weberusn

Is anybody making a good hp and torque with a 383 or 350 and tbi setup? Just wondering. I am builing a 383 currently and am trying to decide on whether or not to use the 670 holley tbi or a carb. I have both just looking for suggestions.

Thanks

Token

The upper limits of the 670cfm Holley is ~360 horsepower. If your 383 is gonna make more than 350 horsepower I'd suggest going to carb. You could always use the Holley Commander 4bbl TBI but thats way expensive.

weberusn

Thanks for the reply that tallies two up for carb so far. How did you find out the upper limits of the 670tbi?

Token

The largest injectors made for the 670 are only 85pph, and that's not enough to feed much over that mark. Someone had a mathematical equation and I've yet to see it disproved, therefore I'd say that's the "limit" without doing something else... Twin TBI anyone?

r90camarors

From personal experiance.......

The Delphi injectors are underated, AND the formula is not as accurate as people would like to believe. I have plenty of fuel, it's air flow that you need to be conserned with. And if you are really worried about fuel, you can always bump the pressure up.

Though I never had dyno numbers with my combo, or track times after the changes, I can tell you it was well over 360hp. First it shattered my clutch at the track, then after a spec stage 3 clutch, my t-56 (rated at 450lbs/tq) started feeling the effects, I lost 5th all together. Unfortuantly, she spun a bearing, but this time around I may beef up the bottom end a bit more to possibly handle a nice shot of No2.

I did put a 12.5 sec LT1 formula to shame, as well as my buddy's 12.7 sec mustang several times. Had I actually ever got traction, I am sure I would have been in the 11s.

ShiftyCapone

iTrader: (7)

You give TBI a good rap. This is what can be done with the right selection of parts and tuning. Lots of people do it wrong and get disscouraged. You are proof that TBI can be a performer. See TBI isn't so bad now is it?

weberusn

RScamaro, did you burn your own custom chip or did you outsource? Just curious. Oh yeah where did you get your fuel pump and afpr from?

Thanks

ShiftyCapone

iTrader: (7)

It says in his sig that he got his chip from tbichips.com so my geuss is that he data logged a whole bunch and was in contact with those guys. I am pretty sure he is running the regulator that came with the 670 unit. He will chime in I am sure. The walbro pump can be purchased from a whole slew of places.

Token

:hail: :hail: :hail:

weberusn

r90camaro, what do you you think would be a good set of heads and manifold to use with this camshaft:

Comp cams 12-404-4

It is a non roller cam. I have a older style 350 with a fourbolt main.

Thanks for you guys advice.

r90camarors

Unfortuantly, I haven't gotten into burning my own chips. Brian at tbichips.com did my tuning. Unfortuantly, I only went thru 3 chips with my 383, and still needed much done to the chip, and know there was much to be gained, but I could never get around a false knock count I had, and thus never got the timing table dialed in. I definetely recommend tbichips.com if you do not burn your own chips. He did a great job with my 305. With the stock intake and never lifting a valve cover, I trapped in at over 91mph. Of course that was with a slew of other mods like gears, headers back , and the t-56, but very respectable given the LO3 thanks to brian's tuning. Brian is friendly and very communative, and willing to help. And the only reason my 383 chip was off was because I was always doing drastic changes between burns, and of course, the false knock. I did switch esc and knock sensors, I think maybe my exhaust was just too loud and rattled too much.

I am running the regulator that came with the holley 670. I swapped in a slightly stronger spring that adjusts up to 25 psi. The stock holley spring yielded 22.5 psi.

weberusn

r90camaro, thanks for the insight. I am going to contact Brian about getting a custom chip burned. When you say the regulator that came with the holley 670 are you refering to an internal regulator? I have one of the older 670's from what I am told so I was just wondering. Did you replace your fuel lines to run 25 psi or are they enough to handle the pressure? Thanks for your responses they are very helpful to me.

Bill

r90camarors

weberusn,

what are the specs on that cam?

