Originally Posted by 4406bbl
What should a stock set of #41 plates measure for idle restrictions, and main jet? I have a holley book but as we know the new 440 #34-35 plates made today are not the same as what was installed in 1970.

Holley book shows #41
.033 idle
.070 main jet restiction
Kinda find that main size small for a 1-3/4 holley barrel, and dyno tests I have saved thru the years show .079-.083 to net a 13-1 afr, still lean. An 850 holley, same barrels, uses a #80 jet, amd a power valve. So are new # 41 plates correct or too small?

Here is a list of the plates in my 340 carbs . The last 2 carbs are the replacement carbs. These were all pined.

LIST # DATE APP PLATE IAB HSB T JET D KILL BLEED IFR
4789 490 340 F 41 0.052 0.039 .086 .072 0.046 0.037
4789 500 340 F 16 0.052 0.039 .067 .079 0.047 0.028
4789 890 340F 41 0.052 0.039 .085 .073 0.045 0.037
4790 500 340 R 41 0.052 0.039 .086 .072 0.046 0.037
4790 850 340R 41 0.052 0.039 .085 .072 0.045 0.037
4790 3518 340 F 41 0.068 0.027 .086 .072 0.047 0.037
4790 3518 340 R 41 0.068 0.027 .086 .072 0.046 0.037



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