update on 5 speed/306 swap! pics of trans!

[sly]

I've seen those same MPG numbers with 600CFM carbs too. YMMV

[1987cp]

That's about 250cfm too much for that motor.

Says who? I'm learning to go by what people report actually experiencing in the real world with a well-thought-out overall combination, not a formula that applies more to the days of iron exhaust logs and stone-age cam grinds. The line of thought I've been reading about for the past year or two is to give your engine as much airflow capacity as you can (given your budget, race rules, government inspection goons, etc.), and then select or design a cam that makes your engine do what you need in the desired RPM range. If using a carb, you select one with good response characteristics, possibly a modern annular-booster design, and use a cam grind with a good intake vacuum signal.

Incidentally, my better 5.0L is quite noticably more responsive with my 600cfm base on the AFB instead of the 500cfm that the formulas prescribe. I also have better low-end response with a divided single plane intake than with a Performer 2121 dual plane. And that's using a cam designed for SEFI, which may or may not have a particularly good intake signal, working with a carb design first intruduced 54 years ago!


(BTW ... IIRC, the carb formulas I've seen seem to suggest that even a 400cfm carb is adequate for a 302ci engine.)

[1990LTD]

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http://sbftech.com/index.php/topic,8087.0.html

[1987cp]

That's in the Myths and Rumors forum, gotta be a member with at least 10 posts to view it.

But the short of it is simply that "too big" often isn't. And of course, there will always be those folks who are perfectly intelligent but still refuse to believe that viewpoint.

[86VickyLX]

Ew, is that a V6 explorer? I hope that's not the original engine, or if it is, it has the updated timing chain tensioners/guides.

[sly]

That's in the Myths and Rumors forum, gotta be a member with at least 10 posts to view it.

But the short of it is simply that "too big" often isn't. And of course, there will always be those folks who are perfectly intelligent but still refuse to believe that viewpoint.

a well tuned carb that is twice as much as an engine needs or can even use will still work well since the air flow through it is limited by the engine's ability to move the air. now getting off idle flooding taken care of in a situation like that can be tricky... which is why you don't want to go too big.

[Nick52284]

yea its a sohc 4.0, this things starts strong and has a nice smooth idle, no weird noises, oil looked clean trans fluid is a little brown but it doesn't smell burnt, as long as it lasts me through winter i'll prolly sell it

[Pesty351]

Speaking of clutch pedals...
You need to swap to the later style brake booster AND master cylinder. (88+)
Your 86 stuff will not work...

His master cylinder will bolt up to the newer style brake booster and you need a 92+ booster.

[GoodSamaritan]

I had 4bbl sound, then I upgraded to EFI power, economy, cleanliness, and refinement. My 4bbl was tuned good and ran smooth, but EFI is still better. Quit talking to hillbillies and circle track junkies about how to mod your car.

There are three main reasons for 99% of the complaints with carbs.

#1 Smog era carbs, that were overcomplicated, and or tuned to please the epa.

#2 Poorly maintained, adjusted worn out carbs that fell into category #1 even when they were new.

#3 People who can't seem to tune carbs properly.



I do admit that a properly working EFI is more efficient, and often smoother. *

Carbs, when properly tuned, are:

Less work
are much more tolerant of cam/head/etc changes.
much cleaner install
have fewer failure points
best of all, they are a LOT cheaper.

















*There's still nothing quite like the sound of the secondaries howling on a V8 with a 4bbl carb.

[Crownvicman289]

Carbs, when properly tuned, are:

Less work
are much more tolerant of cam/head/etc changes.
much cleaner install
have fewer failure points
best of all, they are a LOT cheaper.

*There's still nothing quite like the sound of the secondaries howling on a V8 with a 4bbl carb.

Totally gonna have to disagree on a few points here. When you change heads and cam, you change jets on a carb. Well EFI needs a retune too, then it's 100% tolerant of cam/head/etc changes. Problem is, nobody ever does it then bitches when their junk runs like shit, just like the idiots that can't properly tune their carbs. Much cleaner install, gonna give you that one hands down. Fewer failure points. . . modern EFI has fewer moving parts than ever. Even so, the archaic EEC-IV is usually capable of telling you what's wrong. There's not much to go wrong, if you're apt enough to ohm out a few sensors to verify they're in tolerance and do the KOEO and KOER tests, you can eliminate 99% of what it's not. Most people don't know how to properly troubleshoot, which is also a problem if you're attempting to fix a carb'd vehicle. Totally gonna argue the cheaper part too. Last I checked a quarter horse is about $300, cheaper than a carb and intake off of Summit and you'd still need an FPR. Both can be had cheaper used, so again a moot point. It's all in what you want, I get so sick and tired of people dogging EFI saying that it's too complicated and won't tolerate mods because it's just not true. It's also not that complicated! Like somebody said above, this isn't the 60s anymore so move on already!

[86VickyLX]

His master cylinder will bolt up to the newer style brake booster and you need a 92+ booster.

I have the original 86 master cylinder on my car. And it DOES NOT bolt up to my 93 brake booster! It will not bolt up to his either.

[packman]

I think it's how you're raised and who you're raised with. I only know classic American cars. We're too poor to get anything new. Up until we got the CV (which btw, is and has been a classic for some time now), we were dealing with carbs. If you know how to tune a carb, then you will prefer taking tiny screw drivers and messing with the idle mixture screws and taking the carb apart to tune it. If you grew up around EFI, then you will be more of an electrician as Crownvicman289 said. I have been begrudgingly converted to EFI. EFI is 25 years old and at some point, I will have to learn. A lot of people don't even know what a carb is anymore!



