Once again, I'm going to attempt at beating a dead horse with power valves this time as opposed to a bump stick. So here's my deal. I have a 350 small block, 462 Camel-Hump heads 1.94/150, Weiand WC4d Staggared 4x2 Intake, Four 94's and Zoomies for headers, TH350 Trans and 3.73 rear end ratio. My cam is a small solid with the following specs: @ .050: 219/229 Lift: .456/.479 LSA: 110/118 So nothing too crazy here. Just looking to have a lil' extra pep in my step. The engine will be used as a daily driver and I'm looking for respectable performance but not trying to break any records. I'm leaning toward running a straight linkage as opposed to a progressive. It's not written in stone, but it's what I'm leaning towards. So my question is, with my said setup...which power valves would be sufficient for this setup? I was thinking 2.5's in all four and running adjustable jets. Or maybe 3.5's would be better? I just need a quick and solid answer and I'll be on my way back into the shop to finish getting my truck together. Thanks in advance.
i know someone's gotta be running something similar...and not just have the setups on an engine stand to stare at all day in the garage, making lumpy cam noises with their mouths...
I dont have a chev, or a 4x2 but lots of flathead experience with holleys. I would probably go 2.5 to start and then see how it goes. Best way to tell is to get it in the car and drive it and hook up a vaccum gauge and see what reading you getting at idle, underload and cruise. then these figures will give you what you need to know.
Thanks guys. Appreciate the feedback. Flatdog - By your comment I'm guessing you mean that they leak or don't stay put once you set them...?
"Once again, I'm going to attempt at beating a dead horse with power valves this time as opposed to a bump stick. " I'm no expert. Does the above quote mean you plan on using carbs with power valves as oposed to carbs with metering rods activated by a linkage ?(like many Carters)? Thanks
Last time I made a new thread, I was asking some cam questions to clear up some possible misunderstandings I might of had. The whole beating the dead horse thing is because Cam questions along with Multi-Carb questions have been asked time and time again, but there's never a single solid answer because not everyone does everything in the same fashion. So overall, I just wanted a little light shed on my blueprints. Just so that I can reassure myself that I'm heading somewhat in the right direction.
Ok, so before I go and start setting all of this up...I have one last question. I've decided on running all four carbs on a straight linkage. So I'll rebuild and install 2.5 power valves. For the setup mentioned above, would the stock sized jets be adequate? Or since the four carbs will be functioning together, should I jet down just a pinch? If so, what would be a good approximation?
Two things to think about here, 1. Holley 94's came in various varieties, which I 'm sure you now know. BUT they didnt all have the same jet, the common ones I've seen are from 48-51. I would probably start with the 48 or even a bit lower. 2. with the straight linkage you will have all working at once, this you know. BUT you will have about equivalent to 600 ( give or take) cfm carb working all the time. Juice usage will be pretty big, and you might even get some bogging down from take off. Again , not ever having run a 4x2 let alone go near a chev, but know what flatheads can be like on a pretty much stock motor with 2x2. For instance , on my near stock motor with 2x2 I had to lower the power valves from 7 ( standard in the kit) to 4.5 ( remember stock motor so better vaccum than a cam'd motor) and I also took the stock jets from 49 down to 45 as it was fueling too much ended getting down to 42. I know this isnt a chev, but you can see where I had to play with the carbs to get it right. I feel you will suffer the same problems. if it was me, I would buy 2 sets of power valves 2.5 and 1.5 ( from memory you have a decent cam) and I would buy 3 sets of jets42, 44, 46 and then the stock ones you have. try the stock frist and pull plugs and see what its doing and work back until you get a nice chocolate plug. remember , these carbs are as basic as can be, one step up the ladder from standing there pooring fuel in directly. so their not difficult, but on a 4x2 you need to change one thing at a time and document what you do so you can back track if you need to. its going to be a lot of stuffing around, but you will get there in the end. also REMEMBER, one backfire and your power valves are toast.
I'll keep all that in consideration. I'm still semi up in the air on whether to go with a progressive or straight linkage. Progressive will work no matter what the circumstance but a straight linkage seems as if it will let the intake/carbs take advantage of the cam and use it to its fullest potential for being what it is.
I think 2.5 sounds too tight. You will need the enrichment when you open all 4 carbs and the 2.5 may be too slow. If it is the car will fall on its face when you stomp it, then probably backfire thru the carb and pick up again. You need to have it running, at operating temp, in the driveway, foot on the brake, car in drive and measure the vacuum. Then you can install the power valve just under that minimum amount of vacuum. I ran a 350 with a 292H, 507 lift, 110 lca, 244 @050 and I ran 4.5 power valves on two holley 450's
Yea, I get what you're saying. I'm just trying to get the best approximation as to what setup I'll initially need. I want to be within the ballpark of having a good setup and not way off.
i have the same set up on a 327, you cant run a progressive on a wc4d there is no common plentum you will run lean on one side of your engine. each carb feeds 2 cylinders. my set up is a 40 over small journal 327 with 882 heads 1.94 valves econo port, crane aluminum rollers, pop up pistons. 10:1 isky 280 cam and ronco mag. with the straight linkage the car runs great but if it werent for the 373 gears it would probally bon off the line
and also i dont have power valves anymore i had the inside machined to fit a small balbearing in its place so the vacume of the engine controls it up and down.
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