I am really satisfied with my pro topline vortecs and rpm air gap combo. I have heard numerous times that the rpm air gap is the way to go if using vortec heads. I like the pro toplines because they produce better numbers than gm's and can handle a .550" lift stock. I have mild bowl work done on mine, but if I can afford it on the rebuild, I'm going to go a little better.

Single planes are also worth looking into depending on the size of the cam. I am a firm believer that single planes do wonders for the 2bbl tbi based on both theory and personal experiance. Simply opening up my adapter plate made for a sotp difference, and doing so creates a mild single plane effect due to the open plenum space. The only reason I have not put a single plane on the to do list is because I do plan on swapping to the 900cfm commander 950 system down the road so a supercharger is a little more feasable and tunable.

weberusn

Here are the specs on that cam:

Rpm Range: 1800 - 5800
Cam Grind #: 268AH-14
Duration @ .050" : 222/226
Lift w/1.5 : .464/.464
LSA : 114 degrees

It is the biggest cam that I could find with a 114 that was a non roller since my block is a 79.

I am planning to use 1.6 rocker arms to get the lift to almost .500. That I will think will be good for this engine. So you like the protopline heads? How much are they for a pair? Is there a good place to buy them?

Thanks again for you help man.

r90camarors

Bill,

The regulator is on the holley itself. If yours is untouched, then there is a brass cap you need to remove. It is easy, and a 4mm allen stock (I think) is all you need to adjust it.

The stock fuel lines worked for me. However, I did install braided fuel line from the rubber lines in the engine compartment going to the tbi, for both the feed and return line. I did this because the tbi is moved after intake swaps, and the stock lines only bend so far. the braided lines made life much easier

weberusn

That is cool. I was planning on using the differrent lines like you did in the engine compartment. I saw that on this guys website from this message board and ordered the stuff.

Do I get the new spring from Holley?

r90camarors

Bill,

Do a search on the pro topline and you'll find what you're looking for. I had my engine built up at a performance shop, and went on an overall budget, and not quite sure where they got the heads or how much they were. I know they were bare, but I think all the topline heads are. I really wish I was confident enough to build my own engine, but unfortuanly I limited to simply swapping engines and working on the upper half.

I actually got the spring from another member on this board. It was from a 454 ss truck. I saw a FI regulator in a magazine somewhere that had a nice range on it as well. something like 25-70 psi.

weberusn

Thanks for the insight on the proline heads. I will do a search for them and check them out. If you have any tips on where I can get a t-56 and rear end please send them. I know the stock stuff is not going to hold up very long.

Thanks

r90camarors

As far as the t-56 goes, it looks as though http://www.ddperformance.com has some of the best deals. I will probably end up using their rebuilt t-56. It's rated at 500 lbs/tq, and the price after core charge is pretty close to what a partial rebuild on mine would run. I'm going to check up on shipping charges though, and make sure it is worth it. Their aluminum flywheel looks to be pretty nice as well.

As far as rear ends go, I am going with a moser 12 bolt with a 3.42 gear set. I would recommend going this route. I like the 12 bolts over the 9" because they are lighter, more efficient, a little more $$ friendly, and I avoid using something with the F name on it.

The only time I ever had any kind of traction was at the track.....if you want to call 2.0xx 60' traction needless to say, my rear end started whining pretty bad after those runs! I'm sure a set of slicks would have ate the ring and pinion alive. Though I'll tell ya what, the z-28 slip off posi has held up really well. There is a tech article on this sight on how to beef up the 10 bolt, and may be a route you're interested, but a 12 bolt or 9" is a sure bet

weberusn

R90camaro,

Hey what's up man? Thanks for all your help. Even with all your help I still have some questions. Well just to get you up to date...I ended up purchasing some vortec heads brand new from a friend for 300 bucks with the stamped rocker arms and nuts. So that will have to work for now. Since my budget doesn't want me to spend any more than a certain amount. Also, I purchased the air gap intake it looks kick ***. Well here is my problem. I have an older style holley 670 that I bought about 2 years ago with intentions of using for this build up. Bought it on ebay. It has to be really old. I has no place to screw in the Idle air controller motor and has an electric choke. Is there any way of modifying this work? If not what is the largest injectors that I can use on the 305 tbi? All I have left to purchase is a fuel pump. I am done building the shortblock and am waiting for the heads and intake so I can button them up. I am stoked. Any help would be great thanks man.

