4150, huge stumble and dies in gear.

[Cope]

So I was having an issue with my old 750 DP and didn't have the parts to rebuild it.
Instead I pulled the freshly rebuilt 950 pro form off my 512 CI stroker and slapped it on my 318....
I did change the Jets to the ones out of the 750. 73F And 79R I think. I also pulled the 6.5 power valve and swapped it out for the plug in the 950. In theory this sucker should be running but NOOOO. it has a huge stumble off idle and dies when I try to drop it in gear.
I also changed out the pump cam and squirters to the ones off the 750. (Pink cam, hole #1 and 28 squirter front and rear)

The thing sounds mean as hell and the one little drive I got in it once passed the stumble it was a rocket!

My AFR gauge reads 13.8-14 ish at idle (in nutral) I'm pulling 19 inches of vacuum in nutral.

Fuel PSI, just under 6 pounds. Mechanical gauge and regulator.

Vacuum advance is plugged but I have tried it both ways.

No vacuum leaks found when spraying.

And carb guys got a idea as to how to make this much carb run on this pansy motor?

The motor dose have long tube headders, and high rise dual plane. MSD and new plugs, wires.

 

[72bluNblu]

What's your AFR doing off idle? Tuning that big of a carb down for a 318 is gonna be a pain in the butt. Sounds like a pretty mild 318 too? It would be easier to tune a 500 for it than a 950.

 

[yellow rose]

You are probably going to need a 37 squirter to get the bog out. That's a pretty big Venturi if it's a 950.

 

[Cope]

AFR seems to stay good with snaps in nutral. Response is good in nutral also. Just dies in gear.

I got a 38 laying around, I toss that in and see.

My DB timimg light is at our shop and the car is at home so not sure on timing but the dizzy won't twist so it ain't moved.

The car burned 2 plug wires the other day and backfired hard. I didn't feel like getting new gaskets so I figured what the hell, let's see if this works. And boy it screams if I can get it in drive and past the stumble.
The PV is new and was not in the 750 for the back fire. I think the 750 blew the base gasket and no where around me sells em.

I will try the 38s.

 

[AJ/FormS]

19 inches in neutral. What is the idle-timing and idle rpm?
19 sounds like a stock or near stock cam.
For a stock long-block 318;
>Be sure the secondaries are closed up tight,and that the PCV system is hooked to the front of the carb,and working, and that the power brake booster is not sucking air.
Then,for the dies going into gear;
>The only circuit that is supposed to be operating at idle, is the slow-speed circuit. This is a combination of fuel level,transfers slots, and mixture screws. I have a feeling your T-port sync is messed up. With a stock teener; I would start with no VA,and 12* of idle timing, and idle speed up to 650/700N, and the mixture screws at 1T out. But with the big throttle valves, I might have to idle at 700 to prevent a tip-in sag.Get the AFR a little richer than 13.8/14, by opening the curb idle. If the rpm goes too high retard the timing.If too slow advance it a tad.
Alternatively,you can zero in on the correct T-port setting by removing the carb and flipping it over and readjusting the curb-idle so that that the transfer-slot exposure is square to a little taller than wide,and the resetting the mixture screws to 3/4 t out. Then bolt it back on.After this do not reset the curb idle screw.Do not reset the curb idle screw. Set the idle speed with idle-timing and idle-air bypass, although there is a great chance that the idle speed will already be too high with the speed screw set this way. This is because of the amount of air sneaking around all those huge airvalves. You may have to clamp the PCV closed to actually reduce idle-air bypass, or else the idle-timing will just become too low. And when the timing gets to zero advance, well you know that is just gonna be soooooo lazy.lol.
You need to get the engine to idle down to under 700, so that the airspeed past the low-speed circuit ports doesn't tank when the TC drags the idle down yet further. In other words you need to deactivate the TC, by slowing it down, allowing it to slip.
Try this, the next time the car is moving; as you come rolling to a stop, put the tranny in neutral, and then back into gear, and accelerate a little. Then repeat;each time coming closer and closer to a stop.Watch the AFr.
But
If the cam is a little bigger (for a teener), the C/R is high, the idle timing is 22, and the rpm is 1000, then 19" starts to sound sorta normal.In this case the 950 s still way too big, and the airspeed drop when going into gear is deadly. And still, you are gonna need a bigger PV,sooner or later, an smaller MJs.
>But you called it a "pansy motor", so Ima thinking she's a stocker, and I can't figure out why you would want to put a 950 on it; the airvalves are just too big. Vacuum starts to drop almost the instant you step on the gas.
Then for the stumble;
Your accelerator pump better be working real good.
Good luck,fella

 

[72bluNblu]

AFR seems to stay good with snaps in nutral. Response is good in nutral also. Just dies in gear.

I got a 38 laying around, I toss that in and see.

My DB timimg light is at our shop and the car is at home so not sure on timing but the dizzy won't twist so it ain't moved.

The car burned 2 plug wires the other day and backfired hard. I didn't feel like getting new gaskets so I figured what the hell, let's see if this works. And boy it screams if I can get it in drive and past the stumble.
The PV is new and was not in the 750 for the back fire. I think the 750 blew the base gasket and no where around me sells em.

I will try the 38s.

You're like an hour from Summit's Sparks warehouse. If you order a gasket kit right now you'll probably have it tomorrow.

 

[540slant6]

Wow, lot of carb for a tenner. I went from a 600 CFM to a 625 CFM carter and she loves it! My teener is a bit more than stock though. Those small valves won't like that big CFM outta the hole.