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curtis73
03-23-2007, 05:44 PM
I have a marine Holley 650 SP, 4160 spreadbore for my vortec 350. Its stock with a stock cam and heads.
Anyone know what a good jetting would be to start with?
67weimann
03-23-2007, 06:07 PM
Start with what the carb comes jetted with from the factory.
centerhill condor
03-23-2007, 06:16 PM
elevation makes a difference. the condor is from corpus christi and the plugs are black after 100 hours. 'bout 1000' elevation difference.
spectras only
03-23-2007, 06:30 PM
lots of info here > http://www.mortec.com/carbs.htm
SmokinLowriderSS
03-24-2007, 05:50 AM
Take the list # from the air horn and go down the mortec link, and check the carb for the orriginal jets, start from there. It is rare that a holley does not run well just outta the box as set by the factory so they get em pretty close. Set the idle mixture screws about 2 turns open from seated.
curtis73
03-25-2007, 04:20 PM
Sweet, thanks!
Moneypitt
03-25-2007, 04:37 PM
I thought the spread bore carbs were 4165 (DP)/4175 (SP) series.......MP
SmokinLowriderSS
03-25-2007, 05:06 PM
4160's are a vac seccondary, square-bore, basically vac sec of the 4150 DP.
4165's & 4175's are a vac secc spread bore Q-jet replacement.
Both usually elec choke equipped.
Man has holley got a lot of carb models. :confused:
Moneypitt
03-25-2007, 05:18 PM
4165 is a double pumper spreadbore, the 4175 is the vac secondary version....Both spread bores and also there are list numbers for T Quad replacements for the Mopars........MP
SmokinLowriderSS
03-25-2007, 08:15 PM
Thx for the help MP. :)
shockwaveharry
03-25-2007, 08:24 PM
65-ish will probably be just fine if that's not what's in there already. My disclaimer states that final jet selection is based on proper dyno tuning/plug reading, but thye reality is close will be just fine. You'd have to be way off on the jets to cause any problems so don't sweat it on this one.