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  #31 (permalink)  
Old 04-27-2013, 03:52 PM
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Rich 1-3, 2-4, lean 5-7, 6-8

Pulled the new Autolite AR73 .035 gap after the 1st and last ride (about 6 miles) after installing them. 1,3 and 2,4 are showing pretty rich but 5,7 and 6,8 are showing real clean almost like new. No wonder the AFR readings in my post #53 are so screwed up. I didn't find anything wrong with either carb since checking them a week ago other than had to lower float level on the front carb just a hair to get the 7/16 drill bit under it as shown in the carb manual. Didn't find any intake leaks either.
Another question, how much will the plugs clean up after correcting the fuel problem and reinstalling them. Can I depend on the reading from them after that. Good idea to clean them with carb cleaner or ?
The plugs in the pix are lined up as they came out of the engine. 1-7 on top, right to left, 2-8 on bottom, right to left. #1 has been lightly wiped with paper towel before I thought to take the pix.
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  #32 (permalink)  
Old 04-27-2013, 09:39 PM
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Quote:
Originally Posted by F-BIRD'88 View Post
The sparl plugs show the front carb was clearly flooding.
Dirt in needle seat/fuel pressure/ float setting fuel filter.

Those plugs are not carbon fouled and will not clean up.
You will not be able to further tune , useing these carbon fouled plugs.

Replace all the spark plugs with new. try again.

You are a long way away from playing with the air air door weights.
One thing at a time.
( when if you do get there you will need two spare air doors to work with as it is eaier to get it wrong then right and takes work. adding/subtracting weight.. Don't jump ahead.
Get new plugs and get some more driving afr tests.
Plugs are getting expensive. lol Rather not mess with air door weights if I can help it. Will get back to u after I get things straightened out.
Thanks for all your help.
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  #33 (permalink)  
Old 04-28-2013, 11:38 AM
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Originally Posted by thinwhiteduke View Post
You got one too many 750's



Duke
I agree totaly.1500 CFM is too much for a 355 even with all the goodies.
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  #34 (permalink)  
Old 04-28-2013, 11:42 AM
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Originally Posted by Fang16 View Post
It's all in the tune. I'm competent a good tuner well have something worthwhile to say.
Even a good tuner will tell you that you need to have the right fuel/air ratio.You have too much air and if you jet it down enough to get the bog out it will be too lean for top end and probably melt a piston.
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Old 04-28-2013, 12:14 PM
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Originally Posted by Fang16 View Post
Well, here we go. Been working on changing the stuff you advised. Please look at the attachments when you get the time. It still bogs of-course (when I rug it) but we're getting there. Drive ability is pretty good considering.
I never said a 2X4 tunnel ram won't work.I said you would be better off with smaller carbs.F-Bird absolutely knows more than me but I would like to hear his answer to this question.You jumped from 2 450s to 2 750s.Even though he made it work would it have been easier and better with 2 650s instead.Just like when he told you you were jumping up too many jet sizes at one time.
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  #36 (permalink)  
Old 04-28-2013, 12:44 PM
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Originally Posted by speedydeedy View Post
I never said a 2X4 tunnel ram won't work.I said you would be better off with smaller carbs.F-Bird absolutely knows more than me but I would like to hear his answer to this question.You jumped from 2 450s to 2 750s.Even though he made it work would it have been easier and better with 2 650s instead.Just like when he told you you were jumping up too many jet sizes at one time.
Yep, that was my mistake. Been away from tuning for over 30 years and got ahead of myself. That being said, Murphy's law has reared it's ugly head in this project a number of times also. I have 2 650's but would rather save them for the blown 350 I'm building. I also have 2 Edel 750's on my blown 350 29 Ford that I sat up long time ago that work great, but it is blown. Makes a difference.
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  #37 (permalink)  
Old 04-28-2013, 02:17 PM
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Heres an option - put your 650s on the tunnel ram and put the 750s on the blower project. The 750s will work good on the blower project.
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  #38 (permalink)  
Old 04-28-2013, 02:45 PM
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Quote:
Originally Posted by speedydeedy View Post
I agree totaly.1500 CFM is too much for a 355 even with all the goodies.
I think the standard for cfm is measured differently for 2bbl / 4bb / 2x4bbl induction. 1.5 inches is the calibration standard 1x4bbl. Using the same flow across two carbs , two 750s would pull about 850cfm total on that tunnel ram induction. The number of cfm the engine sees is dependent on the pressure drop between the carburetors.

