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Super Six VS 4bbl
https://slantsix.org/forum/viewtopic.php?t=33252		 Page 2 of 3
Author:  rock [ Sun Jan 11, 2009 6:23 am ]
Post subject:  Northern, Reed, Ted, and all,
Is there a mileage difference with the Offy intake? Well, it is hard to partition to intake only when one is changing a carb and an intake at the same time. Ted asked me awhile back about my mileage and vehicle weight, (and Ted, I re-found the email over New Year's and am collating the data).

Like 'zilla, I have no doubt there is a real kick in the a-- with the 8007, particularly with a build as mine made for low end torque (below 3,000 rpm). I had it with the 833OD and I have it now with the 727, whether braking and revving before the jump or just from idle.

I don't remember whether it was DI or Reed, but I can confirm that you can go from "bad" mileage (12 - 14) mpg to "good mileage (16 - 19 mpg) back to bad by rejetting from a 60 down to a 50 and then back up to what in my case seems to be "good", a 55. I don't do highway runs, just some town time and some "time trials".

You CAN get "bad" mileage by being too lean and I wasn't sure I was too lean until I got the wideband A/F. Unfortunately being too lean then richening up slightly caused me to have to change power valves. I am about settled on 6.5 but don't have it in this week. The 10.5 and 4.5 power valves....uhhh, embarassingly bad mileage, as in 10 mpg. After a year of tuning and roadwork I am convinced that for me I have to carefully plot advance curve, vac, A/F ratio, and rpm to be able to relate the effect of any one change.

So, Northern, my point is I personally wouldn't buy a brand new 8007. Since you say you like tweaking things, get a used one and Emanuel's and Urich's books on Holleys and strip yours and learn what is in it. When you have all the pieces in your hands you will clearly understand the idle circuit and the fuel delivery process in the Holley. Then it is not a difficult carb to work on. I like to have several on hand, just like dizzies, so I can make tweaks and pop on the tweaked in place of the one in use before the swap. And just as with a wideband sensor, it is much more time effective to set up your dizzy curve on a Sun machine than on the engine. Keep your eyes open for one.

rock
'64d100
Author:  Reed [ Sun Jan 11, 2009 8:37 am ]
Post subject: 
Back when i had an Offy intake and a Super Six intake sitting side by side on my workbench, I took a micrometer and measured the height, width, and diagonal dimensions of the passage inside the intake runner. The Offy was noticeably smaller, although I don't recall the dimensions offhand.

Unfortunately, I was running the Offy on a motor which had a blown head gasket (I didn't know, the motor ran nice and smooth) so I can't really say. It was in a van and the van got 10-12 MPG, but it also had 3.55 rear gears. I would love to get my hans on another Offy intake and try it out again on a slant six vehicle. I may do that someday, but it will be ahwile.
Author:  73NorthernDuster [ Sun Jan 18, 2009 3:10 pm ]
Post subject:  Would this work
I see this carb on ebag and wonder if it would be suitable. It is a bit bigger at 450 cfm. Thoughts appreciated

http://cgi.ebay.com/ebaymotors/ws/eBayI ... 0144298106
Author:  Joshie225 [ Sun Jan 18, 2009 3:59 pm ]
Post subject: 
I have no experience with the 450CFM Holley, but it appears to me there is no vacuum advance provision on the carb pictured.
Author:  68barracuda [ Mon Jan 19, 2009 9:41 am ]
Post subject: 
I think this is the 465CFm version - the vac advance nipple is not screwed in - on my setup this carb pulled harder above 100mph - the 390 is more punchy lower down
Author:  rock [ Mon Jan 19, 2009 11:16 am ]
Post subject:  Fanie, I been lookin' at that and think you are right and
Fanie,

I think you are right from my only three experiences with those carbs. I liked the cfm number is why I had some, but as I think Dan pointed out to me in a note, they are kinda old. The Eddy 500 blew em away. That seller, regardless which name is the most negative seller I ever interacted with on ebay. We never got to the buy part. If I were to ask him/her about that advance fitting I bet I would get a angry note back that if I didn't know already I obviously didn't know enough to put it on and better hire a mechanic. I asked one time if he would put a secondary metering block on an 8007 before selling it to me, and I got a note back telling me he didn't mess with junk and wouldn't sell to people that didn't know enough to leave a carburetor alone. Wanted to know why I didn't buy a 4150 if I wanted one. I was shocked since the addition of a secondary metering block and quick change spring setup is so common and a Holley approved mod. As a real estate guy told me once, people do business with people they like.

rock
'64d100
Author:  Joshie225 [ Mon Jan 19, 2009 11:47 am ]
Post subject: 
Rock,

Even though this seller has a 100% feedback rating the comments in the the feedback support your negative experience.

