Ok, this is a long one. The xecute-ive summary first:
Chart 1:
Chart 2:
The jet sizes for Holley Webers are:-
103 cc/min=105 microns, or 41.34 thou
128 cc/min=110 microns, or 43.31 thou
152 cc/min=115 microns, or 45.28 thou
178 cc/min=120 microns, or 47.24 thou
201 cc/min=125 microns, or 49.21 thou
225 cc/min=130 microns, or 51.18 thou
251 cc/min=135 microns, or 53.15 thou
275 cc/min=140 microns, or 55.12 thou
298 cc/min=145 microns, or 57.09 thou
325 cc/min=150 microns, or 59.06 thou
346 cc/min=155 microns, or 61.02 thou
375 cc/min=160 microns, or 62.99 thou
400 cc/min=165 microns, or 64.96 thou
425 cc/min=170 microns, or 66.93 thou
450 cc/min=175 microns, or 68.90 thou
475 cc/min=180 microns, or 70.87 thou
525 cc/min=185 microns, or 72.83 thou
Chart 3:
The jet sizes for Holley 2300/4150/4160/4165/4175/4500 carbs are:-
Red indicates the best estimate figures. HolleyWeber and Holley 2300/4150/4160/4165/41754180/4500 jets are not the same, and I've not seen all the data for all jets 40 to 59. Smaller jets have more headloss, and flow much worse than there area would suggest. Those from 60 to 100 are form the Barry Grant © 1997, catalogue
123 cc/min or 40 thou nominal, 40 call size jet
129 cc/min or 41 thou nominal, 41 call size jet
136 cc/min or 42 thou nominal, 42 call size jet
142 cc/min or 43 thou nominal, 43 call size jet
149 cc/min or 44 thou nominal, 44 call size jet
157 cc/min or 45 thou nominal, 45 call size jet
164 cc/min or 45 thou nominal, 46 call size jet
171 cc/min or 47 thou nominal, 47 call size jet
178 cc/min or 48 thou nominal, 48 call size jet
185 cc/min or 48 thou nominal, 49 call size jet
192 cc/min or 49 thou nominal, 50 call size jet
198 cc/min or 50 thou nominal, 51 call size jet
205 cc/min or 52 thou nominal, 52 call size jet
212 cc/min or 52 thou nominal, 53 call size jet
221 cc/min or 53 thou nominal, 54 call size jet
230 cc/min or 54 thou nominal, 55 call size jet
239 cc/min or 55 thou nominal, 56 call size jet
248 cc/min or 56 thou nominal, 57 call size jet
257 cc/min or 57 thou nominal, 58 call size jet
267 cc/min or 58 thou nominal, 59 call size jet
285 cc/min or 60 thou nominal, 60 call size jet
298 cc/min or 60 thou nominal, 61 call size jet
311 cc/min or 61 thou nominal, 62 call size jet
325 cc/min or 62 thou nominal, 63 call size jet
341 cc/min or 64 thou nominal, 64 call size jet
357 cc/min or 65 thou nominal, 65 call size jet
374 cc/min or 66 thou nominal, 66 call size jet
392 cc/min or 68 thou nominal, 67 call size jet
411 cc/min or 69 thou nominal, 68 call size jet
429 cc/min or 70 thou nominal, 69 call size jet
448 cc/min or 73 thou nominal, 70 call size jet
470 cc/min or 76 thou nominal, 71 call size jet
492 cc/min or 79 thou nominal, 72 call size jet
517 cc/min or 79 thou nominal, 73 call size jet
542 cc/min or 81 thou nominal, 74 call size jet
566 cc/min or 82 thou nominal, 75 call size jet
587 cc/min or 84 thou nominal, 76 call size jet
615 cc/min or 86 thou nominal, 77 call size jet
645 cc/min or 89 thou nominal, 78 call size jet
677 cc/min or 91 thou nominal, 79 call size jet
703 cc/min or 93 thou nominal, 80 call size jet
731 cc/min or 93 thou nominal, 81 call size jet
765 cc/min or 93 thou nominal, 82 call size jet
795 cc/min or 94 thou nominal, 83 call size jet
824 cc/min or 99 thou nominal, 84 call size jet
858 cc/min or 100 thou nominal, 85 call size jet
890 cc/min or 101 thou nominal, 86 call size jet
923 cc/min or 103 thou nominal, 87 call size jet
952 cc/min or 104 thou nominal, 88 call size jet
987 cc/min or 104 thou nominal, 89 call size jet
1014 cc/min or 104 thou nominal, 90 call size jet
1080 cc/min or 105 thou nominal, 91 call size jet
1150 cc/min or 105 thou nominal, 92 call size jet
1200 cc/min or 105 thou nominal, 93 call size jet
1260 cc/min or 108 thou nominal, 94 call size jet
1320 cc/min or 118 thou nominal, 95 call size jet
1375 cc/min or 118 thou nominal, 96 call size jet
1440 cc/min or 125 thou nominal, 97 call size jet
1500 cc/min or 125 thou nominal, 98 call size jet
1570 cc/min or 125 thou nominal, 99 call size jet
1640 cc/min or 128 thou nominal, 100 call size jet
Topic name change from 'Benny and the Jets' to something more sensible!