850cfm is definitely okay for the application.

2x 600 would pull 700cfm on a tunnel 2x4.

My numbers are probably a little off, but do you get the concept.

Last edited by spinn; 04-28-2013 at 02:56 PM.
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  #39 (permalink)  
Old 04-28-2013, 06:54 PM
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Originally Posted by 33Willys77 View Post
Heres an option - put your 650s on the tunnel ram and put the 750s on the blower project. The 750s will work good on the blower project.
I'm contemplating that move. Have tuning kits for both.
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  #40 (permalink)  
Old 04-28-2013, 06:56 PM
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Quote:
Originally Posted by spinn View Post
I think the standard for cfm is measured differently for 2bbl / 4bb / 2x4bbl induction. 1.5 inches is the calibration standard 1x4bbl. Using the same flow across two carbs , two 750s would pull about 850cfm total on that tunnel ram induction. The number of cfm the engine sees is dependent on the pressure drop between the carburetors.

850cfm is definitely okay for the application.

2x 600 would pull 700cfm on a tunnel 2x4.

My numbers are probably a little off, but do you get the concept.
Yep, understand where your coming from. Thanks for the help.
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  #41 (permalink)  
Old 05-01-2013, 06:53 PM
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Quote:
Originally Posted by F-BIRD'88 View Post
what is the file name and addy of the most recent file you want me to look at.?
The one with the 600 carbs on the motor.

what is the defect on the 750 carb? If it is a real manufacturers defect like a casting flaw/Edelbrock may replace it for you.
But you have to ask.

Open up the AFR text file and edit it by writting in showing aprox throttle position/engine load/driving mode/rpm
In each area so I know what the engine is doing.
resave and
post the AFR file txt here.
That is the easy way for me to evaluate it.
The main one was the T slot on the left had a casting flash (bump) that blocked the
the T slot when the throttle was at idle, would'nt even let it close all the way. Closed on the left and .060 T slot on the right. Also found a hairline crack on that side where the IMS is.
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  #42 (permalink)  
Old 05-02-2013, 02:52 PM
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Sure seems reasonable that DCR's and vacuum plays a major role in tunnel rams.Proper cam selection limiting revision should be critical.While a tunnel ram wants to run in the upper RPM ranges possible the cam doesn't or the reverse could be true.That has to be a good match for it to work.
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  #43 (permalink)  
Old 05-02-2013, 04:45 PM
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Quote:
Originally Posted by F-BIRD'88 View Post
The WOT afrs look ok. For this one test.
It shows you are in the ball park @ WOT. But drag testing (MPH) will show you what WOT jetting
works best. (The afr gauge is just a guide) It is just one of your tuning tools. There is no perfect WOT AFR to target. Some engines like a bit more or a bit less WOT jetting. Thats what drag strips are for.

Try the new jetting I recomended for the 600's and tell me how it does.
Will get back on it tomorrow and change the jets as u suggested. Not sure when I'll be able to try them though. Gonna be a cool rainy week.
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  #44 (permalink)  
Old 05-03-2013, 08:15 AM
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We got all the nice weather this weekend.
In Canada there are 3 seasons. Winter , Road Construction, and Patio !!
We set a record today. Woke up to some or your Canadan weather down here. Bout .3 inch of snow, in MAY!
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  #45 (permalink)  
Old 05-06-2013, 05:17 PM
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Finally cleared up to where I could get back on it. Reversed the jetting as you suggested from the 95-98 to 98-95, 70x37 needles and 4" springs and reset idle. Been running a vacuum gauge for a while now. Idle vacuum is 9.5-10" and cruise is the same. Here's the latest LM2 logs for your perusal. lol
appreciate all your help and time.
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