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PostPosted: Sat Apr 09, 2016 6:16 am 
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4 BBL ''Hyper-Pak''
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Joined: Sun Oct 13, 2013 11:00 am
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Location: Canada
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Has anyone split a clifford manifold in 1/2 ( two plenums, split with divider) ?
If it has been done how was plate anchored?
What would be the best position for carb (Primaries close to engine or vise versa?) My Carb is now sitting east /west, not front /back (primaries are close to drivers fender).
I'm looking to develop a bit more torque.
Engine has over sized valves, 10:1 compression, hooker headers, cam, 3.91, 3200 stall etc.
Ran 15.50 at 87mph in 68 Dart convert . Looking to improve 60 ft.

Thanks in advance

John

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PostPosted: Sat Apr 09, 2016 6:39 am 
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Joined: Wed Oct 23, 2002 7:57 pm
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Location: Waynesboro, Pa.
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What was you 60 ft.? Are you on street tires?

Plus I have no real answer for your carb question, but all of mine are primaries in the front. I have always thought for a street car the better fuel distribution would come from a setup with the primaries to the drivers side. And for a race car the secondaries to the drivers side. I know that there are cars with all configurations that run well. Again I have no real data, but someone else will chime in.

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PostPosted: Sat Apr 09, 2016 7:25 am 
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4 BBL ''Hyper-Pak''
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Joined: Sun Oct 13, 2013 11:00 am
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Location: Canada
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60 ft averages 2.4 to 2.5. I'm on street tires. Small burnout.
Launching with a bit of wheel spin.

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PostPosted: Sat Apr 09, 2016 7:36 am 
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I did it on my clifford hyperpak manifold to adjust the midrange torque and be able to fine tune the carb for street use...

I'm not sure you would see any benefit on a shorty clifford manifold for racing use. I would be more inclined to either go with slicks or drag radials, and or a wider tire to change the friction patch and prevent wheel spin...
I had the same problem with my duster, street tires are fine for stock and mild builds, but if you have a fairly torquey build, with a drag rear ratio you'll burn a few tenths spinning the tires at the line....going to a set of 10" wide drag radials in the back fixed that...now I have to fix the fact I can't keep a clutch behind the engine....LOL


If you do go to a tire that will help hook up, you may need to look at a driveline loop...if the tires are sticky and not wanting to move as easily, and the motor and tranny are pouring torque that direction, the next thing to go will be the u-joints.


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PostPosted: Sat Apr 09, 2016 8:03 am 
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Sounds like a nice buildup!

Something else is very wrong to only get 2.4 60 ft with that combo. Manifold splitting will likely only hurt you, or gains will be small in the low/mid range. I would look hard at ign timing curve and carb tuning. What is your cam centreline - degreed in? Ign timing curve numbers?

Lou

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PostPosted: Sat Apr 09, 2016 8:58 am 
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4 BBL ''Hyper-Pak''
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Location: Canada
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Good question on the cam Lou. Going to have to dig up my notes.

Unfortunatly cam is a 268 clifford .
I remember having to put more advance into it ( done with a cam offset bushing).
Cam was supposed to be 4 deg advanced (ground) as per cam card . Car was a dog (cranking pressure was 155psi) .
After advancing cam, cranking went to 180 psi. Getting 12-14" in drive and 19-20" at 3600 rpm on the highway.
Running engine to 5800-6000 rpm at track, with good mph at the top end of the 1/4.
Running a holley 600 with a light spring on secondary, ( car runs 12.5 WOT on A/F wide band) no stumble.
Running a MSD 6AL box ,stock distributor with lightest springs. Starting 12 deg all in by 1800 rpm 32 deg ( not pinging).
Valves are lashed at 15 and 16.

John

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PostPosted: Sat Apr 09, 2016 10:53 am 
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Might be too much advance. Have you tried 28 deg total w/mech? Also, 15/16 on valves is likely too tight, although not terribly far off since you have decent vacuum at idle. For drags, the best orientation is what you have now, although it does not make a huge difference. Front/back also works fine and is better for braking/cornering g's. This probably leaves the carb tuning as the culprit. I never had luck with any Holley 4bbl, and I did plenty of tuning. Edel 500 4bbl or hly 500 2bbl will likely help you all around, unless you are a wizard Holley 4bbl tuner. Out of the box, they are quite far off for a 225.

What is the car weight? How much head porting? How did you (personally) check the stall speed on the converter?

Lou

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PostPosted: Sat Apr 09, 2016 11:02 am 
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Location: Salem, OR
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Quote:
Running a holley 600 with a light spring on secondary,
Run a brown spring and see what the change is... I run one of these only for drag, but have put annular venturies in it for better "signal" since the engine is so small... the 225 really wants about 450 to 500, so it really only needs a partial secondary tip in... I have only seen one slant six that will take the full brunt and use the 600 holley, your build is very mild compared to that build...


