Foxy Green Foxbody Build

So the information came from Holley themselves, and it's wrong, and people just still blindly believe it? I just find it difficult to believe that actual carb builders could be posting about it on fb even recently.. you would think they would have learned right or wrong from actual real world testing

As i said before the last time i had carburetors on street/race cars was the late 90's .. so i have forgotten almost everything about tuning them other than my memory of the actual physical holley carburetors themselves, like removing the bowls to change jets etc. I also remember upgrading to a front 50cc accelerator pump on an 850 annular i had. With the front pv, i can't remember what i did

This info is everywhere ....

Step 2: Select the correct power valve
  • Find the rule: A common starting point is to divide your idle vacuum reading by two to get the power valve rating (e.g., 13" Hg divided by 2 is 6.5" Hg, so you'd use a #65 power valve).
  • Adjust for your needs:
    • For better fuel economy: Use the number calculated above or choose a slightly higher rating to delay the power valve opening as long as possible.
    • For a performance application: If you experience a hesitation or sag as you get on the throttle, choose a power valve with a lower vacuum rating to provide fuel sooner (e.g., use a #55 instead of a #65).
    • To fix "loading up" at idle: For engines with aggressive cams that have low idle vacuum (e.g., below 12" Hg), you might need a lower-rated power valve. Some tuners recommend selecting a power valve with a rating closer to the idle vacuum, like a #45 or #35.

Yeah, that's all crap (for street engines, I don't race).

A great way to set the PV is to drive at cruise and then load it up and see where that vacuum point is.

This isn't my idea, so I won't take credit for it:

With a vacuum gauge you can see, find a place where you can drive at a speed where you're on the jets, and has an incline ahead.
As you hit the incline, see where the motor isn't happy.
That's the PV vacuum...
 
I get it. But i don't know why some carb builders still go posting online that the power valve can have an affect and end up over fueling the engine not under wide open throttle. Why do they post that crap if it's not true at all and can't happen

It's one of those old-wives-tails that just won't go away. It'll get you in the ballpark in a stock or near stock application but for anything else I use the process that Steve mentioned.
 
This isn't my idea, so I won't take credit for it:

With a vacuum gauge you can see, find a place where you can drive at a speed where you're on the jets, and has an incline ahead.
As you hit the incline, see where the motor isn't happy.
That's the PV vacuum...

I always screw up something!

You want to perform this test with a blocked PV...
 
First drive tomorrow. Before it leaves the driveway making a little checklist make sure I don't go fuckin her up.

Start it
Verify timing
Adjust mixture screws
Once warm, set idle if needed, check timing again.
Confirm the off idle stumble is gone
Bring to 2k, 2.5k, 3k, verify timing is doing its thing.
Check temps, oil pressure, volts,
Roll out.

Long row through the gears taking her up to 3k between shifts, engine brake. 2nd gear 1500 to 4k half throttle pull a few times. More engine brake. Do a burnout in front of the police station. All while checking afr and trying not to squirt
You're missing the 7000rpm hit, drive the fucker how you plan on driving the fucker! 😎
 
Another irritating problem that can rear its ugly head...

Some of the baseplates now have transition slots that are too big.
From what I understand the billet baseplates are the worst offenders.

If you're not happy with the off-idle/low speed performance after you're done tuning, we can talk about that...
That's getting more esoteric, so it's probably best to leave it in the back of your mind for now.
 
One thing comes in my mind you want a street car or a race car you really can't have both with out a street car with nasty habits that your going to have to live with
 
One thing comes in my mind you want a street car or a race car you really can't have both with out a street car with nasty habits that your going to have to live with
Nasty habits it is then 😎
My 636 lift street cam was ok in my opinion, 836 shouldn't be an issue, it's only .2 of an inch 🤷‍♂️, fuck all to a carpenter, nail it !
 
Nasty habits it is then 😎
My 636 lift street cam was ok in my opinion, 836 shouldn't be an issue, it's only .2 of an inch 🤷‍♂️, fuck all to a carpenter, nail it !
I love a car on the ragged side gets more attention and it plays nice when you want to play .
A 10 sec street car is not shit these days but back in the 80s you never thought about driving it on the street but I did
 
Well.

She scoots.

Turns out you forget how to do a burnout so it lasted all of 1/2 second before banging the 6200 limiter. Not even worthy of posting the video.

Air fuel gauge decided not to work so I made sure timing was good and ran it. I'll let you know next drive to see what's really going on.
 
I love a car on the ragged side gets more attention and it plays nice when you want to play .
A 10 sec street car is not shit these days but back in the 80s you never thought about driving it on the street but I did
Yes, but a lot of the 10 second cars today are using boost also. Best mine ran was 11.7 but at 125+ mph so probably a high 10 second car. I drove it in town to work through 22 sets of lights, other than a bit lumpy it was fine to me but lots would say differently. The racing clutch with MT stickies made it a bit more difficult to get rolling but not bad.
What did you have?
 
Well.

She scoots.

Turns out you forget how to do a burnout so it lasted all of 1/2 second before banging the 6200 limiter. Not even worthy of posting the video.

Air fuel gauge decided not to work so I made sure timing was good and ran it. I'll let you know next drive to see what's really going on.
Use 2nd gear and be ready to shift into 3rd. It is a 4 speed with 2 overdrive correct?
So are you happy with the torque?
 
Use 2nd gear and be ready to shift into 3rd. It is a 4 speed with 2 overdrive correct?
So are you happy with the torque?

Not enough time to know. Honestly I expected it to feel a little more.. scooty.

Once I get around to really tuning it I'll see. Not like cold ass asphalt roads are a good judge. I'm getting used to 20 things at once. Fresh everything including engine. Trying to figure out what noises are normal from every side of the car. Detroit locker banging, exhaust burning my eyes, trying to figure out if tires are rubbing stuff or not.. overall just need more time
 
65
Yes, but a lot of the 10 second cars today are using boost also. Best mine ran was 11.7 but at 125+ mph so probably a high 10 second car. I drove it in town to work through 22 sets of lights, other than a bit lumpy it was fine to me but lots would say differently. The racing clutch with MT stickies made it a bit more difficult to get rolling but not bad.
What did you have?
65 rambler Amc 4sp 390 with slicks and hub caps it was fun to drive
 
Not enough time to know. Honestly I expected it to feel a little more.. scooty.

Once I get around to really tuning it I'll see. Not like cold ass asphalt roads are a good judge. I'm getting used to 20 things at once. Fresh everything including engine. Trying to figure out what noises are normal from every side of the car. Detroit locker banging, exhaust burning my eyes, trying to figure out if tires are rubbing stuff or not.. overall just need more time
Good for you Fox its been a long journey with ups and downs but it takes time to sort a new build congratulations 🎊
 
Not enough time to know. Honestly I expected it to feel a little more.. scooty.

Once I get around to really tuning it I'll see. Not like cold ass asphalt roads are a good judge. I'm getting used to 20 things at once. Fresh everything including engine. Trying to figure out what noises are normal from every side of the car. Detroit locker banging, exhaust burning my eyes, trying to figure out if tires are rubbing stuff or not.. overall just need more time
Ya, be careful, roads are shit now.
 
Fux all this stuff.

Two 20 minutes idle sessions, a 6 mile drive with stop signs, and another few minutes of idle

20251120_143436.jpg
 
The plug looks fine for 40 min of idle time.
My 428cj plugs would look twice as bad after 10 min of idle.
 
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