main reason im asking is because the exhaust pops when i rev it up and let off the gas. i have straight headers though, no exhust so idk whats goin on

 

also one more thing is i have a 1" phelonic 4 hole carb spacer i was thinking about putting on the moter, what do yall think and would it help or hurt in yalls opinon. sorry about all the questions but carburetors are confusing to me, a reply would be nice though lol
thanks anyways

 

anyone? any guesses or anythin?

 

i am not and engine builder and dont know nothing about anything. however i am looking at your list of goodies there and i would say your in trouble with any carb you have. huge cam, no compression, lousy intake, emission orientated carb. etc. no mention of gears, tire size, weight of vehicle, timing or other info.....you might be in for a learning curve. fwiw bobn

 

well its a street truck, 4.10 gears 40" tires, toploader 4 speed tranny (Low ratio), has to run off pump gas cam was free so had to use it anyways, dont know weight for shure but its in a 85 f150 shortbed 4x4

 

The popping when you let off is usually unspent fuel cooking off in the exhaust manifolds indication overly rich. That big cam coupled with lower compression is going to want to idle on the rich side. Might be difficult to dial in and tune that out while getting the combo to make decent power.

I always start tuning with the dizzy. I tend to run higher initial, even for street rides. Say 16 -20 initial and another 14-16 mechanical (total of 34) in by 3000. Then I take probably more time than necessary getting the floats perfect with stock carb jetting. I then move to the accelerator circuit and adjust the nut such that the least amount of pressure on the throttle emits a drip from the shooter. Almost always a 31 or a 35 size. Then primary jetting and finally secondary jetting all done on a lonely farm road or better yet the strip. Jet changes mean reassessing the floats to be certain they are still on and haven't changed.

Messing with a spacer is kept for after I'd have the combo dialed in as best as possible. Then I'd try it with the 4 hole or whatever and see if the truck picks up. That's really the only way to tell you if its a worth while addition.

 

ok thanks thats alot of helpful info, i got my timing set at 20 initial and 38 all in at 3000, that seems to be the perfect setting for what ive messed with it. i will make shure the floats are still set right too. barely running out the hole right? also i understand how to set the main jets cruise at about 2000 rpm and shut off and coast to a stop but how would i accuratly test secondary jets?

 

You can also set the floats with the bowls off. It will get you very close, and you won't have to worry about an engine FIRE! Just drain the carb, take off the bowls, flip them upside down and set the floats where the ridge is aligned with the bottom of the sight plug (when I say bottom, I mean if it where attached to the carb) Hope this makes sense.

Justin

 

ttt

 

I personally run my car with squared jetting and no PV's.

For a mostly street car I might run a pv in the front and none in the back so I'd start with the rear jet being the size of the front jet +8. Then tune from there (strip, dyno).