UPDATE. Re afr cruise tuning on HP1000

[CDN]

Thanks to all who gave input on my earlier post It all helped cruise AFR now in 14’s

Custom built HP1000 r80514 for track use performed great no issue
Racing days over want street car cruise was very rich always in the 12’s off idle

475ci BBC pump gas 260@.050 cam 5 speed manual 4:30 rear Chevelle
As raced 83/91
Iab .067 mab .028
Ifr .035 bottom
PVCR .070
BLP BASEPLATE & metering blocks
No T slot restriction
Mains starting at 2000

NEW Tune
Down 3 on primary jet to .080
IAB .075
Mab .025

IFR .033 bottom
T slot squared off floats 1/3 up

IDLES at 1050rpm.
AFR 14.2
Cruise between 1700 -2100
AFR. 14.5

Main come in a bit later when I went to smaller MAB
Higher cruise 14.2. 65/70 mph rpm 220-2400
In 5 th gear at 60 mph with very light throttle pressure dips into 15’s

So far no driveability issue no detonation
Cold starts definite need alot of feathering till it warms up

I can richen idle with mixture screws to 13.9 but seems to be OK at 14.2
Im very surprised it idles that lean
Fast afr meter dual sensors both similar

Welcome any and all comments never touched mu emulsion settings .028 plug .028 plug plug
Not sure if any reason to change

Should I have gone with .031 IFR AND .070 IAB compared to the 033 ifr & .075 iab would that be leaner or about same

[rgalajda]

Well that is great progress. It would be interesting to see how it responds to .031 and .070

[CDN]

It took a long time to get to this point lots of ups and downs
There were times I doubted the afr meter etcetc and times I could not repeat the numbers ( my car takes ling time to fully warm up so had to make sure it was always at least 180
What i dont know does the .025 mab over the .028 makeup enough to cover the primary jet reduction ?? Have not done enough WOT high gear runs yet to check afr
It was 12.5 at WOT on dyno safe but pbly could be leaner ??
For now just focusing on street performance

[Right hand drive]

I'm assuming the change to .031"/.070" would yield similar afr numbers, maybe slightly leaner. It would be interesting if it affected the stability of afr readings ie less fluctuations or more than currently?
The .031" ifr would slightly change pressure differentials upstream and .070" iab carry trans slot fuel slightly further into throttle opening.

[CDN]

Thanks for that insight, had not thought of that Currently the afr is very stable im going to leave as is and get more time / data on it before I make a change but Not sure if I can expect to get it much leaner and not have driveability issues

[Right hand drive]