90Formula305

After reading all the stickies about how to get our TBI's to perform it was kind of an inspiration to make me keep mine, i still want a bigger motor. Which i have sitting in the garage ready to be machined....BUT i DESPERATELY want to get rid of the slushbox, i hate it. So i am looking at getting a wc-t5 from jegs or summit, my question is besides getting the prom retuned for the bigger motor will i need anything changed because of the transmission swap or is the tbi computer not as complicated as say swapping a t56 into an a-4 4th gen? Also im sure it could be done but just for clarity, would it be possible to have at least up to 450 horse with a tbi setup because i really want to get the 350 i have done into a 383?

90Formula305

Anybody, an answer to at least one of these will help.

dimented24x7

iTrader: (2)

T-5s are no longer available for our cars and theres a good reason for it. Those ones in the cataloges are for mustangs.

A T-5 wont stand up to a decent engine. The case and internals arnt strong enough. Other options are the TKO/T-56/Richmond 6-speed. I ordered a tko myself but I dont have any useful info on how its working out yet. Havnt even recieved the trans (must be shipping it by mule or something).

As far as tuning, theres not much to be changed with these computers. Mainly the idle and the TCC. Also some changes to how the throttle follower is handled will also help. Thatll keep the engine from immediatly dropping to idle when you shift gears. With the auto cals itll already have more then you need, anyhow.

dimented24x7

iTrader: (2)

With the later computers, theres alot more stuff there for use with a manual, like proportional control routines and such to make the engine operate more smoothly with a manual. You probably could get away with just using the auto chip.

90Formula305

They dont supply them to the wholesalers, or they just dont make them anymore at all? Hell i like the idea of a 6 speed better anyways, so you think i should be fine with my chip right now though?

kyles88bird

u should be, might get a SES light from it not gettin a sig from the toruq convert. but ill talk to my buddy who just did the swap on his 91 rs maro. if u do swap tho, go the 6spd route and then throw some 3.73 or 4.10s out back, better perfomance and if not better gas milage as u'll have two extra gears. i threw the 3.42s in my car and it gets alot better gasmilage then the 3.08s did

dimented24x7

iTrader: (2)

No codes w/o the TCC. The ecm will blindy activate it regardless of whether the TCC solenoid is there or not.

dimented24x7

iTrader: (2)

They make the HD replacements, but not for the f-body platform. Thats what the f-body TKO was intended for.

90Formula305

Ok now to my next question, would it be possible to actually build a street rod out of a tbi setup? cause i seriously want a 383, will i be able to do this, im hoping for 400-450 horse, possible?

BMmonteSS

Only if you and your ECM become good friends. Gotta look into tuning. Check out Ben73 he's the fastest that I know of right now.

dimented24x7

iTrader: (2)

The only special consideration is that youd want to make sure that you dont have an engine that needs tons of fuel at WOT but needs very little at idle. With only two injectors youll have trouble balancing the fueling demands. A 383 with good heads (AFRs, moded vortecs, etc.) and a mild cam like the zz4, mild comp. cams roller, or something similar would be a good bet. Good heads are definatly key. You want good port flow so there isnt a need for an aggressive cam to make power. It wont be a bear to tune and itll make good streetable power. Id say around 1 HP/CU would be obtainable.

90Formula305

there is a 4 barrel tbi unit from holley isnt there, would this work correctly? I was thinking of .500 lift with 112 lsa, yes or no? also i have a 4 bolt 350 in my garage. Now im thinking since maybe its a 4 bolt it had to have come out of something pre 75 also the heads are pretty decent size valves, 1.94's if somebody could give me a link to a site where i can put casting numbers in from the block and heads to see what they came from and will the 6 speed bolt up to this and can someone give me the part number or a link to a site that sells it, thanks.

dimented24x7

iTrader: (2)

Yes, there is a 4 barrel unit available if you look around. Youd have to make an injector driver to drive the second two injectors. For that matter, youd also want to be able to control the second set of injectors so theyd only come on past a certain throttle opening. This would allow you to idle on only two of the injectors. The tbi is rather pricey and theres some work involved on the control side with the extra injectors. A standard 2" tbi with two injectors can feed a decent ammount of power but idling will be a problem, which is why youd want to use a mild cam.

90Formula305

Is there anybody on here who has used that tbi unit before, or is there a tech forum or a link on how to make the driver? Earlier i remembered that i have a edelbrock torker intake that my dad had used on his .30 over 327 '55 chevy a long time ago and i remembered reading that you can use carb intakes on tbi so i dug the intake out (its a semi high rise, mid-range power?) It matches to the heads, while i was seeing if it would fit i noticed that the heads were center bolts. Irrc ALL vortecs were center bolts? So if these are vortec heads i can have them ported and polished and possibly ground to fit larger valves, after that i'd have a pretty sick set of heads on my hands, with new valves, springs and rocker arms (aftermarket of course ) these should flow some pretty high numbers, correct?