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PostPosted: Sat Apr 09, 2016 11:23 am 
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4 BBL ''Hyper-Pak''
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DI,
I'll pull out my distributor springs and give the brown a go. I've never gone backwards on timing? .... another thing to try.

Lou,
I had big valves installed this winter. Also had head flowed. Got the best of 176 cfm at 450 lift. Head was home ported.
BTW my cylinder head guy found over sized stainless valves, some where in California. He had them in one week up here in Canada. I'll find out where he got them. Might be a good substitue for enginbdlr.

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PostPosted: Sat Apr 09, 2016 1:52 pm 
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Joined: Wed Oct 23, 2002 7:57 pm
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Location: Waynesboro, Pa.
Car Model: 65 Valiant 2Dr Post
Quote:
Something else is very wrong to only get 2.4 60 ft with that combo
I am not sure that is all that far off the mark if you are spinning?

I just checked some time slips on my car from last year. Our builds are similar but you have a little more compression than me and probably a couple hundred pounds more than me.

But I have drag radials and with no wheel spin I have a best 60' of 2.09 and mostly in the 2.1 - 2.15 range. I only turn 5200 RPM and I have run a best of 15.11 @ 86. Probably would go a 14.8-14.9 @ 6000 RPM, but I don't want another kaboom!

Get some good tires and give her a rip!! :lol:

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!
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 Post subject: That aint good...
PostPosted: Sat Apr 09, 2016 2:00 pm 
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Joined: Tue Oct 29, 2002 8:27 pm
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Location: Salem, OR
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Quote:
DI,
I'll pull out my distributor springs and give the brown a go. I've never gone backwards on timing? .... another thing to try.
Uh no, my subject was about the 600 holley...detune the secondaries by putting the brown spring in the pod and see if that helps your front end time....

I think a combination of timing per Lou's recommendations and having too much carb on there is a fair amount of the issue...with the brown secondary spring the secondaries will only kick in under extreme load...

What/ who's springs did you put in the distributor?

Make sure to make one change at a time to see if you are making progress so you don't have to undo everything to find out what went wrong if something didn't work...
Quote:
BTW my cylinder head guy found over sized stainless valves, some where in California. He had them in one week up here in Canada. I'll find out where he got them. Might be a good substitue for enginbdlr.
Those are SI valves, they are about 60% more expensive than Enginebldr valves, but I have yet to wear my set out in 15 years of running the head I used them in....(over 3 different engine builds...)


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PostPosted: Sat Apr 09, 2016 2:38 pm 
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4 BBL ''Hyper-Pak''
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Joined: Sun Oct 13, 2013 11:00 am
Posts: 25
Location: Canada
Car Model:
DI,
My bad... Running yellow spring racing and
Black spring to track (100 mile trip) . Found gas mileage went to 8 with yellow😮 spring.
Car gets 21 mpg on the highway with black spring😊👍.
Distributor springs are Mopar kit from a speed shop.

Once snow melts going to head to track. I have a Holley 390 I ran before.
Going to give it a retry.

Your correct on the valves. Head guy said they are SI.
They did the trick.

Now I'm nervous Lou. The BOOM. What happened ( rod,main?)
Thanks for the 60 foot times. At least I'm not super far off.

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PostPosted: Sat Apr 09, 2016 2:51 pm 
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Joined: Mon Oct 21, 2002 11:08 am
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Location: Blacksburg, VA
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Rick is right that it is hard to tell what your "real" 60 ft would be w/o good traction. Probably best to solve that first, then move on to other things. If you know the car total wt, w/driver and fuel, that will help understand the MPH and ET better vs. HP too.

Head flow sounds quite good. 5400-5600 is probably a good redline unless you have good parts in the bottom end - at least good rod bolts, balanced rot/recip assembly, good brand pistons, etc.

Slant on,

Lou

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PostPosted: Sat Apr 09, 2016 4:23 pm 
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Supercharged
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Location: Portland-ish
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I'd like to see video of the car launching. So long as we can see and hear clearly what's happening it should be informative.

Advancing the cam I believe was productive. The light springs in the distributor are fine, but I think that the mechanical advance is too much. To get enough initial timing without over advancing at high speed the advance slots invariably need to be shortened.

Like the others I'd solve the traction problem and then work from there.

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PostPosted: Mon Apr 11, 2016 4:27 am 
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Location: CBS Newfoundland Canada
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what is your mph to et? you sad your cranking pressure is 180 psi but what is your mechanical comp ratio? I found that a 650cfm double or 600cfm vac work a lot better than 390 for duel purpose. 32deg total at 2800rpm worked best for me but you have to watch your plugs, any detination you see not hear will affect your hp. if you have hood clearance 2in spacer will help.


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