So you thought you could tune a Holley

[turbo2256b]

I have just started getting serious about tuning my carbs. Some issues have held me back. The main one finding the correct spark plug. Looks like got some finally that are close. Untill now could only find ones too hot or too cold. I have been fooling with the timing a bit. Timing and jetting all work togeather along with the plug heat range. Driving style or vehicle use can determine wether timing or jetting takes presedence in the final tune.

Here is the set up. I have already made some changes to the idle curcuit and its almost spot on for this set ups use. Will get back to it later as all the curcuits become closer to right on.

[Grand Marquis GT]

That's a nice lookin' setup. Real nice.

[turbo2256b]

That's a nice lookin' setup. Real nice.

Thank you

[zoomie]

nice setup there mang reminds me of the setup that my buddy will be running, but on a much more expensive scale

[turbo2256b]

Here is the air cleaner removed. Whats up at this point is the main jetting. Most just jet them up or down based on full throttle runs. This is good for drag racing for the most part. This is a street , autocross, open track with some drag race use vehicle. The tune has to go deeper into the circuits. Mostly for the fact good low end is needed for sharp corners were one has to slow down to mabe 20 MPH then run down a straight. For the street this can be good for economy too.
Notice the carbs are not stock. I have done such mods to single carb set ups but in this case I sent them out to be modified. Why because two carbs although they are the same make model can be as mush as 25% different in other word faternal twins. I dont have the equipment to make them identical twins. So one of the oldest carb moding shops made them identical. What is done to one has to be done to the other one to keep them matched. Although they flow and meter the same there is one issue. They are not flowed togeather they dont have the setup to do that few if any do.

[zoomie]

Here is the air cleaner removed. Whats up at this point is the main jetting. Most just jet them up or down based on full throttle runs. This is good for drag racing for the most part. This is a street , autocross, open track with some drag race use vehicle. The tune has to go deeper into the circuits. Mostly for the fact good low end is needed for sharp corners were one has to slow down to mabe 20 MPH then run down a straight. For the street this can be good for economy too.
Notice the carbs are not stock. I have done such mods to single carb set ups but in this case I sent them out to be modified. Why because two carbs although they are the same make model can be as mush as 25% different in other word faternal twins. I dont have the equipment to make them identical twins. So one of the oldest carb moding shops made them identical. What is done to one has to be done to the other one to keep them matched. Although they flow and meter the same there is one issue. They are not flowed togeather they dont have the setup to do that few if any do.

[ATTACH=CONFIG]29580[/ATTACH][ATTACH=CONFIG]29581[/ATTACH]

im digging the master cylynder man whered you get that?

[turbo2256b]

im digging the master cylynder man whered you get that?

Wilwood but lets try to keep it on topic to avoid confusion. Possibly start a thread to ask whats this or that under the hood would be good for all

[johnunit]

Ok so what was actually done with them? What does going deeper into the main circuit mean?

You say a lot but it sometimes isn't telling us much about anything.

[1987cp]

Davey! Long time no post (here)!

I don't remember, are you using a progressive linkage with those carbs? A distant relative told me of an experiment he did with two AFBs and a 1:1 linkage; he must have had one heck of a time getting that running nicely for street use.

Logical about plug choice making a good bit of difference. I found a website a while back with pics allegedly showing whether the timing was happy according to where the sparker ground strap changed color. Assuming that's a valid method (and I'm taking it into accoutn for now since it's the only I'm yet aware of), will a colder plug generally look "happy" with more ignition lead?

[turbo2256b]

Ok so what was actually done with them? What does going deeper into the main circuit mean?

You say a lot but it sometimes isn't telling us much about anything.

Deeper into all curcuits fine tune them to blend togeather as they were intended to do. Be patient Luke. Setting the stage ...might even help to read some of it twice. Fingers have had it to day texting is getting tuff

[turbo2256b]

Well decided to order some more Quick Fuel high flow 4 window power valves. So waiting on parts to reassemble. On to what I am up to.
The main curcuit in a Holley as well as most carbs is more of a light acceleration/cruse curcuit. Light acceleration might be something like running keeping the acceleator to the floor maintaning just above the point at witch the power valve opens vs the top desired cruse speed.

A good tuning style vacuum gage is a big help. Selecting a proper opening point for the power valve is needed before doing the tune or blocking the power valve curcuit wit ha plug.

[turbo2256b]

In my setup choosing 90 MPH as max cruse speed. The power valve is a 6.5 so I will make runs keeping the vacuum gage around 10". It may dip to 6.5 but trying to stay away from the power valve opening. I will keep jetting down untill the plugs look lean or other things showing poor running. Crusing at a highway speed fuel economy will be monitored as well as in town if it drops the jet has become too small or if its too big it will drop. I will attempt to post some pics of what and were to look for signs of jetting on the plugs.

[Southern_Pride]

I'll be glad when you get this done. I've gone up 8 numbers on my jetting and it's close now but still screwy off idle.

[turbo2256b]

Davey! Long time no post (here)!

I don't remember, are you using a progressive linkage with those carbs? A distant relative told me of an experiment he did with two AFBs and a 1:1 linkage; he must have had one heck of a time getting that running nicely for street use.

Logical about plug choice making a good bit of difference. I found a website a while back with pics allegedly showing whether the timing was happy according to where the sparker ground strap changed color. Assuming that's a valid method (and I'm taking it into accoutn for now since it's the only I'm yet aware of), will a colder plug generally look "happy" with more ignition lead?

Its a one to one likage. One differance from most is they are 390 CFM carbs with rework though they are capable of flowing about 520 CFM each. Most start out with too big of a carb like twin 600s on a mild small block.

[import convert]

Its a one to one likage. One differance from most is they are 390 CFM carbs with rework though they are capable of flowing about 520 CFM each. Most start out with too big of a carb like twin 600s on a mild small block.

are you saying theyll flow 520cfm together or indivisually?