Dyno Results
#61
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Joined: Nov 2004
Posts: 14,097
Likes: 3,687
From: On A Dirt Floor
Without a wideband I go #2 sizes jet richer than best performance and check my plugs here and there for specs of aluminum. Without mag glass they usually appear like pepper specs.
With a new to me carb I jet richer for first jet change. #2 each time (if going bigger or smaller)while keeping the carb's factory prim to secondary jet spread the same.
Only change to this is if 1st or 2nd run is bad lean, then I jump a bunch. Doesn't happen much cause a properly chosen carb won't be too far off.
With a new to me carb I jet richer for first jet change. #2 each time (if going bigger or smaller)while keeping the carb's factory prim to secondary jet spread the same.
Only change to this is if 1st or 2nd run is bad lean, then I jump a bunch. Doesn't happen much cause a properly chosen carb won't be too far off.
#63
#67
#68
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Joined: Sep 2006
Posts: 482
Likes: 0
From: Indianapolis, IN
been reading you all threads on jets...Ive been running 78 and 86 on my 496 stroked, alm. heads, deamon 750 and there still black rich.6.5 valve primary only.. maybe I got something else going on .. any thoughts??
#69
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Joined: Nov 2004
Posts: 14,097
Likes: 3,687
From: On A Dirt Floor
Jetting is more dependant on the carburetor itself. Do not follow jetting from another part# carb.
And then of course the motor build up and use itself.
Anyone notice that on most Holley's, most 600cfm+ carb will have jets in the 60's , most 700+cfm carbs will have jets in the 70's, 800+'s in the 80's, 900+'s in the 90's ???? LOL. Ka winky dinky huh ? LOL.
Smaller venturi's and throttle blade size with same booster pulls more fuel for same given amt of air pulled thru.
Edit in: I see you have a Barry Grant carb. You really can't compare jetting and other things with a BG vs an 'equivalent' Holley.
And then of course the motor build up and use itself.
Anyone notice that on most Holley's, most 600cfm+ carb will have jets in the 60's , most 700+cfm carbs will have jets in the 70's, 800+'s in the 80's, 900+'s in the 90's ???? LOL. Ka winky dinky huh ? LOL.
Smaller venturi's and throttle blade size with same booster pulls more fuel for same given amt of air pulled thru.
Edit in: I see you have a Barry Grant carb. You really can't compare jetting and other things with a BG vs an 'equivalent' Holley.
Last edited by SB; 07-15-2014 at 07:58 PM.


