Cascade Crew

91RSVert · Posted: Mon Dec 31, 2012 10:27 am Post subject:

is this the right kit?

http://www.summitracing.com/parts/hly-20-12/overview/

chevymad · Posted: Mon Dec 31, 2012 10:52 am Post subject:

Pump shot isnt going to change the look of the plugs, only get rid of hesitation at tip in.

That kit will give you all the different cams.

You're main jetting is leaner then the factory setting. That will change the look of the plugs. I gave you factory settings above. If anything you may even have to go richer then that. You can buy new jets or if you have any smaller ones from other holleys you can redrill them larger.

Oh and 0.040 is fine. HEI will work with anything between 0.035 and 0.080. But the wider you set it the harder it is on plugs and wires and the more chance you take for a misfire. Usually 0.040 to 0.045 is a good place to be.

izcain · Posted: Mon Dec 31, 2012 10:57 am Post subject:

91RSVert · Posted: Mon Dec 31, 2012 12:57 pm Post subject:

If I go to switch my jets from primary/secondary, I need the bowl gasket, and that other one to the main body correct?

Also, what are my thread sizes? 1/4-32, 5/16-32, 6/32??

chevymad · Posted: Mon Dec 31, 2012 1:17 pm Post subject:

You'll still need secondary jets then because those are correct. If you used the blue gaskets they should be reuseable. No idea on the other.

aaron_sK · Posted: Mon Dec 31, 2012 1:22 pm Post subject:

Brown or black paper gaskets are crap. Get blue and reuse them.

If you're pulling it apart I would still suggest plugging the secondary PV and upping those jets, but you may want to try one change at a time.

chevymad · Posted: Mon Dec 31, 2012 1:39 pm Post subject:

Getting rid of the secondary powervalve just simplifies things. But that also will mean the fuel curve won't be quite as exact. Right now the 2nd powervalve is adding a bit more fuel before the secondaries are really kicking in. So if he runs at say 1/2 or 3/4 throttle alot he should get better mileage with the extra power valve. Secondary side is very close to stock setting right now. I'd leave it alone at this point. If he does choose to ditch it then he'll need to measure the ports in the metering block behind it. That spreadbore holley is adding alot more fuel via the powervalve circuit, with the jetting they report, then a square bore does.

Wish he had an old junk 1850 to steal some jets out of. Then he could progressively drill them to different jet sizes to find the best. He could do that to his current ones, but once he goes too far he has nothing to put back in.

91RSVert · Posted: Mon Dec 31, 2012 4:33 pm Post subject:

I figure this thing will get ran at 1/2 throttle most of the time for around town driving.

Blue gaskets are what I have now. I refuse to reuse any gasket other then rubber valve cover gaskets.

So what size threads do I have, and what size(s) should I order if I should leave the rears alone?

What I dont understand is this all ran before. Why is not correct now?

Twilightoptics · Posted: Mon Dec 31, 2012 5:17 pm Post subject:

Didnt you fix up the motor? If so its working more efficiently and needs a different tune.

You said you just have a tip in stumble now?

Fix the tip in and run it. If it sputters when steady cruise then up the primary jets.

izcain · Posted: Mon Dec 31, 2012 6:47 pm Post subject:

91RSVert · Posted: Mon Dec 31, 2012 6:49 pm Post subject:

I think the sputter was a plug gapped different then the others. Havent drove it since I did that.

I changed the base intake from a stock iron, to an eldbrock alumn.
I changed from points, to hei.

Rest of the motor is unchanged. Just cleaned up and new gaskets.

chevymad · Posted: Mon Dec 31, 2012 6:56 pm Post subject:

Carb has also been changed from the stock configuration and you are assuming the last guy did it correctly.

Quasi-Traction · Posted: Tue Jan 01, 2013 5:53 pm Post subject:

Three things:

1) assuming the motor is basically stock, a 59 primary and 60 secondary jets sound way too lean to me. I ran a 600 holley DP on my last G/f's 63 Falcon with a 260 in it, with a 61 primary and 66 secondary. And it was bone stock. (Her's was a manual trans, though)

2) for off idle tip-in, squirter size is more important than accl pump cam in my experience. Assuming the motor has a cam below .225 @ .50 on the intake side. Smaller numerically, longer duration of pumpshot, but smaller volumetric quantity of fuel. Stock motors usually work best with a long shot from the squirter on the primary, and the same, or one stage larger on the secondary squirter.

3) Start with the standard (6.5Hg if i remember) Power Valve on the primary side, and check from idle tip-in to transfer (when the power valve kicks in) circuits for vacuum drop. Double check timing and, step up or down with PV based

(also, as brandon and paul indicated, check off-idle tip-in with the secondary lever on the throttle bracket disconnected. Tune primary first, then fine tune secondary)