Off topic 660 holley help needed

Off topic 660 holley help needed

Joined: November 26th, 2003, 2:49 am

September 6th, 2011, 3:16 am #1


I just put a set of these on my cleveland but cant get the idle mixture to work at all,Things I have done to the carbs are 600 holley metering plates in the front to run power valves currently running 2.5 in them,also put a kit in the rear so I can use jets in the rear,right now I am running 76 front and a 73 jet on the rear.

Should I be jetting way down now that I am running a powervalve cause man she is running rich and will not idle very well at all below 1100 rpm,are the 600 metering plates a good swap or are they wrong for the 660.

Sorry Blizz but they are still on a cleveland so I hope that counts..

Tony
Quote
Like
Share

Joined: December 16th, 2003, 1:59 am

September 6th, 2011, 3:33 am #2

with a power valve in the primaries you need to drop about 8 sizes on the primary jet from stock

if the idle mix screws are non-op, you're not running off the idle circuits, check how much of the transfer slots are showing

but first, as you ask, are the primary metering blocks you're using compatible with the 660 main body and base plate? Holley uses at least 3 different flow path systems in various models for the idle circuit, some idle mix screws even work backwards going leaner as you open them out

call Holley in the AM and ask tech if your metering blocks are compatible(you'll need the numbers off the blocks)

and maybe see about having the PV provision added to the stock metering blocks

there'll be phantoms, there'll be fires on the road... and the white man dancing
Last edited by tinman351 on September 6th, 2011, 3:34 am, edited 1 time in total.
Quote
Like
Share

Joined: November 26th, 2003, 2:49 am

September 6th, 2011, 4:18 am #3


Thanks Tin

Good advice on getting holley tech on the ph,so I need to get a 68 jet in the front and most I have read on the 660 indicates it likes a 3 spread so probably a 65 in the rear. 
Quote
Like
Share

Joined: December 16th, 2003, 1:59 am

September 6th, 2011, 6:35 am #4

a while back Holley tech told me that 660's come jetted square @ 76 all around, so with PV's in the front you'd start at 68/76

here's where it might get tricky though,

did you check to see that the vacuum reference for the PV's through the base plate into the main body cavity exists?

and with a 1:1 pri/sec throttle ratio, the fat secondaries w/o any PV's are still gonna richen up the midrange- is that why you're jetting the sec's lean?

it might work if you enlarge the PVCR's to flow more full power enrichment fuel?

(power valve channel restriction's) they're the 2 small holes that meter fuel into the main well from the PV's. the power valves don't actually meter fuel, they're just an open/shut vacuum operated valve

there'll be phantoms, there'll be fires on the road... and the white man dancing
Quote
Like
Share

Joined: January 10th, 2002, 5:53 pm

September 6th, 2011, 2:43 pm #5

I just put a set of these on my cleveland but cant get the idle mixture to work at all,Things I have done to the carbs are 600 holley metering plates in the front to run power valves currently running 2.5 in them,also put a kit in the rear so I can use jets in the rear,right now I am running 76 front and a 73 jet on the rear.

Should I be jetting way down now that I am running a powervalve cause man she is running rich and will not idle very well at all below 1100 rpm,are the 600 metering plates a good swap or are they wrong for the 660.

Sorry Blizz but they are still on a cleveland so I hope that counts..

Tony
Quit screwing with the jets, they have almost nothing to do with the idle mix. Concentrate on the idle feed restrictions and idle air bleeds. They (660s) are supposed to be set for tunnel ram use, but when you switched to 600 front blocks your killed that - now you have two 600 model idles feeds so you have double the idle fuel flow - same as putting two non-tunnel ram carbs on a t-ram. Put the right blocks back in the carbs and start over.

1967 Falcon 4 door 351C-4V
1970 Mustang 351C-2V
http://raceabilene.com/kelly/hotrod
Owner built, owner abused.
Quote
Like
Share

Joined: December 16th, 2003, 1:59 am

September 6th, 2011, 6:56 pm #6

should be able to be duplicated

from my notes and talking to Holley & QFT tech i believe the 660 idle restriction orifice is .031" and the primary idle air bleeds are still in the 660 main body

IIRC the QFT secondary plates come with .039" idle orifices that may need tuning, i have here something about a 4-40 thread?

the big question is whether those particultar 600 primary blocks are compatible at all or can they be modified to work

Last edited by tinman351 on September 6th, 2011, 7:06 pm, edited 1 time in total.
Quote
Like
Share

Joined: November 26th, 2003, 2:49 am

September 6th, 2011, 9:56 pm #7


I got ahold of the holley tech today and they could not tell me if the metering plates are compatable or even give me a part # that would be but if I wanted to wait 4 weeks they could make me some new ones,they really were no help at all but reading a bit online I have read where others have done it but no mention of part #'s so I think what I will try is to put the stock metering plates back on, bummer is I have to dig up a spare one as only one of these 660's had the correct metering block.

Does any one have one laying around for a 4224....
Quote
Like
Share