My 92 RS has a 383 basically stock 350 block and heads and a comp cam to fit the engine perfectly(so says the guy that built the engine) and basically everything else on the car is stock and also the 700r4. The car really hauls ***. I took a 91 5.0 mustang not problem off the line and he had very few mods. At about 110mph I was about 8-12 car lengths ahead and he had an auto also. So do you think the car should already, w/o the holley 502-6 should run in the 12 second range in the 1/4 mile? Thanks guys

 

Well, it's really hard to tell do to lack of information. It sounds like your car hauls pretty good. What suspension mods do you have? Do you still have the stock stall? Gears, posi? You said without the holley 670, so I assume your running a stock tbi or maybe a carb? If your running the stock tbi and injectors, I would be worried about running waaayyy lean, especially if it's with a stock 305 chip. It's really hard to guess times(this may be better in the theoretical drag bourd), but I would think the best way outside of the track would be G-tech, or to find somebody that knows what time they're running and compare to them.

 

I think my car has posi. Its 25th anniv. but I am not really sure. I am by no means a mechanic, as you can see, but I do know a little. I think both tires spin when it burns out. Anyways, i have the same exact setup right now my 92 RS came with except the engine. Everything is stock as far as I can tell with the exception of the new front end I put in. I mean everything is stock. The car runs good most of the time but I am fixing to get the 670cfm holley and then have a custom chip burned. The car most of the time runs real good except sometimes it bogs down but I think that is because it is running way to lean. Do you recommend i make some adjustments ont he stock suspension and what other mods would you make. I am definately going to get a better tranny for sure but what elso would you guys do? If you recommend mods for me let me know exactly what I need so I can plan to save and order those parts. Thanks again, Danny

 

As far as I know all of the RS automatics came with wimpy 2.73 gears and no posi. So that is one thing you should take car of. With that beasty of an engine 3.42 or 3.73 gear and add the posi for best results.

Sounds like your running stock 305 TBI with stock chip. Your not running lean, your running DANGEROUSLY lean. There is no way those 305 injectors are keeping up with a decent 383. Depending on the heads and cam used the very minimum would be 350 injectors with increased fuel pressure or the 454 injectors. You should also invest in WINALDL to look at the data from the computer to see what is going on in that engine.

The Holley 670 TBI might help some of your problems providing that you are using a good intake with it.

 

When you say dangerously lean will that hurt my engine until i get my new TBI and intake in a couple of months?

 

Yes

 

So what should i do? I have to drive it, it's my only car.

 

No full throttle action until you take some action.

As a cheap solution, you can put about 3 quarters $.75 in the fuel pressure regulator under the spring and increase the fuel pressure. This is not the best solution but it will move you from the dangerously lean to the lean condition on top end and may run a little rich on the bottom end but would be safer on the engine than the way your running it now.

I still recommend setting up the WINALDL scantool and looking at the data from the sensors on your car. That way you can tell just how lean its running and how much knock your engine has because of it. It's a $150 (laptop, AC/DC power inverter, software and cable) well spent on tuning a computer controlled fuel injected engine that has been modified to the extent that yours has.

 

I have the adjustable regulator on my stock TBI and I adjusted it to 16psi and that seems to be about the max and it did help quite abit. As far as the winaldl i have the software downloaded and the laptop but i still need the interface cable and do I need so scanning software to go along with the winaldl? I have no idea how my setup is supposed to be tuned where would I go to find out what a 383 with the holley 502-6 and other changes I made should be tuned to? Thanks alot for your help I do appreciate it. Danny

 

You may have to change the fuel pump to get more than 16 psi. That is close to stock pumps max and if your pulling more than 300hp out to that 383 which shouldn't be hard then that pump is going to supply enough fuel anyway.

On the WINALDL, concentrate on the BLM value during normal driving. 128 is perfect. Higher= lean and lower = rich.

Under wide open throttle conditions the computer locks the BLM value at 128 and you must monitor the O2 voltage to see how its running. You want the average voltage to be between .8 and .9 volts.

You also want to keep an eye on the knock counts. If you get more than a dozen counts on a 0-60 wide open throttle run that's bad. 3-6 would be normal.

 

Ok I will try that when I get the cables and software to do that. What about, for now, can I get bigger injectors for the stock TBI maybe from the 454 TBI or another 350 TBI and just throw them in there?

 

Its hard to say what size injectors are needed without knowing which 350 heads were used and what cam is in that engine. You could be making anywhere from 280-380hp from that engine based on those components. WINALDL will tell as to how lean that engine is running. Just go easy on it until you get that cable made and software setup.

 

OK, I am now talking to the guys on the PROM board for help. Thanks for your time. Danny