Jets for #5200 Holley/Weber and Weber 32/36 carbs:
5.5 times the estimated net hp at the flywheel gives the Total cc per minute required. Add primary and secondary jets together to get the result.
Eg.1 32/36 with 65 Idle, 150 primary, 135 secondary. From the chart RougeS posted, at http://members.cox.net/gork1/jetsize.gif
Please note that these are stamped in either Microns ( not mm , but mm/100), a silly metric measurement, or cc/min, a silly metric measurement. But hey, silly metrics are okay as long as the help me jet my in-line six right!
Say you hope to have 125 hp at the flywheel of your new 200 rebuild, and you need to jet it to suit. Well, just take that 125, and times it by 5.5, and this gives 687.5 cc/min jetting required. Since the existing jets are 150 and 135, then the flows are 325 plus about 251 cc/min, or 576 total. I'd say that was to small, because 576 divided by 5.5 is about 105 hp. So pump up the jet size on primary and secondary to 155 and 140. That's, from RougeS's chart, about 621 cc/min from the 346 and 275 cc/min readings these jet give. 621 divided by 5.5 is about 113 hp.
Still to small for 125hp. Go to 160 and 145, at 375 and 298 cc/min respectively, gives 673 cc/min. That's 122 hp, according to my theory
Jets for #2300 Holley 350 cfm 2-bbl carbs:
3.7 times the estimated net hp at the flywheel gives the Total cc per minute required. Add both jets together to get the result.
Eg.1 350 cfm Holley on a little 2.0 Liter Pinto with a cam, head mods, and headers gives 130 hp at 6000 rpm. Jets needed are 56 jets, rated at 239 cc/min from another chart. (Note well. Holley and Holley Weber jets are not the same. You can't use this chart from the Holley/Weber.) The bulk flow from both jets is 478 cc/minute, or enough for 129 hp from my formula. Below this post is a long, strung out chart which shows you the flow numbers for varoius Holley jets from 40 to 100.Part of it is ex Barry Grants catalogue, those from 40 to 59 are extrapolated.
Please note that these are not stamped in thou, although that is close for the 40 to 67, after this point, the jet is much bigger inside than 100 for a 100 jet. In fact, its 128 thou.
Say you hope to have 155 hp at the flywheel of your new 200 rebuild, and you need to jet it to suit. Well, just take that 155, and times it by 3.7, and this gives 573.5 cc/min jetting required. What size jets do you need? Well, the 60 jet discharges about 285 cc/min, or 570 cc/min total. Perfect!
Jets for #2300 Holley 500 cfm 2-bbl carbs:
5.5 times the estimated net hp at the flywheel gives the Total cc per minute required. Add both jets together to get the result.
Eg.1 500 cfm Holley on a little 2.0 Liter Pinto with a cam, head mods, and headers gives 138 hp at 6500 rpm. Jets needed from the dyno tuning session were 74 jets, rated at a massive 542 cc/min each from another chart. In actuality, thats 7.86 cc/min of jet per HP , very, very big. Too big in fact. The bulk flow from both jets is 1084 cc/minute, or enough for 197 hp from my formula. This is wrong. A couple of 66 jets, yielding 374 cc/min each, is more than adequate to compensate for a carb flow area 1.429 times larger than a 350 cfm Holley. Accordingly, the formulae has been changed to this 5.5 ratio. Anything else over sizes the jets for 500 Holleys. There is much anecdotal evidence to prove this.(Note well. Holley and Holley Weber jets are not the same. You can't use this chart from the Holley/Weber.) Below this post is a long, strung out chart which shows you the flow numbers for various Holley jets from 40 to 100. Part of it is ex Barry Grants catalogue, those from 40 to 59 are extrapolated.