BMmonteSS

no not all center bolt heads were vortecs, vortecs have 8 intake bolts vs. 12 for the old syle. They are probably swirl ports.....not what you want on a 400 hp 383. You HAVE to get a set of good heads to break 400 hp with a mild cam. Just to let you know I know of only one person ever to run a 4 barrel TBI off of a GM ecm and he ditched it later on if I remember correctly. Making over 400 hp with TBI is very doable, but you have to really understand the system and feel comfortable with it. The guys helping you out right now, including me, don't make 400 hp. It's one of those area's that few people trek to, so keep that in mind. This won't be a bolt on and go situation.

dimented24x7

iTrader: (2)

There used to be someone who carried the boards, but theyre no longer available. IIRC, there are still schematics around for it.

The real issue isnt as much airflow as its getting good dynamic fueling range. You could use a vacAFPR, which would be the saner option, but no one really makes vacAFPRs with more then a 1:1 manifold to fuel pressure ratio. That and youd have to coordinate the ecm as well so it will see that theres a change in fuel pressure.

Basically what it comes down to is that the system can handle quite a bit of power, but no companies make the necessary components to do it with, say, a 327 or a 350. Best bet at this time is to run with a 383 or a 400 with a mild cam, good heads, and prom burning equipment. There are some other benifits as well, like you wont have to pay top $$$ for a rotating assembly so you can rev that 383 to 6500+ rpm to make peak power.

90Formula305

so all i need to do is count the intake bolts to see if there vortecs? Could you guys give me some cam suggestiions then, id like it have a noticable idle and scream under wot and should i even ask about forced induction?Would this be even worth trying with the tbi or should i just say **** it and go carb? Would the 6 speed work with a carb'd motor?

dimented24x7

iTrader: (2)

I think you can get the power you want with TBI, its jsut a matter of how the motor is set up. The other option is to go with MPFI. If your subject to emmissions testing, then carb would definatly be out of the equation. To add to that, if you have emmissions, then the larger stroke engine with the milder cam will pass much more easily then a cammed engine of smaller bore/stroke.

90Formula305

alright guys i was digging around the basement last night and i found two hydraulic cams, ones a .480 and the other is a .521, which one should i use? hmmm hmmmm hmmmm.....

dimented24x7

iTrader: (2)

The lift is more head dependant. Ideally you want the most lift/aggressive lobe profile for a given duration that the heads can handle. Assuming the runners can keep up, the more lift you have under the 'curve', the more youll get out of the heads.

90Formula305

When did swirlports come out exactly, arent the valves too big for it to be crappy heads like swirlports?

dimented24x7

iTrader: (2)

I think 87 was when the first started appearing. On the small block, there where 305 and 350 versions made. You can tell by looking for the ramps in the intake ports. They visually obstruct half the intake valve when you look down the runner.

90Formula305

so now i kind of doubt that the heads i have are swirlports, cause nothing in the 80's was made with a 4 bolt except the vette right, and the valves are pretty big to be swirlports, i would hope so anyways. Any ideas?

dimented24x7

iTrader: (2)

Get the casting numbers off the heads. Thatll tell you for sure.

90Formula305

where can i look the numbers up to find out the specs on them?

90Formula305

also if i was to switch to a tpi (or any multiport setup) with mass airflow how often would i need to get the computer retuned with internal such as cam, heads, intake manifold or upper intake plenum? Or will it sense the change and compensate for it?

90Formula305

ok, i was bored so i pulled the valves off the heads a couple minutes ago..............swirlports. Excuse me while i go throw up all over the garage......................ok im back i guess now all i can do is order a set of bare castings out of jegs and build a set myself. I must admit that was a thoroughly depressing discovery, anybody want to buy a set of heads? Now im pissed off. Oh and by the way the number on the side of the block reads "638", any ideas?

dimented24x7

iTrader: (2)

Youd have to get the complete casting number off the rear of the block if you want to learn anything. www.mortec.com will have loads of casting numbers as well as all the common locations.

dimented24x7

iTrader: (2)

The stock TPI really wont handle a large displacement engine. The stock MAF is an 8 bit system that only reads up to 255 g/s of airflow. Youd have to basically fudge it to get the right ammount of fuel at WOT. The later SD tpi systems would work, and is what Id recommend if you where to use OEM hardware. Id also use a good aftermarket mpfi intake of some type to complete the system. The SD computer, and any respectable aftermarket SD system, will need a fair ammount of tuning to get them working properly. Once tuned, though, they never need retuning if the engine setup remains the same.

90Formula305

Would i be able to just hook up a multiport setup and use the computer that is currently in my car?

90Formula305

Also Could any of you guys tell me how far into mods i can get with my stock tbi right now? I was thinking headers, new intake manifold, msd distributor, msd blaster coil, msd wires, new plugs of course, i already have a flowmaster cat back, i was thinking of either a 3.73 gear swap or 4.10's after i get the 6 speed. So would any of that make it run to lean? If so could somebody give me a list of parts i can safely use before it gets dangerously lean? Thanks.