289 upgrade to 4bbl

[barnett468]

you definitely don't need a posi diff for your app.

as was mentioned, the base eddy 4v aluminum intake is basically the same as a cast iron factory one and a hi po will spin 6000 rpm with a cast iron one so it really is about as "big" an intake as i would use for your app . if you want one that is slightly "bigger, the weiand street intake is one of a few good choices.

an eddy rpm intake is way too much.

[BAC]

You also suggest another Carbi with adjustable secondaries (not that I realy know what that means)

4 barrel carbs only operate 2 barrels (primaries) until a certain RPM figure is reached (based on vacuum, throttle opening, etc.) then the other 2 barrels (secondaries) cut in as well. Typically carbs that have adjustable secondaries do so by having a spring whose tension must be overcome for them to open.  The adjustment is gained by switching heavier/lighter springs to get them to open at higher/lower RPM.

[GEOFF289]

I think you are saying below 3.00 gears ok and I dont need the diff lock?

I think he means that with those changes you'll still have relatively modest power and won't need a locking diff regardless of ratio.

Have a look at this about vac secondaries

https://www.holley.com/blog/post/how_to_adjust_holley_carburetor_vacuum_secondary_springs_/

[mcarnage59]

4 barrel carbs only operate 2 barrels (primaries) until a certain RPM figure is reached (based on vacuum, throttle opening, etc.) then the other 2 barrels (secondaries) cut in as well. Typically carbs that have adjustable secondaries do so by having a spring whose tension must be overcome for them to open.  The adjustment is gained by switching heavier/lighter springs to get them to open at higher/lower RPM.

Yep got it thanks. Both Brian and Geoffs explanation spot on. So what controls the secondaries on an autolite 4100 as Barnett indicated they are not adjustable? and what Carbi is recommended. The one boofhead suggested?
BTW Geoff I contacted the diff place in Geelong and he can provide a centre with new bearing for high $5's so thanks for the referral.

[GLENN 70]

Have you pulled most of your hair out yet with all the different answers    . If you want it to look stock and go well ,buy the original set up .  The edelbrock performer intake works about the same as the ford intake ,but is alloy and doesn't have the four holes but two open ports .    The edelbrock performer and a 600 square bore vacuum secondaries Holley  is what I would go for .  Either extractors or K code exhaust manifolds .  The edelbrock carbs are good but not many people know about them here in Australia .  Going from the 2.8 gears to the 3.00 may not be worth it ,200 rpm lower at 100 kph .  Me myself and I would go 3.25 and if I was not happy I then would go a taller rear tyre ,like from 25 inch to 26 inch .  Setting the timing up compared to factory setting will help also .  So many answers I know 

[BAC]

Going from the 2.8 gears to the 3.00 may not be worth it ,200 rpm lower at 100 kph .  Me myself and I would go 3.25 and if I was not happy I then would go a taller rear tyre ,like from 25 inch to 26 inch .

  If you're going to the effort and expense of changing the diff ratio, go for something where you will notice the difference for sure.  As Glenn says, if you find it a bit too short you can always go for a larger tyre.

[barnett468]

So what controls the secondaries on an autolite 4100 as Barnett indicated they are not adjustable? and what Carbi is recommended. The one boofhead suggested?

There is a spring that controls the opening time on the holleys and the ford carb, however, there are no aftermarket springs for the ford carb to change the timing of the opening and they are designed to open fairly late so you hardly even notice it because it is high in the rpm range . holley makes springs that fit the holleys and quick fuel carbs . those carbs also come with a spring that causes the secondaries to pen fairly late so in most caees, you will get more power lower in the rpm range if you install a lighter spring which allows the secondaries to open sooner and the most common spring that most people install is the white one but in some cases that allows them t open too early causing a slight bog/hesitation when they open so you must test the springs by flooring the car from a stop until it shifts into second . keep installing lighter springs until it bogs slightly when the secondaries open then go up one spring rate and call it a day.

also, it is easy to get jets for holley and quick fuel and they interchange with each other meaning that you ca use holley jets in a quick fuel carb and quick fuel jets in a holley carb, HOWEVER, they do not use exactly the same metering system . this means that a 60 holley jet flows slightly less fuel than a 60 quick fuel jet so when you start jetting you need to use only quick fuel jets or only holley jets or you will never get it jetted right . no one knows wtf quick fuel did this.

Here they are and an estimate of opening time in rpm. They don't rate the white spring because it opens really early.

[evan]

I had no trouble finding Autolite jets when I rebuilt my 4100:

http://stores.ebay.com.au/Partsdencom/_i.html?_nkw=autolite+jets&submit=Search&_sid=1026936301

Evan.

