Cab_Burge
I Win
|
I Win
Joined: Aug 2003
Posts: 43,352
Bend,OR USA
|
Is this carb. on a intake now and not on top of the blower?
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
|
|
|
Re: 850 holley from sq jet,boost to frnt pv n/a
[Re: Clanton]
#2297941
05/02/17 10:02 PM
05/02/17 10:02 PM
|
Joined: Jan 2003
Posts: 6,591 Canton, Ohio
Sport440
master
|
master
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
|
I forget,is getting vacuum from the dist port ok on the metering plate or in carb base is better? That can be a debate in itself. Carb base vacuum may pull in all the vac timing at idle, witch you don't want. But with your big cam maybe it wont. The meter plate will pull vacuum in at a higher rpm. Try both see what you like best. The metering plate port is the one your really supposed to use. But, if you don't do much street driving/cruising, you really don't need it at all.
Last edited by Sport440; 05/02/17 10:17 PM.
|
|
|
Re: 850 holley from sq jet,boost to frnt pv n/a
[Re: Clanton]
#2297988
05/02/17 11:24 PM
05/02/17 11:24 PM
|
Joined: Jul 2004
Posts: 19,318 State of confusion
Thumperdart
I Live Here
|
I Live Here
Joined: Jul 2004
Posts: 19,318
State of confusion
|
If you're reading vac then the base and is your timing locked.......
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
|
|
|
Re: 850 holley from sq jet,boost to frnt pv n/a
[Re: Clanton]
#2298511
05/03/17 09:28 PM
05/03/17 09:28 PM
|
Joined: May 2011
Posts: 4,489 northern,Ohio,USA
Clanton
OP
master
|
OP
master
Joined: May 2011
Posts: 4,489
northern,Ohio,USA
|
yes the timing is locked at 32 for now and I will need to drill,tap for the vac so that will come later or maybe not with all the rain I am getting.I ended up sq jetting it again checking for leaks and test the backfire I had.87pri 88 sec no pv's it revs fine and power brakes well so I will test drive it like that when I get the chance[rain].jetting with a pv may take a 82 in the pri side.I would have tested that jetting but I was running out of time. ps:the point of driving it sqjetted is to check the trans shift,fluid,brakes and other things.
Last edited by Clanton; 05/03/17 10:03 PM.
|
|
|
|
|