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I am not sure on the emissions question but I can tell you the intake manifold is specific to the 4350 carb. They were also used on big block Fords in the 70s. You can find an adapter, Trans-Dapt 2199, that allows use of square bore carburetors on the spread bore intake. I put one on one of our 401s. The other option is go to a square bore intake like the Edelbrock Performer.
Why do you want to replace the 4350? Supposedly they are fine if the top is not warped. I suspect there's not much advantage of an aftermarket 4V carb over a properly functioning 4350, and there is no question that the 4350 will pass California smog if the rest of the emissions equipment is present and functioning. My understanding is that nothing is approved for California unless it has been certified as a replacement part, and has a CARB certification number. Thus you could avoid a lot of trouble by staying with the 4350.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
tgreese wrote:Why do you want to replace the 4350? Supposedly they are fine if the top is not warped. I suspect there's not much advantage of an aftermarket 4V carb over a properly functioning 4350, and there is no question that the 4350 will pass California smog if the rest of the emissions equipment is present and functioning. My understanding is that nothing is approved for California unless it has been certified as a replacement part, and has a CARB certification number. Thus you could avoid a lot of trouble by staying with the 4350.
4350 is great, if it’s not warped. Sometimes they can be milled a bit to fix warping.
But if you have to have another carb, Holley and edelbrock have smog legal carbs. Don’t have the model numbers on hand as I am on my phone. But you will need the adapter that is mentioned above.
Wonder if lapping, like we do with the timing covers, would work. Presuming you'd mill/lap the carb body to make the top surface flat. Or is it the base surface that warps?
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.
tgreese wrote:Wonder if lapping, like we do with the timing covers, would work. Presuming you'd mill/lap the carb body to make the top surface flat. Or is it the base surface that warps?
That might work but... I tried to keep 4350s going for a long time. I have taken 2-3 of them to build one working carb. What I have found is if they warp, it affects the top and the body. When I swapped a non-warped top on a body that had a warped top, it will still leak. Once I started using Holley Truck Avengers, I never looked back. I know people with them that have to go through emissions and they will pass. You might get questions on visual inspection.
Today, rather than buy a new carburetor for nearly $500 and another $50-200 for the adapter or manifold, I'd just pony up for a throttle body electronic fuel injection system. The Howell company has a CARB number for their Jeep fuel injection systems. Bolt-on kit. Aside from the other benefits of fuel injection (turn key starting in all weather, more reliable, simpler tuning), you can eliminate most of the smog plumbing and devices - IIRC you only need EGR, PCV, vapor recovery (for the tank only) and catalytic convertor. Should be very easy to pass smog with the Howell kit.
California inspection stations and FSJs are a hit and miss kind of thing. I got past the visual on my 76 401 Wagoneer with an Edelbrock 1406 by informing the tech that the carb was CARB approved and showed him the EO number. What he didn't know was that EO only applied if the carb replaced a GM unit. If you can possibly get that 4350 working properly and have all the proper hoses, delay valves, AIR pump etc in place, you can pass for a whole lot less than the cost of EFI. Another trick is to go to a testing station that doesn't have a 4-wheel dyno. Even if your jeep is part-time, put some drive slugs in the spindles and tell em it's full time. They will test at idle and 2500 RPM with no load, which makes it easier to pass.
1977 Cherokee Chief - The Blair Jeep Project III
A collection of parts flying in close formation