c4 injection to carb

[mfawcett]

Hello
I am new to the corvette group and have a few ?
I just picked up a 84 vette that was converted to a carb and it has no air filter on it and it don't look like one will fit. What are all you guys using on your carbs is there a special air cleaner or do I have to put a hood scoop on to have one fit?
Thanks Mike

[DannyC4]

Hello, I also have an 84, and I was just wondering, are you gonna be able to pass the emissions inspection/test with the carb setup? Do you still have the smog pump and the cat and everything else? Because Im ready to start modifing my vette, and that is one of my options. How does it work by the way? Is it too hard to start it up in the morning when its cold? Any problems you have noticed so far? Thanks!!! I think I saw a low rise air cleaner on one of my catalogs that I have, Im gonna look and then Ill let you know. Good luck!!!

[mfawcett]

Dannyc4
How you doin
I just picked the car up yesterday and don't know to much about it as for emmissions it should pass with a carb as long as its tunned and if it don't you just tweek it leaner or richer to adjust your hc, co2, etc...
I haven't checked the cats yet to see if they took them off or not the first thing I did was take off the junk holley carb because it ws trash and put on a edelbrock 600 cfm #1406 with auto choke. I know the smog pump is unhooked so we have to see what happens there. My son has a 87 monte carlo ss and and all the emissions are unhooked and carb changed and it passed. the only thing I see is the air filter is going to give me trouble right now. I will let you know what I come up with
MIke

[TEXAS-HOTROD]

Usually when you modify a Vette, you decrease the value of the car by the amount that you put into it.
Doing a hack-job is really uncool. If you want to score some points, put a TPI in place of the Cross-Fire set up. I always thought the C-F systems looked good. It's a retro system that you hardly ever see, and the ones that I drove ran really good considering what they were.

[DannyC4]

Do you think the digital dash would work the same, or would work at all if you swap the L-83 for an L-98, or even better, an LT-1? All the functions that it has, I think its pretty cool, all of my friends like it. I aggree with "TEXAS-HOTROD", I would like to either upgrade the CFI, or get a better FI system, I dont really like the idea of going from FI to Carb, but that is still an option. Thanks!

[TEXAS-HOTROD]

I guess I have just seen too many cheezy conversions where people remove a perfectly good e.f.i. system and rig it up w/a carb. Then it ends up in my shop because it won't run and it has all kinds of problems. It's not worth the hassle. Besides, there's no room for an air cleaner housing anyway.

I would think that the dash works off of the tach signal from the distributor, but I'd have to check the schematic to be sure. TBI and TPI both use the same distributor, so to swap from one to the other is pretty simple. LT1 is a whole different ball game. The LT1 is a good system, but LT1 is LT1, nothing else will interchange. Edelbrock makes an intake for the LT1 and w/the oil pump drive unit removed, you can install a conventional HEI and have a good hot-rod motor. Then you're back to square 1 w/the carb situtation.
I think I read an article somewhere where the LT1 intake was bored out to accept a small diameter (late model) HEI distributor (there's no room for the large unit) and it was installed into an earlier Camaro. So w/some fabricating and engineering it can work. Use the LT1 engine assembly, retrofit the later HEI distributor (if possible) and wire it to a TPI e.c.m. Have to swap throttle sensors, or install the correct pig-tail to fit the newer style sensor (the ignition modules are different too). It should work. The factory TPI air snorkel should work too.

I have all the necessary parts to build a 406. I have A.F.R. aluminum heads, a nice set of rods and a stock, standard 400 short block. All I need is pistons and machine work. If the stock Vette motor ever gets tired, I'll keep it complete, store it on a stand and swap in the other one.
I have a Victor Jr. intake drilled for fuel injectors, all I need to do is make an adapter to connect the throttle body and the air snorkel and fab up a fuel rail. The TPI is a great system, but it does have limits and is restrictive when pushing bigger cubes. The Victor Jr. flows well and keeping the electronics will make for great driveability.

Anything is possible. it just depends on your limitations and how much you want to spend. Having great performance makes the hassle worth it.