Bill

r90camarors

Honestly, I am not too sure how or if you can make your holley 670 work. But you still have a few options:

1) Try to find a newer holley base on ebay and go from there
2) Go with a new holley 670. I bought mine through auto zone for $300 new. The most common is the 502-6 (comes with 65pph injectors). I origionally went with the 502-5 w/ 57pph injectors for my 305 because my stock injectors took a dump and I figured why not go with the larger unit. I bought the 85pph injectors when I swapped engines, but you may want to give holley a call and see if they sell the 670 with the 85pphs already in it.
3) Do some research on using a 454 tbi. I have heard some negative things about it, but it is still worth looking into. I believe there are 80pph and 90pph injectors (not quite sure) available for the unit. Technically, you could use them in the 305 tbi, though it would never flow enough air to need such fuel. It seems the largest injectors people run on the 1 11/16" tbi are the 65pphs.
4) You may want to look into the commander 950 system. Its $1,400, but comes with pretty much everything you need minus laptop. I know it is exspensive, but the price is extremely reasonable when taken into consideration. And from experiance, you will make more power with it. My engine, as strong as it is/was, was always starving for air up high with the 2bbl. Every mod I did to yeild greater air flow made for a sotp difference.

Also, I don't know what adapter plate you plan on using. I used holleys, but I am not satisfied with it. I think the tbi is too far foward and the design actually restricts airflow. I opend it up, and angled the bottom of what was left, then polished it. It helped a ton, but I think it was still limiting do to the overall design. So the other option is to have a machine shop make you one. Check out z28boy's page before you install the intake. He has some very good info and pics. Basically, he had the intake bored to match his adapter plate, because the 2" tbi is actually a little wider than the square bore intake.

Hope this helps, and feel free to ask anymore questions,



Roy

weberusn

Roy,

Do you think that I am going to need a new hood with the airgap intake? What hood are you running? I am going to look online at ebay and the sales board here for a new base or maybe assembly depending on price.

Thanks man,

Bill

Low C1500

Tbi can make lots of power, I do think that it chokes my motor off a litttle at 5500rpm+. So its difficult to make lots of peak hp. But tbi has no problem making lots of tourque. This winter I ported alot more on my thottle body, and intake/heads. As soon as the snow melts I'll see how it goes in my truck.

If your willing to put the time and effort into getting a good custom tune, then tbi will give you a nice street machine.

weberusn

Low c1500,

Thanks for the insight man. You set up sounds sweet. I think that you and I are running the same cam. How do you like it? Hey how hard was it to run the 454tbi vs. the holley 670?

Thanks man. Oh yeah I saw you truck on your site looks sweet man.

Bill

Low C1500

I love this cam (I think its the same one as you), I have better bottom end power than I ever did, as a stock 350. I like the 454 tbi, as its been real easy to find injectors. I cooked my first 90lber's then I ran 55lber's all last year at high pressure, now I;m back to 90lber's.

TBI has a bad rap, I think only cause very few people have "built" motors using tbi.

r90camarors

Very, Very true

You may be able to get by with a stock hood if you cut out the places for the blisters under the hood, use a 1/2" adapter plate, and a very short open element. But I would not risk it, it would be very very close, plus I really doubt you want to use an 1" tall air cleaner.

I am using the Cervini 3" cowl, and love it. It fit perfect, looks awesome, and is very well constucted. I posted pics a while back, do a search and you will find them, or else I can post the link. It was $400 plus shipping. My shipping was a little over $100. It comes gel coated white, and had a paintable underhood.

weberusn

Hey do you all know if one of those big block hoods will give me enough clearance? They sell them at thirdgenresource. I think they look pretty sweet.

Thanks Bill

r90camarors

I'm not quite sure if the big block hood will work or not. You could probably post the question on the body and interior board though.

swerve-driver

Very true. I did a vortec 350 with a stock tbi and 65# injectors that is working well int erms of performance, fuel economy and emissions compliance.

