'84 5.0 CFI-to-carb smog-legal conversion?

Darkwriter77

Darkwriter77

Resident Ranting Negative Nancy
5 Year Member
Jul 1, 2005
314
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Apache Junction, AZ
#1
Been looking at an '84 5.0 LX hatch with CFI that I might be obtaining soon, but thought I'd ask to know what I'm getting into before I wind up getting it and finding out I can't do jack with it. I know the basics involved in what's needed to actually do the conversion - Duraspark ignition swap, delete the frame fuel pump, AOD linkage to the carb, etc. - but as far as being able to pass smog ... if I put the CFI-to-carb swap together with 50-state legal bits (intake and carb, mainly), and since they did still have carb'ed 5.0's in '84, would I still be able to pass Arizona smog testing?

Visually, I don't think they'd have a gripe as long as the EGR and smog pump connections are all there, but will the actual emissions be worse than with the CFI setup?

Just the same ... would it even be worth messing with swapping from CFI to carb? ... Or can decent power (around 200 rwhp) still be made on a CFI setup? :shrug:

I know that swapping to EFI would be the obvious better upgrade (especially just dropping in a whole '87-'93 long block), but it's a LOT more involved (and expensive) than swapping to a carbed deal. Not looking to crank out 300+ horses or anything wild, just something simple and cheap to put together, running well, and not having any smog inspection issues.
 
#4
That's just it, though - the conversion from CFI isn't just a matter of slapping on a carb and matching intake, the ignition and fuel delibery system is different, as well. And the ignition system has to be a stand-alone deal, since it won't be using the ECM, so presumably I'd have to use something from the non-computer years (late 70's Mustang II's, for example) ... ummm, right? :scratch: Or at least something designed aftermarket to fit those older applications.

Anyone know of a specific commonly-used combo to replace the CFI setup? Such as an Edelbrock Performer intake with 600cfm carb, with a late-70's Duraspark ignition? Obviously, I wouldn't be making any better power if I just swapped the stock carbed stuff from '79 to '84 on there (or would I?), so I'm trying to figure what would work for an '84 and still be smog-legal ... if anything. :shrug:
 
#5
When we converted my friend's 84.5 GT350 CFI. We took a carbed setup from a 85 GT. We took the dizzy, the duraspark, intake and all the smog hoses and what not. Carbed cars are not computer cars. We left the electric fuel pump and used a regulator to keep it at 6 pounds. I dont know how he made it work but it did. As for the linkage he just used the what was on the car. He ran it until he sold the car back in 01 and it passed all California Smog insprctions.
 
#6
CFI in 84 was Calif only so that should't be an emmisions issue outside of Calif. Check with Summit or Jegs for smog legal equipment and then buy either from them or used if you want. I'd buy the carb new so you don't buy something with problems. 600 cfm would be a good choice and improve performance. Another good upgrade for your 84 would be dual exaust either from a later model Mustang or the aftermarket. Get rid of the 84 factory cast iron exaust manifolds if they are still on the car and you will need the 85 or later transmission crossmember to clear the duals.
 
#7
93 LX said:
When we converted my friend's 84.5 GT350 CFI. We took a carbed setup from a 85 GT. We took the dizzy, the duraspark, intake and all the smog hoses and what not. Carbed cars are not computer cars. We left the electric fuel pump and used a regulator to keep it at 6 pounds. I dont know how he made it work but it did. As for the linkage he just used the what was on the car. He ran it until he sold the car back in 01 and it passed all California Smog insprctions.
Click to expand...

GaryB said:
CFI in 84 was Calif only so that should't be an emmisions issue outside of Calif. Check with Summit or Jegs for smog legal equipment and then buy either from them or used if you want. I'd buy the carb new so you don't buy something with problems. 600 cfm would be a good choice and improve performance. Another good upgrade for your 84 would be dual exaust either from a later model Mustang or the aftermarket. Get rid of the 84 factory cast iron exaust manifolds if they are still on the car and you will need the 85 or later transmission crossmember to clear the duals.
Click to expand...