[corvettemike5984]

i own a 84 corvette as well as 78 and 59 corvette. ive modified all 3 to my liking, the 84 ive had for 20 years, it was red cfi with 4+3 tranny, to make it better change to carb, remove ecm fuse from fuse panel ,disconnect ecm in pasenger lower dash, snip injector wires 1 and 2 behind fuse pane,l if you like. cut wires to cfi off in engine bay .rewrap wires with electrical tape and plastic conduit so they look good, you can reuse throttle cable, use eldebrock torqur or performer intake,use a nut and loger bolt to mount cable bracket , to bring it up to corect height ,cable will be a little long: so what, i took cruise control off, i can interchanged holley or elderbrock carb with no changes this is on a 4 3 tranny mind you .700r4 is about the same ,only other thing using same serpenting setup you will have to use 2 washers on hole in front of intake to mount pollution pump on 84s not sure about latter ones, if you have the 4+3 transmission remove the center console piece. run a red 18 guage wire from the from the switch where it plugs in. to a ignition activated hot wire or to the back of the fuse panel thats is energized when you turn on the key . run a holley fuel pressure regulator, mount it to the valve cover since you are using the electric pump in the tank ,no other room i could find to put it, any low profile breather will work, i have k&n etreme lid and breather if you want to drop a 383 355 who can afford fi ,i have a 650 double pumber with choke horn cut off on mine, 22mpg hyway , remember, put a good carb on it ,the hood will close with low rise intake . the 4+ 3 is great: overdrive in all 4 gears, no ecm to get in your way just treat it well and change the fluid often and make sure your radiater is not full of rust and you have new fan and car will never overheat if it does change tranny fluid and check gear oil oh yea insulate door panels and console buy some new tires and the car rides like a cadilac except over the rougfest roads even z51 equipped cars, its bs its always been the tires and insulation that gave these cars a bad wrap, try g force sports and you will say i cant believe the difference dont run down 84s there awsome new vettes have newer tires, gatorback and older tires ride harable and earlier c4s need insulation and the ride will be queiter and newer tires and the car do this if your a good machanic if your not leave it alone buy a latter model there not perfect either but maybe for you if you have a 700r4 buy a 4th gear lock up torque converter switch install you might be able to run a new wire from ignition to switch on tranny to activate lockup in 2nd 3rd and 4th because its already there ecm is now disconnected just needs power not sure havent done it if dont know how buy the kits its not hard about 80 bucks because the ecm activated lock up on 700s just like it activated those solinoids on the 4+3 i put a lock up kit in my 59s 700r4 for 4thgear it wasnt hard had to read directions 5 times but thats another mod that made that 59 corvette highway roadable 2200 at 70 375 gear thats another story thanks

[Schrade]

Originally Posted by corvettemike5984

i own a 84 corvette as well as 78 and 59 corvette. ive modified all 3 to my liking, the 84 ive had for 20 years, it was red cfi with 4+3 tranny, to make it better change to carb, remove ecm fuse from fuse panel ,disconnect ecm in pasenger lower dash, snip injector wires 1 and 2 behind fuse pane,l if you like. cut wires to cfi off in engine bay .rewrap wires with electrical tape and plastic conduit so they look good, you can reuse throttle cable, use eldebrock torqur or performer intake,use a nut and loger bolt to mount cable bracket , to bring it up to corect height ,cable will be a little long: so what, i took cruise control off, i can interchanged holley or elderbrock carb with no changes this is on a 4 3 tranny mind you .700r4 is about the same ,only other thing using same serpenting setup you will have to use 2 washers on hole in front of intake to mount pollution pump on 84s not sure about latter ones, if you have the 4+3 transmission remove the center console piece. run a red 18 guage wire from the from the switch where it plugs in. to a ignition activated hot wire or to the back of the fuse panel thats is energized when you turn on the key . run a holley fuel pressure regulator, mount it to the valve cover since you are using the electric pump in the tank ,no other room i could find to put it, any low profile breather will work, i have k&n etreme lid and breather if you want to drop a 383 355 who can afford fi ,i have a 650 double pumber with choke horn cut off on mine, 22mpg hyway , remember, put a good carb on it ,the hood will close with low rise intake . the 4+ 3 is great: overdrive in all 4 gears, no ecm to get in your way just treat it well and change the fluid often and make sure your radiater is not full of rust and you have new fan and car will never overheat if it does change tranny fluid and check gear oil oh yea insulate door panels and console buy some new tires and the car rides like a cadilac except over the rougfest roads even z51 equipped cars, its bs its always been the tires and insulation that gave these cars a bad wrap, try g force sports and you will say i cant believe the difference dont run down 84s there awsome new vettes have newer tires, gatorback and older tires ride harable and earlier c4s need insulation and the ride will be queiter and newer tires and the car do this if your a good machanic if your not leave it alone buy a latter model there not perfect either but maybe for you if you have a 700r4 buy a 4th gear lock up torque converter switch install you might be able to run a new wire from ignition to switch on tranny to activate lockup in 2nd 3rd and 4th because its already there ecm is now disconnected just needs power not sure havent done it if dont know how buy the kits its not hard about 80 bucks because the ecm activated lock up on 700s just like it activated those solinoids on the 4+3 i put a lock up kit in my 59s 700r4 for 4thgear it wasnt hard had to read directions 5 times but thats another mod that made that 59 corvette highway roadable 2200 at 70 375 gear thats another story thanks