Please note that these are not stamped in thou, although that is close for the 40 to 67, after this point, the jet is much bigger inside than 100 for a 100 jet. In fact, its 128 thou.
Say you hope to have 220 hp at the flywheel of your new 250 rebuild, and you need to jet it to suit. Well, just take that 220, and times it by 5.5, and this gives 1210 cc/min jetting required. What size jets do you need? Well, the 77 jet discharges about 615 cc/min, or 1230 cc/min total. Perfect for 224 hp!
Jets for #4150/4160 Holley390 to 850 cfm 2-bbl carbs with replaceable rear jets(34-6 kit):
Formulae 1: 5.5 times the estimated net hp at the flywheel gives the Total cc per minute required. Add both jets together to get the result. (Suites 14.7:1 stoichometric ratio at wide open throttle).
Formulae 2: 6.6 times the estimated net hp at the flywheel gives the Total cc per minute required. Add both jets together to get the result. (Suites 12.5:1 maximum power ratio at wide open throttle).
Eg.1 390 cfm Holley on a little 2.3 Liter Pinto with a cam, head mods, and headers gives 135 hp at 6000 rpm. Jets needed from the dyno tuning session were two 48's for the primaries, and two 50's for the secondaries, on a 4160 carb converted to replaceable secondary jets. Taken together, thats about 178 cc/min each from the primaries, and 192 cc/min from each secondary jet, for a total or 740 cc/min. 5.5 factor, again.(Note well. Holley and Holley Weber jets are not the same. You can't use this chart from the Holley/Weber.) Below this post is a long, strung out chart which shows you the flow numbers for various Holley jets from 40 to 100. Part of it is ex Barry Grants catalogue, those from 40 to 59 are extrapolated.
Please note that these are not stamped in thou, although that is close for the 40 to 67, after this point, the jet is much bigger inside than 100 for a 100 jet. In fact, its 128 thou.
Say you hope to have 240 hp at the flywheel of your new 200 2V 250 headed rebuild, and you need to jet it to suit. Well, just take that 240, and times it by 5.5, and this gives 1320 cc/min jetting required. What size jets do you need? Well, the 330 cc/min per jet is satisfied by 62's and 65 secondaries, for 311 and 357 cc/min, or 1336 cc/min total. Perfect for 243 hp!
Eg.2 Say that someone imports an Aussie 250 x-flow, and wacks it into a Fox Mustang. He gets blown off by a 5.0 Mustang, so he decides to use a 750 Holley 4-bbl, 4-bbl intake, and works it up to spin to 7800 rpm, and hopes to get 375 hp. He jets up a 750 cfm vac sec 4160 carb, with a 34-6 kit, and finds 72 mains, and 81 secondaires are it. This, in bulk cc/min flow per hp, is 6.6 times the 375 hp figure. Bulk area of primaries is (492 + 731)*2, or 2446 cc/min. Thats about 371 hp by my formulae. In fact, this is the jetting needed for a modified street and strip 351 Cleveland 2V, making 375 hp. The premise I make is that the jetting is the same as long as the hp is the same. Fine tunning will be needed for the truth to come out.
