Help! Jet 850 down vs jet 670 up vs buy 750

[cudablue]

Hello gang,
This is kind of a spinoff from my other thread. "sputtering issue with new carb".

Holley 870 vac,: I jetted down to 78 primary/82 secondary from 82/82. Sputtering was better, but still did some.
Can I jet down further? How do I know if it's too lean?

Holley 670 vac: I jetted up to 70/71 from 63/64. Ran great. No sputtering. Engine ran a little warmer. I don't think outside temp was much warmer. I'm worried it was running lean. Again, how do I knw it's lean?
I'm not experienced enough to tell if it lean. The plugs were spotless. I'm paranoid about running it too lean and cooking my new motor. Can I jet it further?

Edel 750 factory jets. It ran good. It seemed to load up a little at start, but fine after that. Performance seemed less than both the Holleys. The plugs were spotless and does not appear to be rich.

Buy a new Holley 750? Or Edel?

I'm friggin tired and in the dog house buying carbs. I am ready to buy one more and sell the others if need be.
Help!!!

Specs:
Vacuum at idle is 10 to 13. Not sure what it is at higher rpms.
Intake is Edlebrock performer dual plane (spreadbore) has 1" adapter plate to square bore.
Mallory electonic distributor.
360 block with 318 heads. computer specs with this build shows 450 peak HP (5000 RPM), 540 peak torgue(4000).
Lunadi hyd cam 30405 , Duration (.50) 224/234 , lift .318/.338
Bored .30 KB 107 pistons. High polished cylinders.
New Carter mechanical fuel pump 120 gph. 3/8" to carb. 6 psi.
5/16th line from tank to pump. 3/8 from pump to carb.
160 degree t-stat.
Headers
3" stainless magnaflow.
4 speed / 3.23 SG.

Hopefully this gives enough info.
thanks!

 

[Chryco Psycho]

Jetting is best coorected with an O2 meter 670 upjetted will not be lean , the carb is set to allow a certain amount of air & proportionate amount of fuel , the plugs should be light tan after a cruise on the highway 5-10 miles but may not read right with eathanol fuels

 

[C O D Y]

Cam is the biggest thing when you want to make your engine run smooth and easy. I've learned the hard way. I went through the same thing and fought 3 carbs until I switched to a Mr. Six Pack cam and now the motor is like brand new and runs and drives like a champ. I HATED my motor until I made the cam change, now I love it and it runs better than a new car. To many people put to aggressive cams in street motors. Not sure about all the specs on your cam, but might want to think about looking at the cam instead of a 4th carb.

 

[cudablue]

Thanks for the input guys!

 

[Chryco Psycho]

I bet I could help you get it tuned properly but I am a long distance away

 

[moparleo]

I think Chryco Psyco's point is you need to go to someone who knows how to tune a car. Not just throw parts at it. I would find out who in your area has the best reputation for performance tuning a car. Other wise you will only get more confused.

 

[BIGSHCLUNK]

I'd say buy chryco a plane ticket! Then you know you got it handled.

 

[DukeBoy]

Remember, with ethanol fuel, it is already running a certain amount lean to begin with. This isn't as big a deal when it's Fuel injected, but carbs can be finicky at best when alcohol is a factor.

 

[moparleo]

Small port 318 heads on a 360 ? Big restriction on the build.