Your post is more BS than I can fit in my garden. I doubt your dad even owns 3 vettes - someone like that would disown a child that writes like you do.

[Blue Bowtie]

I'd vote for a TPI conversion, with a possibility of future upgrade to Stealth Ram (LT1 clone). The CFI systems are somewhat limiting, but the car is probably more valuable with it over a carb. Most people looking wouldn't know a TPI didn't belong there, but a true enthusiast would. The CFI fuel pump in an '84 is very easy to change to a higher pressure variant for TPI. The rest is mostly bolting and wiring.

[batvette]

Lotsa good info here, a little BS too.

1. Any vette including 84's is best left alone if for an investment. If you're driving it though GM had deficiencies in every year, as '84s were all new EXCEPT for the engine which was as good as straight carried over from '82 that is the most glaring.

2. '84's are perfectly good cars, it's true they are bashed often unfairly but that's because in just a year or two GM tinkered with the faults and the result was a much more drivable car that was truly world class by '86. The '86 was the fastest, quickest, best handling automobile available for sale in the US in 1986 per car and driver or MT or R & T (whichever one it was that published the often referenced head to head test including the outclassed Supra, Porsche 944, and Ferrari 328 competition) Top speed was 158, best in world braking and skidpad. I think the only catagory it came 2nd in was the 944 edged it in the slalom.

Inidentally the mid-production 86 with iron heads came from the factory running probably 10% more power than the recalled (at the time) aluminum heads and possibly 15% more than '85's iron heads. This is well referenced in the media at the time, always saying "apparantly in phenomenal tune" with test vehicles off the showroom clocking 0-60 in the mid to high fives.
For this reason I sought an iron head 86 back in 87 and still own it. My uninformed speculation would be that upon rampant reports of cracking aluminum heads and halting production immediately, they refitted the blocks with iron heads with specifications from the previous year but as the blocks were set up for aluminum heads(with larger combustion chamber) the compression ratios were far higher than they would normally shoot for. What leads me to say this is would be how sensitive these models are to octane levels and cheap gas in general. Forget ARCO, fill it with that and the car would actually not restart when the good fuel purged in a mile or two.
Also when aluminum head production continued sometime mid to late year you can bet GM didn't want a repeat of the cracking heads nightmare and probably had some detuning in the ECM dept, I looked into these issues extensively at the time and every indication was that an iron head 86 had significantly better performance than any other 85, 86, and was as fast or faster than even the 87 when they supposedly had all the bugs in the heads fixed.

My opinion of course.

3. any stock TPI vette can realize 10-20% power increases with minor mods. See Mid America Corvette.
The throttle body airfoil is iffy. I have one, don't know what it added.
Minor exhaust mods are good, a SS y pipe is a no brainer. HOWEVER too little back pressure in an otherwise stock TPI engine will cause no horsepower gains and may even lose a little.
Chipping is good though you might see the same gains with the following:
moving the MAT sensor to the air cleaner and getting the more sensitive version MAC sells.
Add the aux cooling fans and do the fix MAC offers to turn them on at a lower temp.

But here is your $5 best performance gain in the TPI arena: Pull the connector off the A/C head high pressure switch, and run a 2 conductor wire to a switch under the dash. Leave it turned on most of the time, in tells the ECM to run the cooling fan at all times when the car is below 40 mph and above 160 degrees f.
A new fan motor is $35 should you burn it up, which is offset by now not having to replace the engine wiring harness every 7 years. (and many plastic parts constantly damaged by GM's spec'd engine op temp at 217)

4. Schrade you are correct there was more silliness in that post than could be lampooned in one thread but I would beg to differ about your questioning he'd ever owned one.

