Hey guys,

I've just recently purchased a L98 Long block for $175.00 (90k Miles). I was going to repin my TBI harness and pick up a Stealthram and go multiport, but my funds just went south... BLAH

Anyhow, I am going to have to work with my TBI until that picks back up. I'd throw a carb on, buy my plan is to stay Fuel injected and I hate ot remove it just to put it back on in the next year. SOOOOOO

I plan on getting an AUTOPROM and I believe I can tune with that (You can with 730 I'm not sure about the 746' but I think it can. But I still want to try to save some money right now and even wait on that.

So, I am going to drop in the Stock L98 Longblock in and add a HOOKER 2055's/Y and 3" FLowmaster Exhaust kit.

Now to my questions:

1) Will the L03 Intake manifold work with the L98 heads (I know it will bolt up, but question is more along the lines will this supply enough air for the stock L98). I know this is not going to be a horsepower king, eventually yes - I'm hoping for around 220-240hp.

2) Is the 305 TBI the same as the 350 TBI??? And if so, what size injectors do I need to get??? (Or from what vehicle ie: cop car).

3) Will say a L05 Cop Car chip suffice this engine for now??? (I'm going to get into Chip tuning but i'm trying to do this as cheap as possible at least for the next couple of months). Or will that Chip not work at all on the Stock L98 w/ Headers. I honestly have no clue. Thanks all for the help.

 

The cop car chip will allow the car to run but don't expect it so be sufficient. I am glad you are going to do the chip work because it is crutial to any TBI system. The LO3 intake will bolt right up. It is garbage as far as performance is concered but it will work for the time being. If you had a carb intake laying around you could use that with an adapter plate. The 305 and 350 TBI units were the same with larger injectors being equitp on the latter. See if you can scrum up some 350 TBI injectors from a junk yard. You may want to replace the fuel pump while you have your tools dirty. The stocker is ultra weak and will not provide the fuel you need. Don't forget a 350 knock sensor. You may want to get a 350 ESC module as well although I have been told the 305 will suffice.

 

you dont think his stock fuel pump will support basically a LO5 with L98 heads? or does he have the L98 cam as well? I guess that would put him border line.

the injectors are orange/black and rated at 55# i believe for a 350. cop ones are 65# but 55# will still work if you crank em up a little bit. I swapped mine last night (stock 305 to 350), as well as my ESC/knock and my 350 finally runs like it should. I have a pair of injectors if your still looking for some. They need to be flow matched though. I would keep all of these parts as junkyard pieces, because youll be swapping them out again once you go to speed density anyways, (youll need new knock sensor again and ESC isnt used by speed density). Sent me PM if you need help looking for parts.

 

I have a friend who should have these cop car injectors, but thanks anyway. :yourock:

I think I am going to do the Cop Car injectors and then the Cop Car chip with this Stock L98 - L03 Manifold - and Headers/Exhaust and then I'll post my results. Especially since there doesn't seem to be much info on this board in regards to a L98. Several L05's, but not L98's.

Anyhow, I'd even like to dyno after these mods, just not sure where a dyno is in the greater Indianapolis Area. (I live in Shelbyville, IN). That way it would give people some realistic numbers. I think I'll be happy since minus headers/exhaust I'll only have a hair over $200+ dollars in this entire swap.

I see that Tunercat supports the 746, does anybody know if TunerPRO supports it? Reason being Tunerpro is where I plan on going with my Speed Density setup and would rather avoid paying the 100 for Tunercat if I can. If not, what is a popularly used program that TBI people use?

I'm hoping I can get the topside of 240 (So I can run with the L98 guys). But I'm afraid I'm gonna be short with the Stock L03 manifold. But ya never know. We'll just have to find out!.

 

To let you guys know how cheap I am going now, I just turned down a 2800 Vigilante TC w/ Lockup for $400.00 in favor of a $25.00 used S10 converter (93+ 4.3L) = 2200 Stall, hehe. :shrug:

 

It would be very close. I doubt it would feed what he needs at WOT. Especially with the larger injectors.

 

Hey guys, I have done some more research and I'm going to pick up a Performer RPM and run that in place of the STOCK L03 manifold (those are not that much money).

What do I need to get into the chip burning. I have Tunerpro RT "unregistered" for now on my computer. Once I get going I'll send Mark $30 just to show I appreciate his time and effort.

I want to purchase the AUTOPROM. My only fear is that the AUTOPROM does not burn the chips on our 746 computers. So Is the G2 adapter all I need to install to take care of this problem?

Also, what is a realistic power level achievable with TBI so I know when I need to start thinking about MPFI?

Thanks!

 

Check out the stickies above to find links on chip tuning. I would look into the Prominator since you can make changes on the fly.

 

I thought the AUTOPROM could do this as well, maybe not.

I'll have to do some research and see if the PROMINATOR is compatible with 746 and 730 ecm's.

 

I have the Prominator, and I think the Autoprom does tuning on the fly too. I think Autoprom is the better choice for you since you're moving to a 7730 later on (Prominator solders on your ECM, Autoprom does not). All you need is the G2 adapter soldered on your 8746 and then use either flash chips or EEproms and the Autoprom to burn them. Look at Moates.net or even email him and ask him any questions. I've emailed him and had him respond in under 5 minutes.

I think, so far in the TBI community 400hp is considered the reachable limit for 2bbl, but not many have pushed the envelope or tested beyond that. the 454ss guys might be the highest 2bbl power levels.

 

It looks to me the injector sizing tends to be the limiting factor not airflow.

I wonder what the solution is. Most likely for me it is going to be MPFI.

I have thought that the Dual TBI idea is a cool way to go. The only thing is the fact the 746 only has enough drivers to run 2 injectors. I know you need 2 more injector drivers. I am not skilled enough electrically to figure this out, but I know you could potentially use the drivers off of another 746 no? So somehow we have piggybacked one ecm with another ecms injector drivers. I'm sure this can be done. The tricky part would be I would imagine the idle circuit and what to do with the IACs. I'm suprised noone here has tried this or at least if they have I can't seem to find any posts of anyone who has done this successfully.

I wonder If you could use nitrous injectors and progressively inject fuel into the engine when you start getting up to the injectors going static?! Like about 4000rpm and it starts to go lean have the secondary injectors inject fuel to get you back to 13/1 or wherever you want to be...

I dunno just thinking out loud. It all sounds cool but I'm sure the time/money spent will have diminishing returns when you have MPFI (7730) readliy available and prices for items (HSR for instance) dropping prices across the board...

 

I'm planning on getting for my 8746. Bill at Speedtronics confirmed it works with the 8746 and 7730. They recently announced a new product they're working on called SpeedReader, which will make C3's (like the 8746) as good as a P4. Not sure how long till they're ready to launch it.