Holley pump cam help

[Ernest]

As mentioned before... if you're not comfortable modifying the metering block's IFR restrictors with 8-32 x 3/16" brass set screws to make them adjustable or cannot afford the billet metering blocks, the small wire method will work to reduce the surface area to help manage the fuel richness at idle.

Example picture(not mine):

 

[Bonnewagon]

help manage the fuel richness at idle

Ernest, I can get this thing to idle beautifully at 650 rpm, with 20" vacuum. But then when it goes into gear, it wants to die. If I raise the idle much, then all the other problems appear. So what they did was to idle at 1250, so that when in gear, it would stay running. But at that point, it is out of the idle circuit completely.

The transmission is a Turbo 400, which surprised me. But then I thought , those only came in either big cars, and/or behind big engines. I wonder if the torque converter is too low of a stall speed for a 350?

 

[Ernest]

Brand new carburetor, correct?

Possible vacuum leak... while idleing, spray carb cleaner around the base of the carburetor and around the intake manifold to cylinder head, check all vacuum lines/tubing as well, plug all ports on carburetor thats not needed.

Nothing wrong with putting a TH400 behind a SBC 350, unless its all you had to use, its not normaly needed unless its a 500+hp engine, but its a target master, its about as stock and low power daily driver engine as one can get.

 

[Pontiac455]

Ernest, I can get this thing to idle beautifully at 650 rpm, with 20" vacuum. But then when it goes into gear, it wants to die. If I raise the idle much, then all the other problems appear. So what they did was to idle at 1250, so that when in gear, it would stay running. But at that point, it is out of the idle circuit completely.

The transmission is a Turbo 400, which surprised me. But then I thought , those only came in either big cars, and/or behind big engines. I wonder if the torque converter is too low of a stall speed for a 350?

U mentioned when u changed the advance to manifold vac the rpm went up 100 rpm... I would be checking the advance plate.... It should increse the rpm alot more than 100.. I seen the advance plates siezed....S omething isnt right there....

 

[Bonnewagon]

its a target master, its about as stock and low power daily driver engine as one can get.

So a 600 cfm carb should be OK? The original was a 750. And I noticed the throttle plates were completely closed, so it was running on the idle circuit properly.

It should increse the rpm alot more than 100.

I thought so too. Using a Mighty-Vac, the advance does work. But hooking the dizzy to full manifold did not work well. I need to document the advance curve better, and get the part # on the carb so I know what is inside.

 

[Bonnewagon]

I looked at the part number on the air horn. It is an SL-600-VS 1012. Supposedly the primary jets are #68, air bleeds #70, power valve 6.5, nozzle #31.
The old 750 carb had #72 jets. If it was a Q-jet I would run #72 jets all day long.
My enginerd cousin says that 600 belongs on a 305.

 

[Ernest]

Target Master/Goodwrench 350 engines are low compression(8.5) with a stock profile hydraulic flat tappet and rated 260hp, a bit generous rating i think especially when that engine uses smog 76cc heads and suggested with headers .... either way, the 600cfm carburetor is plenty, the 750cfm is too large for your application, its better suited on engines producing 350+ hp IMO.

 

[Bonnewagon]

Target Master/Goodwrench 350 engines are low compression(8.5) with a stock profile hydraulic flat tappet and rated 260hp,

That is the first I have heard of the compression, thanks for that. But it makes me wonder why when we bumped the timing to 12° it was hard to start, like it was too far advanced.

 

[Bonnewagon]

Another thing I noticed was that no one set the secondary fuel bowl height. It looks to be very high through the window. Would that have a path to flood the carb from the secondary side?

 

[Bonnewagon]

Update: I lowered the secondary fuel bowl level. That helped a lot. But I then had to raise the primary fuel bowl level. Then we used a base idle of 1000 rpm to see what happens when you put it in DRIVE. Well, it dropped down to 450/500 rpm, stabilizing at 510. So just putting it in gear caused a 500 rpm drop, so idling at 650, it drops so much, the engine dies. While in gear, brake pressed, I upped the idle speed. It would not get past 550 no matter how much I raised the idle. It felt like the trans was locking the engine down. I then adjusted the idle up and down, and found the sweet spot, at 950rpm, where the engine did not die in gear, the vacuum was 18", and there was no timing advance occurring. Driving it, the engine roared, did not die at a stop sign, but still idled rough. WTF?!?