My maverick is cursed

I will be putting in the hei dizzy today just to see what happens. I sure hope thats the issue, I would be more then happy to run out and buy a new dizzy.
The only reason I'm skepical of the dizzy is that I have tried to caps and rotors and the timing marks seem steady as can be. I was under the assumption that when they went bad you would see movement on the timing marks.

 

i have good luck with my HEI. improved performance and efficiency of the ignition pretty drastically. and they have the same parts as the GM HEI which is very helpful

 

Well I think it would be a downgrade for me.... Currently have a msd dizzy and a Mallory ignition box with a blaster 2 coil.

 

Just curious Herr but if my dizzy is bad but not jumping around with timing would that be the magnetic pickup??
Msd shows a ohm test for them so I will do that before I swap dizzies.
Maybe for once I will get lucky and have a cheap part to replace.

 

Tested my dizzy and well within msd specs..... Ohms and play

Swapped out the dizzy and box for a brand new hei and the problem was the same if not worse. Shot a nice fireball out the carb on accel among lots of spitting and sputtering.

Vac gauge reads steady with a 1-2 hg vibration only at idle. Rock steady at 18-24psi during cruise.

Wtf????????

 

I sure thought that would do it, maybe valve adjustment is off as someone stated earlier in the thread.

 

Well out of curiosity I checked intake manifold bolts and found one slightly loose. I went for a test run and was able to accelerate although it seems that when I hit 1/2 throttle it still spit and sputtered.

Maybe a lose bolt with a badly out of tune secondary was causing a huge issue.

So next question is with a probably secondary bog and backfire do I need to go bigger in squirter or smaller??

 

Also notable that from a slow creep a full throttle blast will all but stall the car.

 

it sounds like things are pretty out of control with your cars tune at this point.
usually a back fire out of a carb is from the motor being to lean at that moment.
a bog can be too much fuel or not enough timing.
it sounds like now the problem is with the secondaries. also if you had a vacuum leak at the intake gasket, you should replace it. the air passing the gasket can cut a channel in it. so while you have tightened it, it still may have a smaller leak. when you torque down the ford intake manifold it take at least 5 passes on the torque sequence before it will be properly seated.

 

also what you have done is richened up the carb to compensate for a vacuum leak then fixed or reduced the leak and need to back on the carb

 

Ok will plan in replacing the manifold gasket this weekend.
5 passes? I'm not that lucky it took 8-9 on the 351w lol.
And I'm ordering a 600 vac secondary quick fuel slayer carb today. Its a street car so I don't need the 650 dp anyways and I'm sick of messing with it lol.

 

Well I'm gonna say if it's idling 17-18 inches of vac or more at 600-650 RPM you don't have a vacuum leak... Even if there is a small leak, it would be like .5% of WOT throttle, never notice it... First sign of a small leak is the inability to idle engine normally, usually acceleration isn't effected...

I would make sure the valves aren't a little tight, under quick acceleration that can cause a pop and or stumble... You want no more than 1/2 to 3/4 turn preload, shim as necessary...

 

My idle rpm in park is around 900 and I was getting around 17-18 and I haven't really messed with idle air fuel to dial that in any more since I'm ditching it anyways but that is very nice to know.
I'm getting a trick flow valve spring kit in the mail on monday so after I install I will make sure I pay real close attention to how much preload I get when I bolt the roller rockers back down.

Thanks guys, will update soon.

 

Well I disconnected the secondaries and payed more attention to the vac gauge. At idle I was only getting around 10-12 but was getting 17-18 at light throttle cruise so maybe a vac leak?

With the secondaries disconnected it did the same thing. So for right now I'm leaning towards to tight of rockers.

 

So checked the rockers and they were a bit to tight or had to much preload rather. Shimmed them to spec. Still get the same stutter and backfire.
Buddy is coming over to lend me hisbcarb off of his 5.0 and I will try that.

Lost lol