Horrible....simply horrible. I was hoping for more but the initial run gave me 88hp @90mph , to the wheels. After some timing issues we got her up to 94hp @ 90mph. Dyno guy thought I could get more, he told me at full throttle I was at 6" of vacuum, he said I should be at .5 - 1" for maximum pull. We went for another round and he told me to watch the secondaries cuz she doesnt feel right, when he punched it to 4300rpm the secondaries were still closed, So I reached over and opened the linkage and the motor came alive, got her up to about 5200rpm with 115hp.

So the issues are my bad vacuum diaphragm, changing my power valve from a 5.5 to a 8.5, and looking into a edelbrock 500-600cfm 4 bbl. Dyno guy said if i do the edelbrock route I should be looking at about 160hp to the wheels. In my next life im gonna own a dyno shop, for $125 bucks an hour, I would be a rich individual.

<img src="http://members.aol.com/Pyper70/Duals.jpg"width=400>

There was a guy with his runs at the SSCOA meet in a mid 60's S-body wagon with a similar setup to what you have. He was more interested in mileage though he was pulling something close to the 80-90HP at the rear wheels, but getting 26-31 mpg... He was using the 8007 holley 390 with 52's front and 54's back I think.

Just from my experiences running a holley on the Hpak, a 10.5 PV is just about mandatory for any of those carbs on a slant, 8.5 is great for mileage. Your secondary spring should be either yellow or purple.

what did you set your timing at and what distributor are you using.
I noticed if using the stock mopar EI distributor you need to change the springs and file the slots open and give it more initial to get the magic number of 32 mechanical and 55 total. This really wakes things up from the stock 28 mech + vacuum....

Cool to get some numbers... yep the runs are $$$, there are a few in our area. The prices range from $50/hr (full day/8hrs min.) to $100+/hr...

cool!

-D.Idiot

I just got my Edelbrock 500/offy/Clifford headers going. I'm not sure, but I think my secondaries are not opening either. Is there a simple way to test/fix this?
Do you have any head or cam work? I'm curious if there is a difference between the Offy and the Clifford in take. What mufflers are you using?

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"Nothing in all creation is hidden from God's sight. Everything is uncovered and laid bare before the eyes of Him to whom we must give account."

my timing it set at 40 total, my distributor is a Mopar Elec Ignition, MSD 6a, Blaster coil.

I had my cylinder head done about 2 months ago. had it milled .060" (brought it up to 9.3:1cr) 1.70/1.44 valves Si's, Stage 1 porting, and a 5 angle valve job. MP Purple cam .436 lift, Holley 390 cfm, purple spring, 51 pri's / 53 sec's, 5.5" PV, Offy 4bbl Intake, Tri-Y Cliffords.

Pete

first off, your jets are off. i'd go up to about a 55ish with that combo in the primaries. not sure what vac reading your getting at idle and in gear but i'd hazzard to guess a 7.5-9.5 PV would be best. also if the secondaried arnt opening, it means you have to go lighter on the spring. next time you go to the dyno, buy a spring kit and bring some jets with you. also a timing light would be good and maybe a spare dist with different springs/etc in it (PUT MORE ADVANCE IN IT!). What gears are you running out back? and also what converter do you have?

With that combo you should be able to hit high 15's in the quarter mile and around 160+horse pretty easy. I'm going to go and Dyno my volare with 2.76 rear gears, stock converter, with JUST a offy intake/600cfm holley added. i hope to turn close to 110hp with it all tuned in, after i bolt on my 3.55's, cyl head (ford 300valves, decked .110, and the equvilent of a stage 2 port job, the cam is still undecided for my combo, i'll have a rebuilt 904 with a B&M manualpak + 3000rpm stall converter, i hope to turn alittle over 200hp with that setup.

kinda sad when ya think about it, with a 318 you'd probably be making closer to 350 but then again, any idiot can make a VEEEE8 go fast!

Justin

it has a purple spring in the vac secondaries, the jets are fine, im not rich, im not lean, im perfect, i didnt touch the car, the dyno guy did it.

3.23 gears

1800 stall stock converter

Vac at idle ... 15"

vac in drive .. 13"

vac under full load .. 6"

Justin while I love my /6 to death I can sympathize with the v8 crowd just as easily. It's not just about making it going fast but the price:performance ratio with a 318, or any small block for that matter is a lot more attractive then with a slant. You can get 300+hp out of a stock 318 + with headers cam and carb.... 300hp (n/a) out of a / will take lots more effort then that.

Pierre, yea i know what you mean about this V8 thing, it really is appealing to me and probably many other people, i was dead set on the slant, but after alot of the low performance #'s i hear its nutz, think about it, you could by a stock 4dr sunfire with 140hp and our slant makes like 120 stock with 2 more cylenders but then again, we have alot more reliability, virtually anyone can work on one,and they're CHEAP, not only that, but they are something different. i'm dead set on my slant and will never give up on it, however if i do get a 2nd car, i'll probably look for a 340 or some other SB mopar.