There is a ton of insight on this particular post. The guys that have posted so far (not specifically including myself) have been around the block, to say the least.
Whatever other questions come up can almost certainly be answered on these boards.

I can give you additional info on 383 performance later this year- I recently bought a brand new Jim Pace 350 10243880 block ($200-sweet) and am awaiting a balanced 383 rotating assembly from Competition Products. That will be fun.

I guess the answer to your original question (carb v. tbi) should mostly be based on your intended usage- desired fuel economy, performance, emissions compliace, etc....
From my point of view, it can't get any easier to tune a car than sitting in front of a computer, telling the car what needs to be done at a specific RPM-MAP condition. Of course, I did an awful lot of reading and learning to reach that point.

Whatever your choice, best of luck-
S-D

weberusn

R90,

What's up dude? hey what do you think about running stock tbi with all mods and 65# injectors until i can afford a new holley setup?

Bill

Swerve,

What kind of power were you putting out with your combo? Wht kind of times were you posting?

Bill

swerve-driver

I have not measured HP of the car. I can tell you that it has done 13.8 @100mph. That was on my 2nd pass at a dragstrip, ever. I'm no pro driver. Car is not stripped down or anything- it still has ac.
S-D

weberusn

Swerve,

Are you still running the stock t5 and stock gears? That seems like a pretty good time for you second time in stock trim.

Bill

swerve-driver

Yes.

weberusn

Good stuff man. I was hoping to run 12's with my new motor a t56 and some 4.10's. Maybe even getting close to 11's with good traction. You guys all make me think it is possible.

Bill

swerve-driver

Its all about torque, tuning and traction. And you can find the answers right on these boards. I can't say enough about this site and the people that make it great.
The UPS man just droppped off my 383 balanced rotating assembly, so I'm gonna go check it out-

Good luck on your build and please post your progress..


S-D

r90camarors

weberusn,

In regards to running the stock tbi- it really depends on how fast you need the project up and running. The stock tbi will still make for great drivability and throttle response once you have the chip tuned in, but your powerband is going to be very limited, I would have to imagine it would die off around 4-4.5k rpm. The 65pph injectors should work well with it as well, as I think that would make for well enough fuel for the limited air flow.

Also, take much into consideration in your rear end gearing. 4.10s and the .5 overdrive on the t-56 still make for very nice highway driving, but keep in mind your 4th gear (what you want to cross the quarter in) is still a 1:1 ratio.

I think 4.10s would be way too steep for your goals. My combo is something like 118mph at 5,500rpm in fourth with 3.73s, and that is running large tires in the rear. The 2bbl tbi is not going to be able to make too much more power past that in 4th gear.

I am going with a moser 12 bolt and 3.42s this time around, as I hope to be trapping in at 120mph, but with slightly smaller diameter tires than before.

Also something to keep in mind-the 10 bolt will not hold if you plan on making killer 60' times.

By the way your goals are very possible, just use everything as a resource and gather as much info as you can, and never be afraid to ask something. Best of luck

r90camarors

Swerve,

Just outta curiousity, any ideas on the knock sensor issue? I really think the 350 esc/knock sensor did not work well because of the stroke difference of the 383 like you mentioned before, but I have yet to come up with any ideas other than the dummy sensor, which really isn't a safe route.
As a matter of fact, Brian at tbichips told me that the timing in my chip wasn't even as aggresive as the tpi vettes had, yet I still always got the counts. Who knows. Any body know if the commander 950 system uses a knock sensor?

swerve-driver

Everything I read keeps saying that knock sensor must match the bore size, not the stroke. For some reason, I imagined stroke having more impact, but evidently, I'm wrong (https://www.thirdgen.org/techbb2/sho...ensor+AND+part)
Grump mentioned maybe using a new sensor and trying different esc modules.

Could this have anything to do with the trouble? https://www.thirdgen.org/techbb2/sho...ensor+AND+part

May also consider base timing and compression ratio?
S-D