Wen I converted 390 from a 4160 single feed with metering plate to a duel feed 4150 duel feed with secondary metering block with jets. The only jets I had on hand were 64's not this has to be way to rich, what would you all suggest going down too? I am also going to lighten the secondary spring because I do not think that the secondaries are opening..

What size jets are in the primary?

I would install a wide band O2 reader to get your A/F ratios just right.

MBHD

I plan on investing in one. You always bring it up( not complaining, I know it is the right thing to use), and I have read about using one. I think I will invest in one. I have 54 in the primary's, right now, I am picking up a parts carb Sunday that may allow me to steal the main jets out of my 570 Avenger (55's) that would allow me to use those in the secondaries. How much and where would a guy get a wide band O2 sensor?

Sorry, forgot I had told you before about an O2 reader.
55's should be in the ball part I would think. Just have to try it.

I am partial to Innovate, but others work OK also.

http://www.innovatemotorsports.com/products/MTS.php

http://www.ebay.com/itm/Innovate-NEW-384...870&vxp=mtr

http://www.ebay.com/itm/Innovate-LC2-Wid...ce7&vxp=mtr

http://www.ebay.com/itm/APSX-D2-Digital-...162&vxp=mtr

MBHD

You preach them, for a good reason, they are very important. I do want one especially with my 65 V8 car. It has The 290hp/350, 222* cam on 114 LSA and 8ish:1 compression, bad comonation, good duration but way to wide of a LSA for a low compression crappy headed motor! ( I see new cam on 110LSA in the future). When I put the carb back on the 250 I will drop the jets to 55 or so and go from there.

Sounds like a turbo grind cam.
Just for now, advance that cam 6 degrees or so to wake it up.


MBHD

IF I get that deep inside I am going to go for a grind like this
http://www.summitracing.com/parts/cca-12-319-4/overview/make/chevrolet. Hoping it can wait till paint so the front end will be a part, so I will not haave to do it twice

That cam would be OK if it had more compression.
With your engine having only 8.0:1 compression ratio, I would look for something in the 200-210 degrees duration @ .050"

What is the cranking compression right now?

MBHD

8.0.1 compression is as low as a brand new 292 had off the line...now throw a turbo on that thing and you'll be fine. lol But you'd want at least 9.5.1 for that combination.

I have not dug that deep. just got the car and it was in there, brand new too! The cam is the same as I have but tighter LSA and .015 and.005 more lift. Crappy cam for a low comp. engine. I thikg Summit Iron heads and a trip to the machine shop to get it to the 9.5 that cam needs!

The cam that is in there now
http://www.summitracing.com/parts/nal-3896962
I am going to change the plugs and check all that stuff then.