[mcarnage59]

Have you pulled most of your hair out yet with all the different answers    . If you want it to look stock and go well ,buy the original set up .  The edelbrock performer intake works about the same as the ford intake ,but is alloy and doesn't have the four holes but two open ports .    The edelbrock performer and a 600 square bore vacuum secondaries Holley  is what I would go for .  Either extractors or K code exhaust manifolds .  The edelbrock carbs are good but not many people know about them here in Australia .  Going from the 2.8 gears to the 3.00 may not be worth it ,200 rpm lower at 100 kph .  Me myself and I would go 3.25 and if I was not happy I then would go a taller rear tyre ,like from 25 inch to 26 inch .  Setting the timing up compared to factory setting will help also .  So many answers I know 

Dont have any hair   Yes there are a lot of opinions, but its great that you guys are prepared to take the time to offer them. My wife has the shits cause I spend my nights with my head in the computer reading this stuff these days. Its either iteresting and educational or interesting and very amusing (the Fitzy build should be made into a telemovie)
As I have tried to explain my requirement is at the low end of the scale in regard to Horse power and performance. Just want a little zing. I have probably confused the issue by saying stock look when I alreay have put aluminium valve covers and a hipo aricleaner, so stock but not stock :therethere:I will consider your suggesting re: gearing but dont want it revving its guts out on the freeway. I can get a cast 4bbl inlet from a club member so will probably proceed with that and later get the hipo exhaust mani. So just need to decide carbi and gearing. There is a lot of different opinion around carbi thats for sure.

[BAC]

I will consider your suggesting re: gearing but dont want it revving its guts out on the freeway.

Assuming Glenn's calculations are correct that you're currently pulling around 2300 RPM @100kph with a 2.8 diff, going to a 3.25 would increase this to a tick under 2700 RPM. Still quite liveable IMHO but your choice of course.

I can get a cast 4bbl inlet from a club member so will probably proceed with that

Again your choice but if you're going to change, a Weiand stealth will be much lighter and get you a few more HP for similar money.

There is a lot of different opinion around carbi thats for sure.

Sounds like you need another one:  https://www.summitracing.com/int/parts/sum-m08600vs/overview/ 

Should be perfectly sized for your app and comes ready to run out of the box.  $460 AUD delivered to your door and check out its customer feedback rating.

[mcarnage59]

Assuming Glenn's calculations are correct that you're currently pulling around 2300 RPM @100kph with a 2.8 diff, going to a 3.25 would increase this to a tick under 2700 RPM. Still quite liveable IMHO but your choice of course.

Again your choice but if you're going to change, a Weiand stealth will be much lighter and get you a few more HP for similar money.
http://www.ebay.com.au/itm/WEI8020-Weiand-Stealth-Intake-Ford-Windsor-Small-Block-V8-289-302-/191904651275?epid=1563475195&hash=item2cae68980b:g:DWgAAOSwDk5T9CB~
Sounds like you need another one:  https://www.summitracing.com/int/parts/sum-m08600vs/overview/ 

Should be perfectly sized for your app and comes ready to run out of the box.  $460 AUD delivered to your door and check out its customer feedback rating.

[GLENN 70]

Say what ,if I'm correct     

[mcarnage59]

Say what ,if I'm correct     

The guy in Geelong that Geoff recommended wants $1100 complete job including new wheel bearing using Italian gears. I think I will go 3.25

[GLENN 70]

I think he was talking about thr engine revs ..  Try this .  100 kph /62 mph .  62x3.25x336 div by 25 = 2708 rpm . Or 62x3.00 x336 div by 25 = 2499 rpm @ 100 kph . That's the formula I work on and for 30 + years .

[GEOFF289]

The guy in Geelong that Geoff recommended wants $1100 complete job including new wheel bearing using Italian gears. I think I will go 3.25

When I said a grand I was of course talking GST exclusive.

You need to go down there Brian.

[mcarnage59]

When I said a grand I was of course talking GST exclusive.

You need to go down there Brian.

He has a two to three week back log so just have to wait

[BAC]

When I said a grand I was of course talking GST exclusive.

You need to go down there Brian.

Does that include all labor for drive in/drive out service or do I have to crack open the diff myself?

[mcarnage59]

Does that include all labor for drive in/drive out service or do I have to crack open the diff myself?

Drive in drive out, need to leave it there 3/4 days. Gears/Bearings and wheel bearings as well. $600 for centre do the work yourself. I think its a very good deal at $1100

[BAC]

Drive in drive out, need to leave it there 3/4 days. Gears/Bearings and wheel bearings as well. $600 for centre do the work yourself. I think its a very good deal at $1100

Yep - can't argue with that!   

Please post or PM the guy's details for future reference.

[GEOFF289]

I did.

http://geelongdifferentials.com.au/

[BAC]

Thanks Geoff - I missed that post. 

[barnett468]

I think I will go 3.25

ok, xlnt, a decision. you may very well find that you wont want to do anything else after this so as i mentioned, you might want to just try the gears before making any other changes.

also, if you ever go to slightly larger diameter tires, you wont loose all the power you gained like you would if you used 3.00 gears than went to a taller tire.

 

[mcarnage59]

ok, xlnt, a decision. you may very well find that you wont want to do anything else after this so as i mentioned, you might want to just try the gears before making any other changes.

also, if you ever go to slightly larger diameter tires, you wont loose all the power you gained like you would if you used 3.00 gears than went to a taller tire.

  Sorry I like to study and consider options.

[GEOFF289]

Mark, I presume you went through the procedure I outlined (might have been in a different thread I think) and verified that you do have 2.80 diff at the moment?

[mcarnage59]

Mark, I presume you went through the procedure I outlined (might have been in a different thread I think) and verified that you do have 2.80 diff at the moment?

Yes I did Geoff, thank you for the lesson. I had the car in the air doing another job and took the opportuity to confirm 2.8. That's one job I could manage without a blow by blow from Barnett