Packman

[Pesty351]

My 84 MC bolted to a 94 booster.

[GoodSamaritan]

Totally gonna have to disagree on a few points here. When you change heads and cam, you change jets on a carb. Well EFI needs a retune too, then it's 100% tolerant of cam/head/etc changes. Problem is, nobody ever does it then bitches when their junk runs like shit, just like the idiots that can't properly tune their carbs.then it's 100% tolerant of cam/head/etc changes. Problem is, nobody ever does it then bitches when their junk runs like shit, just like the idiots that can't properly tune their carbs.

Well it all depends on how much of a change you make. A 600cfm carb will run pretty well on a mild, low displacement v8 (lo-po 302) all the way up to a 393 stroker, with the stock jets. Granted the 393, is going to be starving for fuel on the upper end, but it will still work ok as a daily driver until you can get around to it.

Much cleaner install, gonna give you that one hands down.

No argument there. I would like to point out that if the carb has more than 2 or 3 vacuum lines going to it, it's probably an emissions carb and should be relegated to door stop duty.

Fewer failure points. . . modern EFI has fewer moving parts than ever. Even so, the archaic EEC-IV is usually capable of telling you what's wrong. There's not much to go wrong, if you're apt enough to ohm out a few sensors to verify they're in tolerance and do the KOEO and KOER tests, you can eliminate 99% of what it's not. Most people don't know how to properly troubleshoot, which is also a problem if you're attempting to fix a carb'd vehicle.

Sometimes it isn't about moving parts as it is about intermittent sensors, connections, etc. When you consider that nearly every ground, connection, wire, solenoid, sensor, injector, etc, etc, even the ecm, are potential failure points, I stand by my original statement. As for troubleshooting, I'm going to point out that I started out in industrial electronics. I've custom built the controls and wiring harnesses for cnc machines that were 28 feet wide, and had 72 toggle switches and 18+ push buttons and 82 relays in the manual override section alone. I've worked with plc's, relays and pretty much every sort of transducer (scalable and otherwise) used in industrial applications up until 10 years ago. Troubleshooting is second nature to me and I've been working on cars for over 20 years.

Having said that, I still prefer the simplicity, and reliability of a well tuned carb.

Totally gonna argue the cheaper part too. Last I checked a quarter horse is about $300, cheaper than a carb and intake off of Summit and you'd still need an FPR. Both can be had cheaper used, so again a moot point.

If you grab a used intake for 50-75$ off cl, and then buy a new carb on sale from summit for 230-275$ that's pretty dang cheap.
Granted I'll give you the price being similar, when you get used parts. But let's look at replacement parts.

CARB - My local autozone has a complete rebuild kit on the shelf for an edelbrock 1406 (i keep using that as an example, because i am familiar with it) for around 45$ Summit or Jegs usually have that sort of stuff a tad cheaper. That will take care of pretty much anything that will get out of whack short of physically wearing out the shaft, or linkage.

EFI -After a brief search on autozone for the cheapest common crap they sell for my 89 wagon, here's what I've found.

MAP sensor $39.99
O2 sensor $39.99 each
Tps $32.99

It's all in what you want, I get so sick and tired of people dogging EFI saying that it's too complicated and won't tolerate mods because it's just not true. It's also not that complicated! Like somebody said above, this isn't the 60s anymore so move on already!

I get sick and tired of EFI guys looking down their noses at carbs and portraying them as stone age technology, only used by people too stupid to understand EFI. Let me tell you, I've run more cable, and troubleshot/built more control systems than anyone on this site that I'm aware of.
At the end of the day, I still prefer a carb on most of my project vehicles.
As for it not being the 1960's, just because a technology is old, doesn't make it worthless.

I'll give you an example. I have a really really REALLY tough beard. The latest super duper high dollar razors only last me one shave before starting to pull terribly. No matter how careful I was I constantly got razor burn on my neck.
At $25+ a box of cartridges it was getting expensive too. I was mentioning this to a friend one day when an old guy walks up and suggests I try an old double edge razor. You know, the kind your grandpa might have had in the medicine cabinet, where you open it up and drop in a razor blade. This was about the same time we were cleaning out my grandparents house, and I found my grandpa's 1948 Gillette Super Speed razor. I picked up a 10 pack of blades for $1 and change. WOW. I had to stop a time or two and double check my face to make sure it was actually cutting my beard. It was the first shave of my adult life that didn't hurt. After a little more research, I discovered I can get a week on 1 blade. That and I can buy a box of 100 blades online for 15$ That's two years of shaving for 15$ with no razor burn, vs uncomfortable expensive shaves.
I've never looked back.

Now for 99% of guys the new stuff works great. You don't have to pay as much attention to what you're doing so you don't nick yourself. But the old tech isn't totally obsolete just because it's been superseded by something new.

[sly]

But the old tech isn't totally obsolete just because it's been superseded by something new.

+1

I can diagnose my car with a wire and multimeter. new cars you gotta have diagnostic readers (scan tools) to get much of anywhere with them usually. of course... all of mine are EFI, but not the new overtly electronic models. Carbs are even easier to diagnose... flap the choke back and forth and you can usually figure out what the issue is (or just check for vacuum leaks).

I prefer the older cars... mainly cause they're cheaper to run for total financial burden. You can run a LOT of gas through a gas hog for what you pay for new(er) cars these days.