votec heads on 1992 ?

[canso]

I have a 92 chev 350. I want to install a set of vortec heads. I know this is pretty straight forward job. Although I have be told that you can not install the egr valve with the vortec heads and the engine will run to lean if you just leave it off. I was also told that all you can do to correct this is to order a custom chip from somewhere. Has anyone done this convertion on a truck with throttle body injection any ideas. Thanks

[CEDJUNIOR]

Ok, the heads bolt right on, you need a special intake manifold in order to use the TBI. Most vortec TBI intakes have a place to put the egr, you just need to plumb it from the exhaust. I have seen kits for that, and you will either need to but a 96 or newer exhaust manifold or buy headers and modify them so you can plumb the egr.

[hugger67]

i have done this a few times and it is pretty easy i have the intake that you need and i am looking to sell it i can also get the egr parts or part numbers if you want let me know

andy

[superchevy]

I'm running an Edelbrock Performer carb manifold with EGR on my '93 tbi by using the $12 carb-to-tbi adapter plate to mount the tbi to the 4-barrel intake.
I have thought about putting the Vortec heads on my '93 and using the GM Performance parts Vortec carb intake with EGR - see the pics.
Wouldn't this be a whole lot easier, cheaper - and perform better - than plumbing the EGR when using the Vortec tbi intake?
Just wondering.
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[CEDJUNIOR]

The Vortec heads themselves we not made for use with the EGR the way pre-vortec head are, thats where the problem is. For pre-tbi applications vortecs are great because the egr is generally not an issue, but for tbi engines using vortecs can get kind of costly. Try using some L98 heads. They are a little more expensive that the vortecs but the cost is offset due to the L98's bolting right up with out having to buy a new intake or plumb and egr.

[superchevy]

Attached is a pic of a tbi motor (Camaro) with the GM Performance carb vortec intake and EGR plumbing off the driver's side port of the intake run to the driver's side header - no big deal to plumb.
I mean, if you're going to do this mod - Vortec heads - you might as well put headers on while you're in there - drill a hole in the header tube of your choice, and have a muffler shop weld in a bung for the EGR pipe fitting.
This install on the Camaro is a little cluttered for my liking, so I put a couple of pics of my Performer carb intake/tbi set-up on my '93 to give you an idea of how clean it would look without all that other crap on there.
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[superchevy]

pic 1 of my '93 truck tbi set-up

[superchevy]

pic 2

[racedvl]

Check out this kit.

http://www.sdpc2000.com/cart.asp?act...2173&pid=89533

[CEDJUNIOR]

How do you get away with an open filter element? Just curious, I was told my 95 wouldn't pass inspection with an open air element. The pic from that camaro looks like the owner just used headers with the A.I.R. connection on them, never thought of that. That would make the egr thing alot easier. The tough part is still having to buy that vortec intake for $300. $450 for the vortecs and $300 for the intake puts you at $750. It would be cheaper to buy the L98's, or some SR Torquers and keep your current intake/tbi setup.

[superchevy]

The open element hasn't been a problem to get inspected.
I've had it on for 2 years now.
As for the GM Performance carb intake, part# 12496820, it's only $205 at www.gmpartsdirect.com.
The crappy flowing vortec TBI intake is $300.
The vortec heads are much better flowing than the L98's. Yes, I know Lingenfelter loves the L98's, but he didn't have Vortecs to work with when he wrote his book, and he ported the crap out of the L98's.
The Vortecs are $235 each at gmpartsdirect. They're good up to .450 lift out of the box, and considering the .398 and .401 lift specs of the stock tbi cam, you could just bolt them on and go.
Of course if you want to run a little more cam, you might want to upgrade the springs.
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[CEDJUNIOR]

At some point, no matter how good the heads flow, the TBI will be a limiting factor. Sure, even with a stock throttle body, adding the vortec heads will improve perfromance over the stock TBI heads. The same can be said about adding the L98 heads and improving performance over the stock heads. But how much performance will you gain from the vortecs over the L98's while keeping the stock throttle body? If you are planning on going with a 454 throttle body or upgrading the air/fuel delivery system then vortecs are 100% the way to go I guess.