Here's a few choice excerpts:

"BEWARE! Seller refused to leave feedback and was very rude and unprofessional!"

"carb was in good working order except the vaccumn advance fitting was missing"
the reply: "Reply by quicktriumph (Sep-02-08 12:44):
complainers like this are why we are trying to stop selling on ebay"

"The carb was excellent, however the sellers e-mails were spiteful and demeaning"
Author:  73NorthernDuster [ Mon Jan 19, 2009 2:50 pm ]
Post subject:  This is why I like you guys
Thanks for the input

I guess I will pass and continue looking for a decent 8007. There are a few on ebag now but the prices are a bit high...No rush I've got a few months till the snow melts..
Author:  rock [ Mon Jan 19, 2009 3:03 pm ]
Post subject:  Wow! Joshie, thanks! I hadn't looked and Northern..
Joshie,

Well, well! thanks for telling me! I had never looked but boy, do those comments mirror my responses from that seller. There are so many good fellows and gals out there there is NO reason to ever buy from that person. So Northern, they come around all the time. Check to see if they have Chrysler linkage, but even if not, they are real simple to fit out for our vehicles. I made my stuff but the Bouchillon Perf. Eng. one just works great if you buy it. Look at BPE webpage too for some nice fitup pics. If one of these carbs looks usable in a pic, it probably is, even if you have to rebuild it ($50 kit) add jets ($10) or even replace a throttle body! Unless in a fire or showing throttle defects, there is nuttin to fixin them.

rock
'64d100
Author:  DusterIdiot [ Mon Jan 19, 2009 6:45 pm ]
Post subject:  It's like night and day...for some reason...
I have run 4 carbs on the Hpak Duster and with best tune the 8007 390 is good for all around street manners with a short cam, good lower response, good mileage once dialed in, and good punch for the highway...

I just removed a Holley 450 which I had hoped would be a nice 'compromise' from the 390 (which left my vacc gauge at 5-7" at WOT...so I was 'under carbed' when testing the potential), wasn't as great as I had hoped... the mileage was a compromise between the 390 and a 600... (not 'bad'...but not great either), throttle was OK, vacc gauge finally would reach 0 at WOT...

Holley 600 cfm carb was OK for WOT testing (pulled pretty nice)... mileage was...well a factory 440 with the super trak pack in rush hour LA traffic would probably still beat me to the pump...

I modified a Holley 600cfm with all 4 annular boosters so it's like a 575-580 cfm carb... throttle response was very positive (almost like the 390)... mileage was marginally better than the 600, but not as good as the 450...

A 'mid-range' carb is Holley's only real weakness they don't really have a tryed and true mid-range carb (which makes things a bit manic-depressive I guess), unlike the edelbrock which can boast a 500 cfm carb with good manners...

Good Luck on your decision,

-D.Idiot
Author:  Aggressive Ted [ Mon Jan 19, 2009 6:55 pm ]
Post subject: 
D.Idiot,

Did the 390 get better mileage over the Edelbrock 500?
What were your mpg numbers?
Did you have to tune the Edelbrock 500 or run it stock?
What size jets did you end up using on the 390?

Thanks,
Author:  ceej [ Mon Jan 19, 2009 7:43 pm ]
Post subject: 
I'm running the Offy, not a Hyper Pak like DI.

The 390 Got better mileage combined than the 600 Carter. Right now I'm running the Carter in 500 CFM trim, so may have some input soon. The Edelbrock can't change the primary boosters like the Carter, so is a wee bit less adjustable.
The 500 Carter seems to go through fuel heavily in WOT T&T. Since I have the Speedo and Defroster problems solved, I'll do some reasonable miles with it for the next tank. :lol: I'll leave the commuter car for Linda for a couple days. I just have to keep out of the go pedal.. Grrrr.

From what I'm watching, cutting the primary back for 500 CFM has had an effect on the low RPM, or Launch. It is nowhere near as violent as it was with the boosters for 600 cfm. On dry pavement, the 500 won't turn the tires on launch. I run a locker on 3.50 gears. With the 600, I got a couple turns then hooked.

Mid range and top is stronger with the 500. The secondary is the same, though I rejetted the primary to the 500 annular booster. Either will suck the WOT vacuum to zip.

