440 6 pack jet, power valve and float needle and seat questions

[shutudown4]

I’m rebuilding my 1970 440 6 pack set up and need answers regarding best jet size, power valve and gloat needle and seat parts to use. It’s going on a 440 motor stroked out to 526 in.
Two different Holley technicians told me it IS a streetable setup even w the 350 cfm center carb.
It just needs larger primary jets bumped up to a larger size - approximately 65s
But didn’t have info re: power valve and float needle and seats
Anybody have any answers, ideas?
Thank you
Shutudown4

 

[Bewy]

Start with std jetting. A bigger engine doesn't necessarily mean bigger jets because the bigger engine creates more depression [ suction ] & pulls more fuel.
A good example is in the MP bulletins. A TQ on 340-360 had 0.169" sec jets. TQ on a 440 had 0.137" sec jets.

 

[CRUZE 418]

I am a lot larger than that with my sb stroker. Engine leans over with 65's. Depends on the gas your using also. As far as the power valve, depends on your vacuum. Yes, big cubes do draw harder.
Make sure that you get the correct carb base gaskets for a 6-pack . They do make different needles and seats, large window ones would probably be better.
Picture, note the thin black line on the left side of the gasket, that's a big vacuum leak on the center carb. Same gasket won't work on the end carbs either, interference with the throttle blades. Got them from Chicago carb, threw them all away cause they were stock from 3 years ago. Promax base on rear carb? Promax conversion to jets from metering plates?

 

[shutudown4]

Im running a 1970 440 6 pack setup
Motor is stroked to 526 in.
It’s running very rich at 1000 revs idle
I know the factory jets are 62s
I talked to a very unfriendly tech at holley
He said use 65s and then I heard a click
PV is 6.5
What’s a good initial setting on the secondary carbs idle circuits? (Turning them in to have a more lean situation?
Any info is much appreciated
Any websites that might help?
Shutudown4

 

[CRUZE 418]

Have you ever read how to tune a 6-pack?
End carbs, start with 1/8th turn out. I then put a finger over the outer air bleeds, does the engine idle go up or down. Did or have you had a backfire? Could have blown the power valve. What's your fuel pressure? There are so many little things. 65's , my opinion, should be lean. Your getting fuel from somewhere.

 

[Bewy]

Might be too much T-slot exposed at idle on the middle carb. Should be 020-040, & 060 or more is too much. The extra cubes, plus a hot cam, will both require more throttle opening. Until you get the T slot correct, it will never idle properly. I suggest you check & report back.

 

[Daves69]

Any websites that might help?

Some info here and links to a 7 page article at bottom that may interest you............

The 6 Bbl tips

Some rebuild videos on youtube also (Back 9).....