[superchevy]

You're preaching to the choir about tbi's being restrictive. It's something I've come to know well over the last couple of years.

It has been very frustrating for me an old school, grew-up-tuning-Holley's kind of guy, to spend so much money and time trying to get power out of basically a 2-barrel set-up, otherwise known as tbi.
My 350 tbi '93 came from the factory with 230hp! What a joke!
Even with all the mods I've done (and money I've spent), it's still probably not pushing more than 275-280hp, and that's at the flywheel.
Geez, they've got V6 minivans these days with more hp than that!!
When you try to do any mods to a tbi, there are so many airflow
probs, fuel flow probs, computer probs, and so much expense, that you might as well leave it stock in my opinion. I've learned this first hand by doing a lot of mods to my tbi '93.

Swapping on an $1200 vortec head kit on my '93 might give me another 20-30 hp, change the cam (more$$) and you might push that to 40hp, swap on a 454tbi/injectors(more$$), maybe up to a 50hp gain, and then you have all the chip burning/programming issues($$$$$$$$$$$$).
I'm tired of it. If I didn't have to worry about smog, I would have ripped that tbi off 2 years ago, sold it on ebay, put in a nice cam, and switched to a carburetor,;and saved about $1500 over the last 2 years.

That's why I'm going to put in an LS1. I can get a 2002 320hp LS1 complete with 4l60e and all wiring and ecm for $1200 (I know, that's cheap). Throw in an LS6 cam ($200), and you're talking 380hp. I can get the harness and ecm custom fit and reprogrammed for just $249! No fuel flow probs, no airflow probs, no more chip programming probs.
Give me an LS1. More horsepower out of the box. Shave a couple hundred pounds off the front end. Actually will be less expensive.
I'm sold.
Thanks for letting me vent a little about tbi's.
I know some guys have built them up to 350 - 380hp, but they spent a TON of money - thousands and thousands of $$$ - doing it, but, personally, I'm tired of pissing my money away on tbi mods.
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[Bruter]

Hey superchevy, I am just starting to think about upgrading my tired 92 305....then I came upon this post. I don't have to worry about smog checks in my area yet, so your comments on ripping off the tbi are worth considering. Then I could just get my 305 rebuilt with a nice carb, intake, cam, etc. Is it a correct assumption that in this case, the computer won't be used? Man...this is getting interesting!!

[superchevy]

Yes, you can do away with your tbi.
Do you have a manual or automatic?
If manual, no probs.
If auto, 700R4, the computer may be responsible for locking up the trans. You might need to get a lock-up kit from someone like Painless wiring.
If you're going to get a rebuilt motor, do yourself a favor and get a rebuilt 350 instead of going with that 305. You'll be glad you did.
If you use a rebuilt 350 with a pre-85 block that has a fuelpump location, you can use a mechanical fuelpump on the block and run a new line to the tank. If you use an 86-later block without a fuelpump location, you can use the stock fuel pump/tank and lines, but you'll have to use the Mallory 3-port fuel pressure regulator to adjust the 15psi tbi fuelpump pressure down to a carb-friendly 6-7psi, and use the other ports for the inlet fuel line and the return fuel line.
You'll need to get a trans TV cable bracket from bowtieoverdrives or another vendor to adapt the 700R4 to the carb intake.
There's probably a couple of other things I can't think of right now, but that's pretty much it.
It's pretty simple.
People will tell you that your mileage will suffer, but the gains in mpg over the years are mostly due to overdrive trannys - not, fuel injection.
If you want to learn more about swapping from tbi to carb, go over to the Camaro/Firebird board www.thirdgen.org and search or post on the TBI board. Those guys have been swapping their tbi's to carbs for a long time, and can fill you in on what it will take.
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[Chevyman69]