I will estimate that the 500 Carter will be similar to the 390, though it will perform better than the 390.

With the 500 CFM Holley 2300, the car is violent and pulls through to my imposed redline. Idle isn't good, and midrange is iffy. I haven't run the 500 long enough to find out what the mileage is. It runs too poorly. My guess is horrible.

I'm torn between running the Carter as a 500, since I drive the car to the track, and playing with a 390 cfm Holley 4150. Andrew sent me an odd ball 480-490 cfm 4160 to play with. It's next up now that I've had a chance to play with the G-Tech Josh loaned me.

My best on the track with my "Hi-Rise" and 600 CFM Carter was a 16.51 at Redding last year. With the Hi-Rise removed, on a single 1" aluminum four hole square bore spacer and the same Carter set up as a 500 CFM, I managed a G-Tech run at 16.55 and 86.5 MPH. I'm also at slightly lower altitude, and the air is remarkably colder. Hard to get a real comparison.

I have my old 390 available to play with, since a Toyota plugged the driveway, and I haven't mounted it on the wife's Chevy Pickup yet. :roll:

Primary jets on the 390 for the slant were 52's. Secondary Jets, 54ish. Orange cam, screw #1, 31 shooter, and played between Purple spring and short Yellow. Bog was noticeable on white.

It all depends on cam, cam timing, and advance curve. Compression, intake, exhaust choices, and what-not. :lol:

I'm considering buying an Eddy 500 AVS, to get the secondary moving earlier. I can feel the stock air valve come in. That's a bad thing. It should meld in so that it isn't like a "Kick in the Butt." I either need to take weight off the air valve in the carter, or get an AVS so I can adjust it in sooner.

Not the answer you wanted? I'll keep trying. :lol:

Best Wishes! :D

CJ
Author:  rock [ Tue Jan 20, 2009 6:13 am ]
Post subject:  Northern, Ted and CJ, I run same stuff as CJ
Northern, Ted and CJ

As the saying goes, great minds in same track! A year's trials got me to what CJ is using; "Primary jets on the 390 for the slant were 52's. Secondary Jets, 54ish. Orange cam, screw #1, 31 shooter, and played between Purple spring and short Yellow. Bog was noticeable on white."

Ted, the 500 Eddy gave me about a mile per gal llower than the 390 cfm Holley 8007. I liked the Eddy better but not enough to get into recurving for it now that the Holley works so well. My basic problem is stomping it or fun. When that vac goes to zero and that jump comes in,.....but Ididn't build for mileage. I am going to have to tweak the power valve one more time, but I think the darn 6.5 is going to be the compromise choice. So Ted, if I had the 500 Eddy on, I would leave it now, but since the 390 cfm 8007 is on, well I will leave it. In fact I sold both Eddys I had to remove the temptation. I have a L9696 Holley that is a 450 cfm economaster, but I am going to get rid of it too and stay with the 390 cfm.

rock
'64d100
Author:  Terencejiminy [ Tue Jan 20, 2009 7:59 am ]
Post subject:  Re: Thanks
Quote:
Thanks for all the replies. Since the price of $150 sounds good for an offy I guess I will pick it up and hide it away until I get the itch to do more tuning on the car and can save up enough $$$ to buy a band new holley 8007 carb.
I really like tinkering on it..one of my only hobbies (other than hiding parts from my wife) so what the hay I guess I will be back with more questions when it comes time to re-curve etc.
HMMMM maybe I can find a hiding spot for one of those hurricane intakes somewhere too....lol
Thanks again
Cheers
Brent
Brent,
With racing on local vaca for a while :cry: you may want to jump in your 4X4 (or wait for a thaw) and pop in at Precision Automotive in Windsor and rap with Bobby V. there.
He's been on the pulse of my long rod 225 build up (did my head too) and has had some great input. :D
519-978-0050
Terry
Author:  ceej [ Tue Jan 20, 2009 11:47 am ]
Post subject: 
Hey Rock,

what is your in gear idle vacuum? I ask, 'cause a 6.5 power valve is going to have a terrible dead spot in the pedal. (Unless your car weighs like 900#) :lol:

The rule of thumb is 2" lower than cruise vacuum. It will tend to be pretty close to in gear idle vacuum.

I've been running 10.5's in the 390 and 600 Holley 4160.
A 9.5 tends to have a lean spot when rolling the throttle on. Anything lower than that, and driveability goes out the window.

If I could get a standard flow PV in a 12.5, I'd buy it in a heartbeat!

CJ
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