Pyper6970

Trust me on saying that the jets in the Primaries are too small for what your running, my stock slant is running with 52's and thats perfect all around. as for the Powervalve thing, with 13psi @ idle in drive, you should be with a 9.5PV (you should cruse @ 60mph @ around 10-11psi if properly jetted ) you should have your secondary jets a full six sizes larger than the primaries to start with, and the spring for the Vac secondaries should be ligher if they arnt opening. the reason your getting 6psi of vac @ WOT is because the secondaries arnt opening.

More later.

Justin

I assume that the dyno had some way to measure the air/fuel ratio? If so then you don't need to change the jets. The jet size that someone else runs doesn't matter, only thing that matters is what the A/F ratio is.

The 6" of vacuum at WOT is bad news. You definately have a problem there. If you have that much vacuum at WOT and your PV was a 5.5 then you could potentially shut off the power valve at WOT and lean the motor out enough to torch the valves. This happens sometimes to racers who are using a carb that is too small. In your case, the carb is plenty big, you just have something else that is wrong.

A small Edelbrock or Carter carb would seem to be a good choice for this type of setup. They have mechanical secondaries so that elminates one issue but the really nice thing about them is that they are much faster to dial a fuel curve into than a Holley. Time is money on the dyno. I have an AVS carb on my car and it is really nice to dial in on the dyno. I'm at 460 hp at the rear tires but that isn't fair since it is a V8!

dunno, 51's are pretty small.. I wouldnt count out the holley nor ditch it. you have it so stick with it (99% of racers use holleys for a reason ), going to a carter or edel wont do much but confuse you, they have alot more parts than a holley ever will!

andyf is right about the 6" at WOT thing, your not using your PV wich is a bad thing. what equipment did the shop have? (A/F meter, vac guage, timing light, etc hooked up?) creat a list of things to get before the next "pull" some jets (belive it or not A/F ratio doesnt mean everything when trying to make HP, its more of a "economy thing" however it does help) a spring kit (these come in handy and are fairly cheap) (I think 30bux or something) and a quck change spring kit if you dont already have. i have 100% belief that you can make that setup turn 160hp fairly easy.

Justin

I wouldn't argue with Andy...we both know the top dog in our area runs a mopar with a Ford rear end and a QuadraJet .....

Get 'im andy!

-D.Idiot

On the V8 thing, I've been fighting with that question. I actually think a dressed up V8 looks better than a slant six, is faster, and probably just as fuel efficient as a extremely souped up Slant Six. If I remember right the most that a slant six can be souped up for is the 300-400 horsepower range. The thing is, I like the Slant six because, as it's been said, it's different, and it's very reliable, but it costs a fortune to build. I don't know, I'll figure it out when my engine blows and I'm forced to make the decision, build the Slant or buy a V8, then again, with the reliability of my Slant Six It might be fifty years before I have to make that decision.

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My car may be slow to sixty, but at least it's been reliably slow to sixty for more than thirty years.

He had an A/F digital scope, the timing light, I have a vacuum gauge in my dash. At idle i was 11.6 which is rich, but under WOT i was 14.2 (near perfect) After giving her a little more timing the Vac dropped to 4" @ WOT. he did recommend going to an 8.5/9.0 PV. At first glance he thought the carb was too small but when we realized the secondaries weren't opening, we found the culprit. I took off the secondary diaphragm assy. today. The check ball is missing, the diaphragm is intact with no tears, I replaced the purple spring with a shorty yellow (the softest spring in the holley kit). The only thing I can guess is that the passage that runs the vacuum to the diaphram is somehow blocked. How else would I be able to trouble shoot the secondaries while it still being bolted to the car, this is my daily driver, cant afford any down time really. Thanks for the infor guys, I really do appreciate it.

Pete

You're options on the PV are 8.5 and 10.5 they no longer make a 9.5 with the 595 type valve. Purple spring should be OK, you just want to step down one at a time, on my setup the soft spring flopped the secondaries open and caused a nasty bog off idle, so I vacilate between long yellow and purple.

My 8007 never had a check ball either, I think this is due to the size of the carb, my 600's either had a 'brass plug' with a pin hole where the check ball was or had a check ball.

You might check while the carb is bolted to the manifold and the ignition off, open the primaries all the way then open the secondaries slowly by hand and see if the linkage is 'hitting' something, binding up. I'm betting the diaphragm might be shot. If you buy a new one, grab a secondary quick change pod kit. For $10 this kit has allowed me to change springs with a screw driver and 3 minutes without removing the carb and pod to make the change....

-D.Idiot

If I read your post right, you said mixture was 14.2 at WOT. This is quite lean. You need around 11.5-12.5:1 AF for best power. 14.2 is good for cruise or light accel or idle.

Also, 40 degrees total adv (not including vac, which should be disconnected for dyno pulls) is WAY too much. This could have cost you 20-40 HP. No slant should run more than 32 deg total adv, and I usually run my motors in the 28-30 deg range for max power (14 sec 1/4 miles).

This summer I went to the drags and had the timing 6-8 deg too far advanced (36-38 total) and the car went 15.50. I changed nothing else, and retarded the timing 8 degrees and the car went 14.55.

Lou

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