7029202 Build

[RonA]

Sorry for the long post but I want to be sure. I have Cliffs book and purchased my parts and kits from Cliff. Great book and quality parts. I also am doing a 7029203 carb for a different car but for now focusing on the 7029202 carb. Info on car :69 Camaro pace car restoration: th350 with stock converter,3.73 gears, stock cast intake, stock cast exhaust manifolds with factory 2 1/4 exhaust system, 041 heads 2.02/1.6 valves bowl blend only, block not decked with flat top pistons 10.1 comp, comp cam 12-210-2 268h .454/.454 218@.050 110 LSA.  I used recipe 2 as a guide. Idle tubes .039, down channel.052, upper air bleed .076, Lower air bleed .070, acc pump discharge .029, Main air bleed air horn .070/body .070, 69 jets, 42b rods, .135 needle seat, DA rods K hanger, float level .270, idle bypass air .086, idle screw holes .096, orange power piston spring APT adjusted to .068. Car ran ok not great had some control with idle screws but couldn't get the throttle blades low enough to stop nozzle drip. Tipped in apt 2200. got 11" vacuum.  Pulled carb and opened dcr to .055 no different. Pulled again and resized the lower idle air bleed down to .063 with the upper still at .076 to get to a .140 combination. Throttle shafts were bushed so I made sure the blades were centered. Started it up and had rumbling/backfiring thru the exhaust at idle and higher rpm and still nozzle drip. Pulled again to open idle bypass air to .096 and DCR to.059. Started and still a bit of ex backfire until choke came off and  I lowered the apt down. When warm the nozzle drip is gone. Can stall engine with the idle screws but not much change turning them out. Pulled a vacuum hose and rpm picks [rich] up yet tip in @2200 raises rpm [lean]. My next step is to check and resurface the airhorn in case of a vacuum leak. Cliff could you set me straight on what baseline I need to make as I probably went too far in some specs. Great forum !! Seems like a lot of smart helpful people on here. Sorry again for the long post. Thanks from Canada  Ron

[Cliff Ruggles]

If you were going to use 69 jets and 42B primary rods the stock MAB's should have also been retained.  It will be pretty lean everywhere with .070" MAB's, so right to start with I would go back to the stock MAB sizes, we have them here if you need some.

What size were the original idle tubes?  They are usually pretty big in those units and work very well with the stock IAB sizing, but the 110LSA Comp cam throws a monkey wrench into the deal.  I'm not fond of any of their stuff for that reason.  They are designed to give your engine the "bling" factor from lower idle vacuum, "lope" at idle, and more "attitude", not to improve scavenging, clean emissions, and greatly improved idle quality, throttle response off idle, and power in the "normal" driving range.........Cliff

[RonA]

Hi Cliff. I

[RonA]

Hi Cliff  Idle tube were .036. I ordered new tubes and main air bleeds this morning. I went with recipe #2 in the book. Do you have any other changes from those specs that I should do?  Thanks  Ron

[Cliff Ruggles]

Things will get better when you go back to the stock MAB sizes.  This will put more fuel in the engine right off idle, part throttle, and heavy part throttle.

Then all you have to do is to make sure it has adequate idle fuel and bypass air to stay on the idle system and full control with the mixture screws.......Cliff