440 issue after swapping to aluminum heads, need advice

[ykf7b0]

I had terrible luck with timing tape...No matter how clean I get the balancer, it never stuck. A "Dial back" timing light is a huge leap over a standard one.

I removed my balancer and after a good cleaning I stuck the timing tape on then I clear coated it many times with the bomb can. Mine has been on now for close to 10 years.

 

[4speed68rt]

The old standard question: What kind of gas are you using? The Edelbrock heads probably increased the Compression ratio, making it detonate worse. Many discussions on this site about that. Carburetors aren't perfect.
Advice: make sure you have good, high octane gas. Just my opinion.

 

[ykf7b0]

I believe a person can get away with a point more compression with aluminum heads.

 

[66Satellite47]

So you had detonation before installing the Source heads. They are not the problem, if anything that should have helped some. That oddball intake sure looks like a possible cause.

 

[66Satellite47]

The old standard question: What kind of gas are you using? The Edelbrock heads probably increased the Compression ratio, making it detonate worse. Many discussions on this site about that. Carburetors aren't perfect.
Advice: make sure you have good, high octane gas. Just my opinion.

The OP said they are 440 Source not EDE. The Source heads have the large chamber far as I know. Good gas sure does make a difference.

 

[Lefty71]

Are you still licking windows on the public bus?

 

[Cheapsunglasses]

I would dump that intake real quick. It is a POS.

what cam do you have in there?

Sorry I didn’t make that clear, it’s a stock low performance

I would dump that intake real quick. It is a POS.
4966 is one of the leanest carbs out there.

what cam do you have in there?

So I should give up on that carb?

 

[WileE]

I only lick the ones that are not self stick....
Are you still licking windows on the public bus?

View attachment 1297022

Here's a reminder for ya !

 

[Cheapsunglasses]

I don’t mean this to be rude, I greatly appreciate everyone’s input, suggestions, and kerndog and friends peanut gallery. But I don’t think my question is being answered, and maybe I’m not asking right, because I have no idea what I’m doing lol. I’ve worked on stuff before, but I’ve been lucky enough bolting stuff together worked fine. I bought this car as barely a roller 5 years ago, and slowly been building it as cheaply and good as I can. A lot of my parts were bought before I had a mortgage and responsibilities lol, and before child sniffer and his regime took over. Moneys tight and if possible I’d like to make what I have work

My engine before the head swap, other then the detonation, ran pretty good with the intake and avs carb, maybe a little lean. I put heads with potential to flow better, but same intake, carb, and cam, it’s my understanding it can’t, because it’s really the cams job to pump air, everything else just feeds it, I could be wrong there too.

So why all of a sudden the avs has no tune ability, and has no in between, and won’t go past 3k

But an edelbrock 1406 which might be too small, and an afb for a 440, without tuning does a nice lean to rich as rpm increases, which I think it’s suppose to do but IDK, but still won’t go past 3k

When it’s too lean, it has no trouble getting past that 3k though

 

[ykf7b0]

Another area to double check is vacuum leaks.

 

[Cheapsunglasses]

Another area to double check is vacuum leaks.

I’m sorry if I haven’t mentioned this, I’ve sprayed brake cleaner around the carb, There is no sign of a vacuum leak

 

[Lefty71]

I’ve sprayed brake cleaner around the carb, There is no sign of a vacuum leak

Vacuum leak can occur at the manifold to head joint, and can be especially troublesome if underneath, because very hard to find. I had this happen on a 400 once....and i believe it was a dowel locating problem.... So, in that case, we cut the manifold to fit and it fixed the problem. But it was'nt a consistent leak front to back and top to bottom. Is there any possibility the manifold you are using has already been cut?? You need to be real careful if you haven't owned it since new. Did you physically check the fit of the manifold against the heads before any intake gaskets to see where it lays?? I actually scored that 400 for cheap because the previous owner was sure his issue was bad AVS carbs and he was'nt rebuilding them correctly. It was hunting like mad and it would not rev, just lean out.

HTH, Lefty71

 

[diesel_lv]

Where do you have the O2 sensor mounted? Must have at least 2 feet of pipe after the sensor otherwise you'll get lean readings.

 

[Cheapsunglasses]

Where do you have the O2 sensor mounted? Must have at least 2 feet of pipe after the sensor otherwise you'll get lean readings.

The best place I could get to was just before the transmission crossmember. I had an o2 sensor in another vehicle for carb tuning, and it was about the same place, and that vehicle runs absolutely perfect, so I don’t think o2 position is a problem

 

[Cheapsunglasses]

Vacuum leak can occur at the manifold to head joint, and can be especially troublesome if underneath, because very hard to find. I had this happen on a 400 once....and i believe it was a dowel locating problem.... So, in that case, we cut the manifold to fit and it fixed the problem. But it was'nt a consistent leak front to back and top to bottom. Is there any possibility the manifold you are using has already been cut?? You need to be real careful if you haven't owned it since new. Did you physically check the fit of the manifold against the heads before any intake gaskets to see where it lays?? I actually scored that 400 for cheap because the previous owner was sure his issue was bad AVS carbs and he was'nt rebuilding them correctly. It was hunting like mad and it would not rev, just lean out.

HTH, Lefty71

I’ve sprayed brake cleaner all around the intake as well and I don’t appear to have a vacuum leak.

 

[Lefty71]

My engine before the head swap, other then the detonation, ran pretty good with the intake and avs carb, maybe a little lean. I put heads with potential to flow better, but same intake, carb, and cam, it’s my understanding it can’t, because it’s really the cams job to pump air, everything else just feeds it, I could be wrong there too.

Sorry I missed this before.... So you really put the same parts back together, just with different heads.... It ran good before... I think that really leaves out, that manifold is sh*tty, or the carbs too lean, bad gas, etc. Do you know for a fact that a machinist never cut the old heads, the new heads, or the intake manifold??? Also, how closely did you look at the fitment of those items, coming apart, and going together?? What is the intake seal?? Bathtub type gasket only? or with gaskets added? and any sealer used on the intake?? And all this just recently done, or slow progress over time?

 

[Cheapsunglasses]

Sorry I missed this before.... So you really put the same parts back together, just with different heads.... It ran good before... I think that really leaves out, that manifold is sh*tty, or the carbs too lean, bad gas, etc. Do you know for a fact that a machinist never cut the old heads, the new heads, or the intake manifold??? Also, how closely did you look at the fitment of those items, coming apart, and going together?? What is the intake seal?? Bathtub type gasket only? or with gaskets added? and any sealer used on the intake?? And all this just recently done, or slow progress over time?

I changed the heads a month ago, I’ve been fighting this issue for a while, I checked fitment before installing, I’m using bathtub gasket with gray rtv, all my bolts are tight. 1 carb might be junk, 2 carbs run good, but start cutting out, that sounds ignition like. When it cools down a bit outside, June in Texas what do you expect, I’ll start looking into ignition. If that doesn’t fix it, well I guess I’ll start changing things. Thanks!

With y’all’s help and a little more thinking I might have come up with a solution, again I want to thank everybody’s help!

 

[Cheapsunglasses]

I know idle you want 14:1 or so, but I’m curious on what my target AFR is after idle

 

[WileE]

I don’t mean this to be rude, I greatly appreciate everyone’s input, suggestions, and kerndog and friends peanut gallery.

Hey, never forget this from over 50 years experience... if you can't have fun, while you're having fun, why bother ? Sometimes a little levity takes the edge off. If you've never got pranked, well...

 

[WileE]

This ones for you !