Schweeeeet. That's what I was needin' to know. Thanks! :nice:
 
#8
Just outta curiosity ... how much of an increase should I expect to get in doing this CFI-to-carb conversion, using aftermarket parts (probably a 600cfm Edelbrock or Holley, and a smog-legal intake) and updating the exhaust to an '87+ setup with an off-road X-pipe? Maybe ... what, 25 horses at best? :shrug:
 
#11
Well considering the engine with CFI is under 200 hps I would say anything you do is going to help. You biggest obstical is going to be the heads. Getting the fuel in and exhaust of the heads is where you will get the biggest bang for your buck. I am not sure if this will work but if you get hold of a set of E7, 1987 and later HO heads, you will be better off however you have flat top pistons so this may not be advisable.
 
#12
As I understand it, I can't use E7 heads on an '84 block because in '85 they became roller motors, so it wouldn't be compatible without adding an expensive roller conversion kit. I would like to throw on some different heads and perhaps a cam later on, but I dunno what I would use for something like that ... probably something from a 302 of the late 60's/early 70's, I would assume...? (Or some 289 heads?) :scratch: I know the heads will be a major bottleneck, and probably the cam, as well. I dunno for sure if the pistons are flat-tops or not, but valve clearance issues and such are something I won't have to worry about until I go swapping heads and/or cam later, anyway.

I guess what more specifically I should ask is, what's the most power one can expect to get out of a set of stock '84 heads (with a stock cam)? :shrug:

Again, I'd be keeping the stock cam and heads, but bolting on an aftermarket intake, carb, and exhaust. I know that the exhaust is VERY restrictive on its current single-exit setup, which looks like it was meant more for a V6 than anything. If I can get another 25 horses out of it from a carb/intake/exhaust upgrade, then I'll be content for awhile ... until I get into a position where I can afford a place with a garage, whereupon I'll likely swap out the whole long block with an '87-'93 H.O. motor, or better. :)
 
#13
Not sure you fully understand the head swap issue. E7s on older blocks works well. Its got nothing to do with the cam, its more to do with the flat top pistons in 82-86 HO engines. 87 and above have valve eye brows.

Now on to the power issues at hand. Here is a quote from the site: http://www.edmunds.com/insideline/do/Features/articleId=93320

The drivetrain lineup was also revised for '83 with the straight six and 4.2-liter V8 being eliminated and quickly forgotten. A revised version of the turbocharged 2.3-liter SOHC four returned to the lineup, this time with electronic fuel injection that did a wonderful job of tempering turbo lag and increasing engine longevity. But its 142-horsepower output didn't seem all that impressive, especially since the 5.0-liter HO V8 now sported a four-barrel carburetor and was rated at 175 horsepower. And the V8 was now available with the excellent Borg-Warner T5 five-speed manual transmission.

Much of the 1984 Mustang line was carried over from '83, but there were a few changes and an unexpected new model in the line. Although there was supposed to be a more powerful (205 hp) 5.0 V8 this year, development problems killed it. A fuel-injected version of the HO V8 with 165 hp was offered with the automatic transmission (now with a fourth overdrive gear). The turbo four was back for one last year, now rated at 145 horsepower in the Mustang GT.
 
#14
I'm already aware of what the CFI motors make in stock form. I'm just curious what gain (if any) there would be in swapping out the stock CFI and exhaust in favor of an aftermarket carb, intake, and full exhaust.

So, you're saying you can just slap a set of E7's on a non-roller block? Ummm ... how? :scratch: The '85+ 302's were roller motors, and the older blocks used solid lifters, no? So, short of blowing a chunk o' change on a roller conversion kit to make the E7's work on the block, or just swapping the whole long block out completely, I would need older-style heads if I'm keeping the stock '84 block. Ummm ... correct? :shrug:
 
#15
Darkwriter77 said:
I'm already aware of what the CFI motors make in stock form. I'm just curious what gain (if any) there would be in swapping out the stock CFI and exhaust in favor of an aftermarket carb, intake, and full exhaust.
Click to expand...


