sigtauenus
Active Member
I can't believe its July and I'm still screwing with this. Winter was rough, weather too shitty to drive, and spring was a blur. I think I've flown 25,000 miles in the past 2 months.
Anyhow. To the issue:
Pulled the jets on the carb tonight.
What I'm working with is a 5.0 short block, ported 289 heads with 351W valves, long tube headers, shelby high-rise intake, holley 725 list 4118 (4150 with vac sec).
Car starts and idles just fine. rev's fine. drive's fine except for one thing.
I pull out in 1st, all is good, I shift into 2nd, push on the gas, and the engine stumbles.
With the car idling, the air stinks of gas. Plugs are a dark grey and wet with gas. I know you need to read them after cruising, but the car still shouldn't be running this rich at idle.
Floats are set where you can just see the fuel at the threads and it dribbles out if you rock the car.
Timing is set at 10* with 35* total at 3500 rpm.
Primaries are a 62, secondaries are a 71 jet size.
Idle is set at around 625-650 and it idles smooth.
Idle mixture was set by leaning it out until the vacuum dropped then turning the screw back towards rich 1/4 turn or so. Vacuum is reading around 19 in.
I know the carb is big for the engine, but its a 68 shelby replacement carb, and my engine flows better than the stock 302 did, so I should be able to make this work.
I have no idea what the original jets were, and nothing to reference.
Does 62 primary sound like too much?
I plan on just biting the bullet and buying a holley tuning kit, but would still like to have some assessment on where I'm at. I plan on initially dropping down to 60 and see what happens.
I'm more concerned about the stumble than I am the richness at idle, but I'm pretty sure the jets are responsible for both.
Suggestions?
Anyhow. To the issue:
Pulled the jets on the carb tonight.
What I'm working with is a 5.0 short block, ported 289 heads with 351W valves, long tube headers, shelby high-rise intake, holley 725 list 4118 (4150 with vac sec).
Car starts and idles just fine. rev's fine. drive's fine except for one thing.
I pull out in 1st, all is good, I shift into 2nd, push on the gas, and the engine stumbles.
With the car idling, the air stinks of gas. Plugs are a dark grey and wet with gas. I know you need to read them after cruising, but the car still shouldn't be running this rich at idle.
Floats are set where you can just see the fuel at the threads and it dribbles out if you rock the car.
Timing is set at 10* with 35* total at 3500 rpm.
Primaries are a 62, secondaries are a 71 jet size.
Idle is set at around 625-650 and it idles smooth.
Idle mixture was set by leaning it out until the vacuum dropped then turning the screw back towards rich 1/4 turn or so. Vacuum is reading around 19 in.
I know the carb is big for the engine, but its a 68 shelby replacement carb, and my engine flows better than the stock 302 did, so I should be able to make this work.
I have no idea what the original jets were, and nothing to reference.
Does 62 primary sound like too much?
I plan on just biting the bullet and buying a holley tuning kit, but would still like to have some assessment on where I'm at. I plan on initially dropping down to 60 and see what happens.
I'm more concerned about the stumble than I am the richness at idle, but I'm pretty sure the jets are responsible for both.
Suggestions?