tuning carbs

hybrid_58

New Member
Hello,

New member here. Just picked up a 1960 impala with the 348 tri power. Runs fairly well but wants to leave a huge trail of black smoke whenever I kick it in to the secondary carbs. This and the fact that I got about 10 miles to the gallon on the trip home from picking it up tells me that I may need to do some carb tuning. What kind of adjustments do the secondary carbs have that would let me lean those out somewhat? Float level? Acc pump adjustment?

Thanks
Todd
 

Fathead Racing

Well Known Member
Supporting Member 7
Carbs

Yes, float levels will make or break you. Look at the jet sizes also and make sure that someone has not tampered with the correct sizes. By all means rebuild the carbs, a worn needle and seat will have the engine running rich! Fuel pump pressure should not be over 5 psi. Besides making sure that the throttle blades are opening fully when you mat the throttle you should be good to go.:cheers
 

bobs409

 
Administrator
Too large of secondary jets would do it. Maybe this black smoke is just carbon? Since you just bought it, maybe the past owner putt-putted around with it??? Probably not but just wanted to throw that out there...

And one very obvious one is the choke. Make sure the plates are fully opened when warmed up.
 
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