Exhaust and carb may be worth 50 hps at the max.

Darkwriter77 said:
So, you're saying you can just slap a set of E7's on a non-roller block? Ummm ... how? :scratch: The '85+ 302's were roller motors, and the older blocks used solid lifters, no? So, short of blowing a chunk o' change on a roller conversion kit to make the E7's work on the block, or just swapping the whole long block out completely, I would need older-style heads if I'm keeping the stock '84 block. Ummm ... correct? :shrug:
Click to expand...

I am not sure why you think the cam has anything to do with the heads. Since E7 heads came out in 87 what did they use on 85 and 86 engines? I have installed ported E7s on a 82 GT with out any issues other then having to fly cut eyebrows in the pistons to allow the use of the Comp Cam we installed.
 
#16
93 LX said:
Exhaust and carb may be worth 50 hps at the max.



I am not sure why you think the cam has anything to do with the heads. Since E7 heads came out in 87 what did they use on 85 and 86 engines? I have installed ported E7s on a 82 GT with out any issues other then having to fly cut eyebrows in the pistons to allow the use of the Comp Cam we installed.
Click to expand...

I was just always under the impression that E7's couldn't simply be thrown on a non-roller block because of valve-to-piston clearance issues, which is related to the difference in cams between roller and non-roller blocks. I would have to change out more stuff than it would even be worth doing on an '84 block, which isn't as strong as an '87+ and has crappy pistons to begin with. If I stick with older heads that flow better (if there are any), then I could get by with a cheaper swap that I could do in my driveway, as opposed to simply swapping the entire long block assembly.

But ... anyhow. That aside, 50 horses from a carb conversion and full exhaust sounds good enough to me to warrant doing it. I was expecting something a lot smaller like 25. :nice:
 
#17
Darkwriter77 said:
I was just always under the impression that E7's couldn't simply be thrown on a non-roller block because of valve-to-piston clearance issues, which is related to the difference in cams between roller and non-roller blocks. I would have to change out more stuff than it would even be worth doing on an '84 block, which isn't as strong as an '87+ and has crappy pistons to begin with. If I stick with older heads that flow better (if there are any), then I could get by with a cheaper swap that I could do in my driveway, as opposed to simply swapping the entire long block assembly.
Click to expand...


All 5.0L HO block are weak. There are things to help strengthen it but all in all they wont see too many days at 500hps.

You are right there is a piston/valve clearence issues with those heads on older blocks. Most of it is related to the pistons used in the older non-roller and up to 86 roller blocks. thats why you fly cut the pistons in most cases. Falt top pistons in older blocks, newer ones have valve eyebrows....
 
#18
Resurrecting this thread from its comatose state. :D

Okay, so from what I gather, I need to obtain the following for the conversion:

1. Duraspark or other stand-alone distributor
2. Carb (leaning towards an Edelbrock 600cfm)
3. Intake (probably an Edelbrock Performer)
4. Lokar AOD cable and/or linkage bracket
5. Fuel pressure regulator w/bypass or return



Now, more questions:

1. Can anyone recommend a specific distributor (year/model) that would be the easiest plug-and-go kind of deal? I've also been considering using an old points dizzy and dropping in an electronic conversion, or going with some kind of a GM-style HEI setup, but didn't know if that'd be more of a pain/cost than it's worth, or if the old-school dizzies even work that well;

2. Should I get a carb with an electric or manual choke?

3. Does the Edelbrock Performer (the smog-legal version) use the stock EGR valve, or do I need to get a specific one to bolt onto it?

4. Will I be able to use my stock AOD TV table and hook it to the carb with a Lokar adapter, or do I need a whole new cable?

5. Any particular brand/type I should be looking for? There's a Spectre/Mr. Gasket brand regulator available at Autozone for cheap that looks like it'd do the job... :shrug:
 
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