17057262

[Holden350]

Hi guys, I've joined from Australia, and this is my first post. I'm running a near new 350 chev in my 1972 Holden ute. 10.5 compression, mild cam, alloy heads, and balanced. It runs at 11 inches of vacuum at idle. Current Qjet is a 17057262 73 primary jets, 44L primary rods, K hanger and DX secondary rods. Motor runs well, just on the lean side, spark plugs are always dark ash grey colour.
Float height is 9/32, and the choke pull off is a VB45. The rest is stock. I have another 17057262 Qjet, and I want to trick it up. Any suggestions please. I've have Cliffs book and was thinking of using recipe 2 on page 113. Cheers

[Cliff Ruggles]

If it runs well then it's not lean.  We tune for performance not for how plugs look.  I've found it difficult if not near impossible to read plugs on any of this new fuel.  Lean at part throttle it would be "flat" for power, require too much throttle opening, hesitation/stumble/bog coming off idle, and even "surging" at steady cruise.

What cam and heads are you using on your 350 build?

What distributor and how much initial timing, total timing and how much added by the VA?

Only making 11" vacuum tells me you need to modify the idle system as those carbs were pretty limited on idle fuel delivery.  73 jets with 44 L rods are PLENTY for jets/rods on the primary side. 

Those carbs came with DB secondary rods, I would use AX, CE, DA or CV rods instead.

I ship overseas daily if  you want to assemble it with the best parts in this industry and lifetime warranty in any fuel......

[Holden350]

Hi Cliff,

cam is 214/214-112
heads - I'm not sure about. They are alloy, with larger valves and ports, roller rockers
HEI distributor, recurved, 12 degrees TDC, 8 degrees VA.

The engine idiles fine, no bog or surging at any stage, and good on fuel.

A/F ratio cruising is 16-17

Do you think your recipe no.2 would be good for my other 17057262?

Thanks again

[Cliff Ruggles]

Difficult to recommend an exact "recipe" without knowing what heads and the compression ratio.

If it's only making 11" vacuum at idle speed and 214/214/112 cam the compression ratio isn't al that high or cam is retarded a bit.

If they are factory heads they will have casting numbers on them but you have to remove a valve cover to see them....