anyone modify the LOW SPEED JET on a clone

[1992suburban]

so I was thinkin when I instal header and air flter upgrade I will need to ReJet the carb. Main @ .037-.038" low speed (might not need to adjust) but I may..

and whats with the 140 emulsion tube. who has done this????

 

[modelengineer]

Usually you don't have to change the idle jet, since the stock filter and pipe offer little restriction at idle. It's when you rev it up that it's really different, so changing the main jets is more important.

For example on my GS engine I'm upgrading to UNI pod filters and straight pipe exhaust and I'm going from:
17.5 - 60 - 130
to
20.0 - 65 - 145

You can see the main jet changes the most.

 

[1992suburban]

what do those numbers mean?? 17.5 - 60 - 130???

I never jetted one before

 

[theo]

Before you change jets do a engine chop and check the plug color.