TBI cannot support a lot more than 300 hp naturally aspirated and its simple why. First even the 454 TB only flows a max of 500 cfm( Holleys rating is done at 3" of Mercury versus the way a 4 bbl is rated which is more real world at 1.5") and the fuel flow is restricted by injector size. Even at 90 pph with the ridiculously slow rate of speed the TBI computer( pump up the duty cycle sure, but then the engine speed is too fast for the computer to relay all the info and the curver goes all over) has its not really possible. Now no TBI 350 ever came rated higher than 210 hp, check out GM if you don't believe me. Now not slamming but 270-280 hp, umm no, you have a dyno sheet for that, you have less done to your trucks motor than I did to my 92's or maybe the same and it was no 270hp screamer. That number is tough to reach with cam, heads and the whole deal versus just bolt on stuff. TBI 350 193 heads are just garbage, they couldn't support that kind of power without a blower and the cam is pathetic. Off that will you notice a ton of difference with Vortecs versus L98's on a TBI truck, not really. The L98 is a good head and with TBI's restrictive system you aren't going to feel much of a difference. TBI is a very restrictive system, I know many people that try to make it run, one is a TBI 383, no matter what it runs not too bad until 4500 then it just dies, why, lack of fuel flow and air plus a computer that can't keep a constant timing and fuel curve much above 4500 rpm. You will be lucky to ever see 300 fwhp with a naturally aspitrated TBI 350, not something here people want to hear, but a sad reality.BTW my 92 had
65 pph 9C1 injectors, Edelbrock Performer TBI manifold, headers 2.25" duals, Accel coil, cap rotor, and rapidfire plugs, AFPR, Hypertech chip( piece of trash but whatever) and an open element Accel filter, maybe 230 or 240 hp, I could take 350 Vortecs but that was more I had better torque, not topend power. Anyone who disagrees with TBI's power chack around and see what real dyno numbers guys are pulling, they are not impressive, its a decent system for a torque engine, but nothing for topend. Look at www.thirdgen.org, lots of talk but no solid fast TBI 350 cars, and no impressive dyno sheets, why, TBI can't do it, guys keep beating their head but if its power you want the rochester 2 bbl TBI won't do it for you.

[Bruter]

Hey all!

Looks like I hijacked this thread as well...
... sorry canso.

I visited my local speed shop today...actually our only speed shop ... and he can build me a 350 with about 250 - 300 HP while keeping the stock computer. The only mod he would do to the TBI is to replace the stock injectors with higher flowing units. He also mentioned an Edelbrock exhaust system including shorty headers. Since my goal here is reliability with a bit more giddyup, any opinions on such a setup?

[Chevyman69]

250 ponies with 65 pph cop injectors and a cranked regulator with an all stock computer is a maybe. Its possible, but the fuel trim will be off for anything higher, not to mention the timing curve. The stock setup is set rich for compensation against lean conditions which would destroy the motor, not something GM wants( like the guy pulling the 30' RV when its 90 outside and the truck is all stock, if the rad can keep it cool it will be ok and it won't go lean). But that stock compensation factor won't support 300 hp, not at all. You need a burned chip to adjust duty cycle, fuel BLM's and timing and so on for the higher power. Now you should also get the 454's 2" base, the stock one can't flow enough air for any kind of real power. One other thing to consider is the camshaft. TBI is a very fussy MAP system, if it doesn't have enough vaccuum the computer assumes it always under load and it will never idle. Keep the duration under 225 degrees @.050" and run a 112 degree lobe sep or wider. The more vaccuum it makes the easier the motor is to tune. Check out what he wants to do cam wise and so forth, but either way a burned chip will make any modded truck run better.

[hills92]

hey superchevy were is the ex tube on your truck i have a 350vtec ZZ4 i am going to put in my 92 and keep the tbl i like the intake you have used i will go wiht that one were did you get it i think i messed it thanks