Chart 1:

Chart 2:
The jet sizes for Holley Webers are:-
103 cc/min=105 microns, or 41.34 thou
128 cc/min=110 microns, or 43.31 thou
152 cc/min=115 microns, or 45.28 thou
178 cc/min=120 microns, or 47.24 thou
201 cc/min=125 microns, or 49.21 thou
225 cc/min=130 microns, or 51.18 thou
251 cc/min=135 microns, or 53.15 thou
275 cc/min=140 microns, or 55.12 thou
298 cc/min=145 microns, or 57.09 thou
325 cc/min=150 microns, or 59.06 thou
346 cc/min=155 microns, or 61.02 thou
375 cc/min=160 microns, or 62.99 thou
400 cc/min=165 microns, or 64.96 thou
425 cc/min=170 microns, or 66.93 thou
450 cc/min=175 microns, or 68.90 thou
475 cc/min=180 microns, or 70.87 thou
525 cc/min=185 microns, or 72.83 thou
Chart 3:
The jet sizes for Holley 2300/4150/4160/4165/4175/4500 carbs are:-
Red indicates the best estimate figures. HolleyWeber and Holley 2300/4150/4160/4165/41754180/4500 jets are not the same, and I've not seen all the data for all jets 40 to 59. Smaller jets have more headloss, and flow much worse than there area would suggest. Those from 60 to 100 are form the Barry Grant © 1997, catalogue
123 cc/min or 40 thou nominal, 40 call size jet
129 cc/min or 41 thou nominal, 41 call size jet
136 cc/min or 42 thou nominal, 42 call size jet
142 cc/min or 43 thou nominal, 43 call size jet
149 cc/min or 44 thou nominal, 44 call size jet
157 cc/min or 45 thou nominal, 45 call size jet
164 cc/min or 45 thou nominal, 46 call size jet
171 cc/min or 47 thou nominal, 47 call size jet
178 cc/min or 48 thou nominal, 48 call size jet
185 cc/min or 48 thou nominal, 49 call size jet
192 cc/min or 49 thou nominal, 50 call size jet
198 cc/min or 50 thou nominal, 51 call size jet
205 cc/min or 52 thou nominal, 52 call size jet
212 cc/min or 52 thou nominal, 53 call size jet
221 cc/min or 53 thou nominal, 54 call size jet
230 cc/min or 54 thou nominal, 55 call size jet
239 cc/min or 55 thou nominal, 56 call size jet
248 cc/min or 56 thou nominal, 57 call size jet
257 cc/min or 57 thou nominal, 58 call size jet
267 cc/min or 58 thou nominal, 59 call size jet
285 cc/min or 60 thou nominal, 60 call size jet
298 cc/min or 60 thou nominal, 61 call size jet
311 cc/min or 61 thou nominal, 62 call size jet
325 cc/min or 62 thou nominal, 63 call size jet
341 cc/min or 64 thou nominal, 64 call size jet
357 cc/min or 65 thou nominal, 65 call size jet
374 cc/min or 66 thou nominal, 66 call size jet
392 cc/min or 68 thou nominal, 67 call size jet
411 cc/min or 69 thou nominal, 68 call size jet
429 cc/min or 70 thou nominal, 69 call size jet
448 cc/min or 73 thou nominal, 70 call size jet
470 cc/min or 76 thou nominal, 71 call size jet
492 cc/min or 79 thou nominal, 72 call size jet
517 cc/min or 79 thou nominal, 73 call size jet
542 cc/min or 81 thou nominal, 74 call size jet
566 cc/min or 82 thou nominal, 75 call size jet
587 cc/min or 84 thou nominal, 76 call size jet
615 cc/min or 86 thou nominal, 77 call size jet
645 cc/min or 89 thou nominal, 78 call size jet
677 cc/min or 91 thou nominal, 79 call size jet
703 cc/min or 93 thou nominal, 80 call size jet
731 cc/min or 93 thou nominal, 81 call size jet
765 cc/min or 93 thou nominal, 82 call size jet
795 cc/min or 94 thou nominal, 83 call size jet
824 cc/min or 99 thou nominal, 84 call size jet
858 cc/min or 100 thou nominal, 85 call size jet
890 cc/min or 101 thou nominal, 86 call size jet
923 cc/min or 103 thou nominal, 87 call size jet
952 cc/min or 104 thou nominal, 88 call size jet
987 cc/min or 104 thou nominal, 89 call size jet
1014 cc/min or 104 thou nominal, 90 call size jet
1080 cc/min or 105 thou nominal, 91 call size jet
1150 cc/min or 105 thou nominal, 92 call size jet
1200 cc/min or 105 thou nominal, 93 call size jet
1260 cc/min or 108 thou nominal, 94 call size jet
1320 cc/min or 118 thou nominal, 95 call size jet
1375 cc/min or 118 thou nominal, 96 call size jet
1440 cc/min or 125 thou nominal, 97 call size jet
1500 cc/min or 125 thou nominal, 98 call size jet
1570 cc/min or 125 thou nominal, 99 call size jet
1640 cc/min or 128 thou nominal, 100 call size jet
Topic name change from 'Benny and the Jets' to something more sensible!