Air/ fuel tuning
I'd go to a .032-.033 IFR and see what it does.
at gentle off-idle and steady crusing under 40 mph.
However I'm also seeing a lot more (as is Crackedback). It all depends on what you're after and what you're into. If you enjoy tuning that's different than if you just want it to run in a way that you like driving it.
So, after looking at your engine specs, here's how I look at what you've reported:
28 locked timing
idles good about 14:1
idles 1400neutral 1000drive
vaccum is around 10.5 at idle
as for driving around the street the gauge jumps a lot and at very light throttle and off idle , gauge reads 10.5 and 11 s quite a bit.
The idle AFR is really 10.5 to 11 that you saw in off-idle while driving. Opening the IABs a hair may lean that out a bit. Idle should be rich, especially with that cam. Whether its 11 something or 12 something or 13 - that you have to experiment with as your engine is different than the next guys. If its too lean, it will hesitate or miss when gently coming off idle.
cruise is 13 - 13.5
was cruising on the freeway today, and at 60mph about 3100rpm, cruise was always min 12s maybe even low 12s so after about 100kms , i decided to try a smaller jet .
put in a 76/86 combo now. cruise changed to 13:1
At least you know the main circuit is taking over from the idle circuit when cruising at 60 mph. If you want to work on this, keep taking them leaner until the engine tells you its too lean by surging. Do this some place you can slow down and even pull over. You'll have to change the jets or drive back at a slower speed. Do NOT test WOT.
If you find the jetting for high speed cruising is different than best power (on the dyno), then change the power valve restrictions. If the best power was with 78 and your most efficient cruising is 75, then the PVCRs get enlarged.
and wot is around 12.8
If that's where it did best on the dyno, then that's a good baseline when you go to the strip. Tune to the best mph, not the AFR.
then full throttle
i get 14.5 approx , but after 2 seconds of WOT it drops to a safer 12.5.
Same question as crackedback asked :) But also, how did it feel? Several posibilities here. Also depends how you pedelled it open. While driving, the deeper the part throttle, the more it goes lean until its getting close to fully open, then the power valve opens so its richer by full throttle. That's the way it should be.
idle mixtures are 1 turn out
As long as the screws are responsive, I don't get too hung up on this. Just keep track of the changes.
firstly where can i buy the idle feed restrictors , mine has allen key head ones.
its a kb carburetors carb? any opinions?
so the carb was built to suit and then dynoed so i dont want to get too over my head.
Sounds like buy and drill type.
The dyno, unless your dealing with someone very skilled and it has a load cell, isn't all that helpful for the part throttle and low speed stuff. If the carb was built to suit and then dynoed as you write, then it sounds like no tuning was done on the dyno other than jetting. Get a hold of the dyno logs if you can. If its a Dynojet brand, get the files so you can examine at your leasure on your computer. The others I don't know but they may also have programs to let you read the files.
Make one change at a time. Keep written notes as you already are doing, and you'll be fine. Worst case you return it to your baseline. Testing often includes a few dead ends.
Lets say you start with the slightly smaller IFRs, then make no other changes except tweaking the idle mix screws if needed. Go do your low speed tests, and then if driveable, see how it cruises at higher speeds.
If you're doing the main jets, don't change the IFRs. If you change the IFRs, don't change the main jets. Only exception would be if you wanted to put the jets back to the baseline.
Idle Air Bleeds are a finer adjustment than the Idle Restrictions. Even though they work hand in hand, just change one or the other.
Fuel Air Ratio to Load graph
How to download Dynojet Reader
Thinking about the .036 IFRs, something to consider
Relocating the Holley Idle Jet - racingfuelsystems.myfunforum.org