do not hook up the vac advance. It could be pinging because it's advancing up to 50*

Have you ruled out vacuum leaks?

Im going to run some sea foam through later and check it again. When I bought the car, it had an older 1413 800 on it and didn't run good. The guy thought it did...lol. This one looks pretty old. The motor was bought in 2007, so who knows what has happened changing a few hands before I bought it. Plus from year One, it was tested with a Holley 850. I was excited to buy a 68 RR for a good price. Didn't pay attention to these issues. Normally I could dial them in pretty good. Im getting a leak down test set this afternoon as well. So can better diagnose it hopefully for tomorrow's post. If it's heads/valves I would be happy. Wet shows no change so it would appear rings are good. Pretty low comp with 130-140. So I assume 9:1. But seeing what the other details that were not tended to, I think when they installed it, they had no clue what was happening and could have very well ran it lean or pig rich for a long time. Either could have carboned it up pretty good??

Springs now are silver. Wanted to get as much fuel as I could. As you can see, it's getting better based on the 2nd plug pic I posted. Vacuum fairly consistent at 10-12. But a bit shaky on the needle. Plus I think I had reg fuel. Changing that today as well with some 91. It seems it wants lots of fuel to run the AFR near normal. So 70/37 rods with .113 jets are all I could find in my shop right now. Plugs are getting fuel better then the first plug pic post. I could get the 1490 kit and still play with the 800, as the 750 has too much play in the throttle plate rod as I found out last night as well. Good vacuum leak there and seems to be binding.

We got a crate 440 for my sons 72 Charger and put on a Holley 670 avenger. Runs nice...a bit rich but nice. So don't get it.

Well shouldn't it be running at 50-52 all in? But I'll try it.

yuup...tried all areas. Is manual brakes, so no poster to worry about. Plus im getting 10-12 hg vacuum, so that's pretty normal. But spec sheet form year One said 14 at 800 rpm. But that could what they all said without checking the actual motor....lol

Im going to do that. This one makes sense as that would give a AFR of 23 but small rich for sure.....thanks. The leak down tester will also do the same so that's next.

Sorry guys...I've always read the posts for info never posted..lol. I have to learn to hit "quote" when I reply

I have a relative stock 440 with a mild XE262 Comp Cam, 915 heads, all cylinders at 160 and one down to 125 and it still pulls 20 hg vacuum. 10-12 with a bouncy needle seems telling, as do the relative low compression readings. Hopefully the leakdown reveals something easy. Unfortunately mine did not!
Silver spring would get you the most gas early.. Maybe the .065 x .037 jet would do? Solve compression issue first.

Yuup. Did sea foam and changed fuel to premium. Most pinging gone...haha. Now I'll do that leak down and see. Wont be until tomorrow as kit never came in on time.
But think I may go to Quick Fuel carb anyway. Eddy seems to not like my motor. But first compression issue.

Don't know cam manufacturer just specs.

OK...latest....this 1411 is pooched. The throttle plate shaft is so loose that there is a diff of 4 hg vacuum. And it binds a bit so wont seat back to idle properly. That's my vacuum leak....

The 800 I have is a bit older and im afraid to play with it anymore. Plus it cam with the car and it was backfiring when I got it home. I need a 1480 strip kit to play with it. So save the $60 toward a new carb is the plan I think. I put a carb kit in it, but still runs poorly. Maybe it's me with carb kits and I don't know what im doing....

So chime in guys....looking at the QFT Slayer 750. I think 750 is enough. Could go 800 AVS Edel and jet down if needed. But this time I think a change wont hurt. Plus get a review for the forum....lol.

thoughts

do you still have the old carter 625? If it were me I'd pick up a Holley 750DP or HP. But that's me.

Yuup I do, but it's real old. I would think it's too lean according to my AFR readings. But I could try it.

This 750 was new on the crate motor I bought for the 72 Charger 3 years ago. We had issues right when we started that one up. So bought a 670 Avenger, and ran nice. It's a 475 HP build and higher compression. So I should have clued in putting it on my 440. Tis why I was thinking the QFT 750. Can jet down after if needed. But hard to go up. And that's what I was thinking????

Well bad news. #1 has 12% leakage. At 90psi the Gauge reads 79 psi. So guess I know why I'm at 115 comp now. So a ring job. Hopefully walls are ok...since I have to do all this, may as well change out the Pistons to KB? Damn....didnt need this right now....would drive as is in sundays..lol. Until fall then yank her...lol

Is 12% really that bad? Considering the constant air pressure is bleeding past piston rings and maybe valves, is not how the engine actually operates, I think you real loss number is less than that when combustion is measured in tenths and hundredths of a second?

What were your other cylinder leakdown numbers?

Well only checked the bad one. Guess I should. But an update is its not the rings. I just have had it off a bit from TDC. The sure is actually coming out the exhaust. Hear it like a tire leak...lol. This 440 has the oil filler on top #1&2 so you hear the air passing by making it sound like the crankcase. But it got worse after I did a wet test again. Now it's reading 45psi with 90psi feeding. So that exhaust valve has to be deal with. Makes more sense now with my carb sir problems I would say?

Darn phone auto correction. Meant to say AFR readings.

i agree, 12% is not that bad. i think i remember an engineer buddy telling me 9% is still ok for a street engine. i certainly wouldn't tear an engine down for that, not unless you are going after every ounce of power.

i'd leave it, your issues are elsewhere...

slightly different kettle of fish, but i had a 4 cylinder engine with 35% on one cylinder. it ran better than my current one. exact same engine, haven't done a leak down on the current one, but i doubt any of the cylinders are that bad.

get rid of your carb issues, drive it and have fun!

Supercuda...I owe you an apology. Wow...do I feel stupid. I finally welded in a bung. Being in the high side of the 750 even having that throttle shift issue, I'm at 12.5 at idle. A 15:1 diff from tailpipe. And innovate said it's fine? So accept my apology....

I did buy the QFT slayer 750 anyway. So I'll play with this eddy 750 for the experience, but think I'll change it.

So now to deal with my valve issue according to the leakdown and finally get this on the road.

I appreciate it, just trying to help. Benn following along. Hope you get it sorted out, BTW, the jets and rods from your Edelbrock will work in a Carter too. You might have to swap rod covers if they are different though.

And I appreciate it..Well I've got this 1411 jetted down a bit and now my AFR is correct, I have to go down more. So I'm worried that the QFT 750 might be too much.ill take it for a spin and see what the other readings are then tweak some more.
Thanks...mike