Holley 770 question

[mopar head]

Im downsizeing a powervalve, street avenger, where the heck is the powervalve located? under acellerator pump or do I need to pull fuel bowl? primary or secondary? I cant find a blown view anywhere. thanks:read2:

 

[rumblefish360]

Try Holley.com fro a explode veiw.

The power valve is in the bowl, er, behind it.

Take off the bowl and see it.

 

[kocuda]

The power valve should be in the secondary metering block if memory serves me.

 

[mopar head]

Try Holley.com fro a explode veiw.

The power valve is in the bowl, er, behind it.

Take off the bowl and see it.

primary bowl right? also I have new bowl gaskets for 750 dbl pump, will these work on the avengers? when I ordered it I was assumeing it was under accel. pump. dummy me

 

[mopar head]

The power valve should be in the secondary metering block if memory serves me.

what little I read I was thinking secondary bowl too? help. lol

 

[rumblefish360]

Holley.com or just open it up!

 

[mopar head]

their site just gives you instruction sheets which does`nt have blown view, which sheets I saved and have. and stop yelling at me I got feelings ya know:-D thanks fellas

 

[rumblefish360]

Aint yellin, just sayin, open it up and look. Don't be afraid!

 

[green1]

Front metering plate.

 

[mopar head]

he he, well I was afraid...... of screwing up gaskets, unnessarily. Took off secondary bowl, no valve, but saved gasket, same with pump. it`s behind primary, saved block gasket, but bowl gasket tore to heck. the 750 gaskets are the same, so, good to go. I`ll test drive tomorrow, see if it helped. tryen to lean her out a little @ wot.8)

 

[rumblefish360]

Use the blue gaskets when you reassemble it.

 

[green1]

get the blue gaskets, re-usable.

 

[Babyblue66]

he he, well I was afraid...... of screwing up gaskets, unnessarily. Took off secondary bowl, no valve, but saved gasket, same with pump. it`s behind primary, saved block gasket, but bowl gasket tore to heck. the 750 gaskets are the same, so, good to go. I`ll test drive tomorrow, see if it helped. tryen to lean her out a little @ wot.8)

Changing the power valve will not lean it at wot. You need to change the jets or rear metering plate/jets to lean it out.

The power valve number determines its opening point. At the vacuum level of 6.5 inch, the 6.5 P V will start to open. At wot there is no measurable vacuum. Thus any power valve will be open at wot.

 

[mopar head]

Changing the power valve will not lean it at wot. You need to change the jets or rear metering plate/jets to lean it out.

The power valve number determines its opening point. At the vacuum level of 6.5 inch, the 6.5 P V will start to open. At wot there is no measurable vacuum. Thus any power valve will be open at wot.

So true. Just something that needed to be part of my tuneing attempt, 12" vacume@ idle, put in 5.5, it seemed to improve cruise to accelerate better? Since I got a few of you guys attention, maybe you can help me out. I`m trying to lean out a ritch idle, plugs seem ok@ cruise and a hard run. but recently I wound it out a little @ night and could see a pretty good fume trail in the dissapearing headlights behind me, cant tell in daylight. I`ve experamented with the heaver secondary spring, seemed to lost some quickness via butt dyno, so I replaced the factory silver spring. As far as idle I`ve adjust needle valves to where the engine ran its highest rpm then brought it back down with curb screw. = pretty ritch. should I lean it with needles and crank up the curb? out of box specs, as follows- primary jets=72 sec. = 75, .025 discharge nozzle, 65 powervalve/ allready replaced with 5.5. Plugs to me look decent with exception of fuel/and or oil blowby. Engine is 69 340 x heads, .030, over rebuild. tti headers, MP ign. conversion. eddy rpm airgap. 770 street avg., 323 8-3/4sg. I`ll post cam card and plug pic. any tuneing tips/tricks will be much appreciated8)

 

[mopar head]

Any holley guru`s want to suggest jet sizes, etc, etc. I would like to get it right for once, without ten removals8)

 

[ramcharger]

How timing are you running? I need both initial and total without vacuum advance. Also, what displacement engine are you running?

 

[mopar head]

How timing are you running? I need both initial and total without vacuum advance. Also, what displacement engine are you running?

about 12- 34 seems to run its best. Advance plugged. 340 as posted earlier. I did have a total mopar nut from NC,take a ride, said it sounds like I have lazy timeing? you thinking timeing? thanks:clock: I`ve never had it recurved, will need proper procedure on that if I do.

 

[mopar head]

Days go by and thread goes to the great library in cyberspace:clock: Thats ok ramcharger, anyhow, Whats great about this site is people get me thinking and learning to help myself. I acumulated enough knowlage from this site to gather up the confidence to try and performance tune my 340. I always thought it run pretty good but suspected it had more in it. Ramchargers response made me remember what I read here, TIMEING FIRST! now with that sunk into my thick skull, I decided to tackle distrubiter recurve:read2: Mopar Performance electronic conversion, makes this simple with there adjustable stop plate, great design feature. My 340 wanted 18-20 degrees advance! OMG!! what a difference in off idle torque! It`s hard to let the clutch out without a little spin, launches like a rocket, and even chirpin gears:cheers:. The tailpipes are even starting to lighten up in color. I`ve been running this poor bastard for a many years stinkin ritch, its a wonder I have`nt hurt it. The vacume went up so high @ idle, I had to put the original powervalve back in. NOW, I can go to the carb and wring the rest out of it. I brought it up to 6 grand and heard no detonation, heck I might try 6500 and see how she does? Carb is still ritch@ idle, gonna get the nerve up to do the drill holes in the throttle plate trick soon. Not enough road time to do any plug reading yet but hopefully I can get this baby dialed in. When I built this car I had absolutly no one to turn to, no computer, just a subscription to mopar muscle mag. Thank goodness for FABO!!!!

 

[ramcharger]

Oh man, sorry about that. I've truly been busy as heck lately. Glad to hear that you have it worked out and that a "hint" was all you needed to figure it out.