I think his standards in many areas in life (modifying his rides and mastery of the english language for starters) are a bit below the norm. Give him a break and don't stifle his desire to share with the group. Sometimes the most brilliant revelations in engineering come from the guy pushing the broom when the degreed professionals go home and he thinks outside their box.

[JohnBoy02]

Hi, just thought to add my motor to your forum. I have an 86 C4 which I bought stripped out (a rolling chassis). It now has a 358 sbc with a 750 vac holley and a glide on the back. Also, I have fitted a 68 Camaro 10 bolt with a 4.1 spool 4 link and panhard rod with coil overs.
Question is, when fitting the carb, was the motor tilted or was the intake levelled. My HEI looks pretty close to the bulkhead due to the slight tilt. I have used C3 mounts and made my own gearbox x-member.

[batvette]

Originally Posted by JohnBoy02

Hi, just thought to add my motor to your forum. I have an 86 C4 which I bought stripped out (a rolling chassis). It now has a 358 sbc with a 750 vac holley and a glide on the back. Also, I have fitted a 68 Camaro 10 bolt with a 4.1 spool 4 link and panhard rod with coil overs.
Question is, when fitting the carb, was the motor tilted or was the intake levelled. My HEI looks pretty close to the bulkhead due to the slight tilt. I have used C3 mounts and made my own gearbox x-member.

Overall your engine should sit quite level with the rest of the chassis, there is no discernable rearward lean in respect with the rest of the vehicle. The HEI will sit pretty close to the firewall, about the thickness of your hand or less. The serpentine belt pulley on the crank in relation to the steering rack is another indicator of where it fits pretty tight. Also the factory alternator bracket just barely clears the hood when closed (I competed in IASCA audio contests and installed a large case 200a custom GM alternator, which is how I discovered how tight a fit that part of the engine is under the hood.)

I think you are finding out just how tight of a fit GM made these things. If you need I would be happy to provide an exact measurement of a critical area if it helps, say the HEI's baseplate to firewall, etc- but the overall thing is that engine doesn't tilt back and I doubt you'll get the hood closed until you get the engine's attitude straight and level.

[batvette]

Originally Posted by JohnBoy02

Hi, just thought to add my motor to your forum. I have an 86 C4 which I bought stripped out (a rolling chassis). It now has a 358 sbc with a 750 vac holley and a glide on the back. Also, I have fitted a 68 Camaro 10 bolt with a 4.1 spool 4 link and panhard rod with coil overs.
Question is, when fitting the carb, was the motor tilted or was the intake levelled. My HEI looks pretty close to the bulkhead due to the slight tilt. I have used C3 mounts and made my own gearbox x-member.

I might add you might want to start looking around locally in junkyards etc for a TPI setup. When you do get it running you'll likely find the carb frustrating and performance is going to be hindered by any intake setup you can get under that hood.
It's widely acknowledged that the Tuned Port Injection intake was one of GM's really shining moments in engineering, they are plentiful and are very adaptable to upgrades for reasonably high hp engines.

[JohnBoy02]

I am building it more as a hotrod not a restoration so it has become more of an ebay special. Feel free to browse and comment. With cam and head mods it should be more like a 358/358 plus 100 nos. http://s12.photobucket.com/albums/a2...cpZZ1QQtppZZ20

[batvette]

Originally Posted by JohnBoy02

I am building it more as a hotrod not a restoration so it has become more of an ebay special. Feel free to browse and comment. With cam and head mods it should be more like a 358/358 plus 100 nos. http://s12.photobucket.com/albums/a2...cpZZ1QQtppZZ20

Ah, we can just forget about that 3 counties off the mark comment I made about getting the hood closed! Looks like it will be fast.
My first impression (probably motivated by my now 48 yo back which screams after 10 minutes of standing) is "damn that looks like a lot of work" but so was mine I guess when I started on all this stuff:

http://s353.photobucket.com/albums/r...vette%20IASCA/

yeah I still own the car, haven't driven it in about 5 years.

As an aside, it was the second car in that album that physically took a toll, working 9 hours a day, come home, eat dinner, wrench till midnight or later. Too many nights I pushed it, ignoring the pain.

It's difficult to drag out the floor jack and change the oil now. I couldn't imagine that 15 years ago. FWIW just a heads up.