I bought a 8007 holley 390cfm carb off this old man who swore he made great mileage with it. I had my carb guy do it and we put it on my motor. My slant a 436 lift MP purple Shaft, 8.2: 1 CR, 3.23 Gears, A904. On the carb we started off with 48 jets but it was acting to lean, so we went to a #52 and it still wouldnt hold idle, I currently have #63 Jets, 6.5 Power Valve, anti blow out kit, and Yellow secondary spring. I kept the stock 25/30 cc accel. pump and I took it out for a ride, there is a dead spot in the car between 2700rpm and 3100 rpm, I drove it at night on the freeway and romped on it, she was fine til 2500rpm then she started acting like the accel pump is too tight (she was going then hesitating repeatedly, sounded like cylinder popping very fast) and she continued this until i dropped into 2nd gear and she cleaned right out, its very odd, does anyone have any ideas or has anyone encountered this with the 8007. Thanks

Pyper70@aol.com

How about lock the secondaries so, that they will not open at all. A simply test, and after it you know which side of the carb is causing the problems. No need to change harder springs, only locking it with piece of steel wire or something. Dont build anything that could get the carb stuck at WOT!

One possible reason is when the secondaries start to open they will not start to deliver fuel (secondary side fuel level low?) and the engine goes terrible lean.

If #48s are stock jets, and you have to go up to #63s there is something mystery at the primary side, too.

JKKo

'66 Dart with Carter BBD


jari@kuparikuviot.fi

Sounds like either a secondary "main feed" lean-out ot the power valve is set to low for the enrichment needs of your engine.

I would "tie-shut" the secondaries and then "dial-in" the primary side using a Vacuum gauge to set the power valve. Once this is done , untie the sencondaries and work on the "kick-in" timming and mixture / distribution.
What is you current manifold vacuum reading at idle? My bet is that it is pretty high with that cam so my guess is that you need a 8.5 to 12.5 power valve.
DD

The stock primary jets in this carb are 51's. My engine is happy with 55's. I also found that the stock (looks red but could be orange)accel pump cam in the #2 position works well. I still have a very very slight hesitation when getting into the gas that I planned to try a higher# power valve to fix but it's so slight I just have not taken the time to pull the carb to make the swap. The yellow spring is a little to light but I like the kick sensation when the secondaries open so I leave it alone .

My Hot-Rod 6
dave.clement@motorola.com

At idle I have 16" of vacuum in gear its about 13"

Pyper70@aol.com

I'm running #58's on all four corners in mine. Mine has been converted to a jet style block in the secondary. I have a #65 power valve in, a long yellow spring in the secondary pancake, and the stock pump cam. #63's sound pretty rich for a mild motor.


slantzilla@excite.com

What size cam are you running, I got it from the guy with an orange cam and I now have the blue cam in it, What would be your guys' input on that. How did you do the Jets in the secondary metering block, is there another carb I can steal it off of? If I put a bigger Power valve in, say a 10.5, can I put smaller jets in the primaries. I am seeing there really is no difference between 2bbl 500 and this 4bbl 390, given all the bugs arent worked out but i'll be happy if I get 15mpg. Thanks guys.

70 Swinger Super Slant
70 Charger R/T
69 Charger R/T



Pyper70@aol.com

The stock accelerator pump cam is red (could be orange but looks more red to me). Anyway I use the #2 mounting postion which is a more agressive squirt initially.

This carb is a 4160 series and uses metering plates in the secondaries. These can be swapped for differnt sizes but you do not have the flexability with bleeds and jets you would have with a 4150 series carb that has metering block and uses standard jets. Holley sells a kit to convert and it's available from Summit, Jegs, etc. for about $40.00.

There are different ways to select the power valve but the most common I have read is take your steady state crusing vacuum and divide by 2 and get the one closest to that figure. If you go to a higher vacuum number power valve it definately can impact the primary jet size.

FWIW, My 225 has 0.060" shaved from the head, has a Comp Cam 252S cam, the 390 on an Offy, 6 into 2 headers, dual exhaust and runs through an OD 4spd with 3.23 gears. I get 20-22mpg in my 50/50 suburban-hi-way commute.

Hot-Rod 6
dave.clement@motorola.com