2x4s and parts

[Michael C Henry]

I have two Holley 4160 600 cfm carbrueators on a 427 with a Comp Cams solid lifters and 252° and .598 lift. I bought and installed new power valves 25-8.5g It loads up missfires and will not run when it gets warmed up. The warmer the worse it runs. I figure the pluge are fouled now .I probably missed the combination completely. What jets would you reccamend also what vacum level powervalve ? I'M REALY GETTING TIRED OF ALL THE SMALL STUFF.hAD TO BE TOWED HOME ON A STRAP.I've been reading about the BG Road Demons.Bg has a new valve that fits down in the center under the air cleaner stud that is adjustable and takes careof the problems of a lumpy cam( the one often fixed with drilling the throttle plates)If I could get a couple that would work with a dual four set up.Is it asking to have car that is ready to go and not layedup all the time waiting for the next new part or adjustment?

[G.R.]

Mike I fought my Holley 650 for months--probably spent close to $200 on jets, power valves, rebuild kits ,etal. Turned out the carb base was slightly warped-- replaced it with an Edlebrock and my little sb has never run better

[HighPlainsDrifter]

Michael,
You installed 8.5 power valves?
With a 252* cam you will only pull 8 or 9 inches of vacuum.
That isn't the correct power valves to use. They should be 3 points below your vacuum reading at idle. Try using 5.5 power valves. The # is when the power valve opens and dumps gobbs of fuel into your engine so if they open too soon you'll foul plugs and run like crap and won't be able to set jet sizes or air mixture unless you get them right first.
Good Luck,
Perry.

[Excaliber]

Ditto on the power valve number. Big cam? Get LOW on the PV number. I'd be worried 5.5 is to high! Measure your vacuum at idle, wouldn't be surprised if you had near zero or only 2 or 3 with a BIG cam. If so, even 5.5 will be to big. Try advancing your BASE timing to increase idle vacuum. BIG cams like lots of base timing. You still want to be careful not to pull TO MUCH mechanical total advance timing so you may have to adjust that. But base timing is critical to a "decent" idle speed with lumpy cam.

...wish I had a couple of 600 Holley with power valves. Mine are 660 full blown drag race RADICAL Holleys. I gave up trying to get a "decent" idle, it's just "OK". Hold on if you nail it though, it WILL launch!

[427 S/O]

Mike, their right!, I'm running 282-286 duration with 597-609 lift and 7 inches of vac., I used 3.5 power valves and 18 degrees advance @ idle when I had the 600 holleys. Ran great...

[427 S/O]

Excaliber, I have two 600's that I will probably never use again since I bolted on the in-lines, I upgraded with non-stick gaskets, vent whistles, quick change spring kit plus extra springs, they have about 6000 miles, I will install jets and power valves to match your vacuum and engine particulars if your interested.

[Excaliber]

I am interested! Heres the BIG QUESTION! Will those bad boys flood on a turn or when you stop to fast? THATS what kills me with the 660's, they only want to go straight!

I'm thinking 66 jets and 3.5 PV. Lets make a deal.

[Michael C Henry]

When I bought it in Reno in 99 and brought it to Washington (near sealevel) .It was diagnosed (by emmissions) as having a lean missfire. Several of the shops I talked to talked about drilling the throttle plates to get it better. It had # 64 jets in the primaries.I was told that #67s came standard from factory.I added a plate in the secondaries from Quick fuel Tecknowledges that would accomadate regular changeable jets and a notched float.In the primaries I moved up to #68s. Since, the floats have been adjusted up and down.air bleeds have pluged and cleared,choke towers were milled off,float whistles .large needle and seat. I have two Carter 15 psi 100 gph pumps and a new Bg adjustable fuel log . I started out at 6 psi on one pump and 7 psi on two .I have since lowered pressure to 3.5psi at the fuel log.The rest of the fuel is returned to the tank constantly.It has been down for over two years and I want it to result in a dependable car that isn't allways waiting for parts.Getting towed home isn't desirable.I have to get it running close to right in order to get it perfect HA HA .

[G.R.]

427s/o can tell you for sure on his--but generally if they have been converted to center float bowls with the upgrade kit, you won't experience the flooding problems you have with the 660. I'm no Holley expert by a long shot but I did get a real learning experience with the pos one I had.

[Excaliber]

I checked out the price of a conversion kit to change over to center floats! WOW, thats BIG money, I forget now how much but it was enough that I stopped seriously considering it for my 660's. I think they have more problems than "just" the floats.

How much was it? It was SO much I could buy a new Edelbrock carb!

[G.R.]

lol-I know I spent almost enough on parts and pieces that I could've darn near bought a new carb before I wised up and did

[Michael C Henry]

How do you get 2 4s inline with center pivot floats?

[Excaliber]

You know, I don't think you can now that you mention it. Two NORMAL Holleys barely fit.

[427 S/O]

The vent whistles stopped the flooding on quick stops, never had a problem in turns.

[Michael C Henry]

Quick Fuel Techknology said that I want to check the vacum at idel in gear.and go 1.5 below that. As I understand it when you open the throttle you get the initial squirt of gas from the accelerater pump and the vacum drops, the power valve opens and delivers anm additional supply of gas ( in addition to the fuel being delivered through the boosters via metered jets) untill the engine catches up and is running closer to effeicient.the vacum builds and power valve closes and the engine continues to run on the fuel controlled by the jets alone.
I missunderstood and bought a pair of 8.5s a while back.When I had all the gas running in because of the plugged air bleeds and all the backfiring .I changed the powervalves It wasn't drulling but it started backfiring more and got worse as it went untill I quit.Plugs were all black.I'm starting with the 3.5 this time.The lower I go the sooner the valves close.Too early and I loose power.I have to get it running to get a reading and start to tune .

[427 S/O]

Exactly, then you can work up from 3.5 if necessary.

[Steve R]

Mike,
I have 2 holleys. My main jets are .060 and my power valves are 3.5. The throttle plates in my carbs have a hole drilled in each one to let a little air in for idle. If you want, I will get the exact size of the holes. The setup works unbelivably well. The cam is just over .600 lift. I can idle and put around town all day, or show you my tail lights at a moments notice
Steve

[Steve R]

Mike,
You must drill holes in the throttle plates in order to have them in the proper postion for idle. If you don't, you will be inclined to adjust the throttle fly screw to open them enough to get it to idle. The problem is, that the throttle plates are now exposing the transition slots. This makes for a $hitty rich idle.

Have your carbs been drilled yet???

Steve

[427 S/O]

Use a 3/32 drill bit and drill on the opposite side of the transition slot and center the hole, as steve says, it works.

[Michael C Henry]

I installed the pair of 3.5 powervalves.Vacum was measured at 5 to 6 and idle at 650 rpm .Checked timing .Oh crap! it's about 4° after.Tried to turn distrib got to about 2° bftdc and distributor housing (tach drive ) is hitting the manifold.Pulled distrib tried to move one tooth and then reingage the oil pump, installed the hold down. I crank the engine .Man does it take off.Get out and point the timing lite 36° bftdc .crank back idle adjustment screws.Get it to a reasonable idle.I turned the distributor counter clockwise as far as possible ( hold down nut is difficult to get to now. burried under the tach drive. timing is set at 12° and advances to 32°,vacum is almost 8g and run on has stopped.It is sharp. Mallory HyFire VI has a programable start retard .I've programed 8°. I hate to mess with it But you think I may have jumped two teeth when I lifted the distributor? Don't remember the hold down ever being buried under ( so close that have to use a open wrench under the tach drive)