1991 RS 305

So last winter I did many mods on my 91 305 tbi. I still need to complete a few things such as tuning and what not. I want to clarify some myths I came across when doing my researching prior to my mods. First off here is what I did:

- Vortecs milled to 56cc w/ comp springs
- 1997 lt1 cam
- edelbrock performer RPM air gap
- Ultimate TBI mods including bumped fuel pressure
- .75" intake spacer
- injector pod spacer
- hooker 1 5/8 primary tube headers, no emissions
- hooker y-pipe
- converter delete
- timing at 12* adv., premium fuel
- open element air cleaner

- things I need to do-

-TUNE- I am running stock tuning
- cat back, crazy enough I have stock exhaust pipe from the y pipe back
- I need a bigger TB, 454 or holly
- fuel pump

-How she runs-

- Some posts said this combo would barly run on stock tune, It runs very strong to say the least. Pulls strong to 5800 rpm's which is about as far as I will take her.
- Only issues i have is when it's cold, first few minutes of run time can be boggy if the weather is cold, somewhat due to the intake and i'm sure tuning. overall once it's warm, it runs phenominal. I am sure i'm choking it with the TB and stock catback. Even with that it runs real nice.

- some posts made some concern as to weather or not the fuel pump could feed her, I am running the stock TB with ultimate TBI mods and bumped pressure, but I am having no fuel delivery issues at this time. When I switch to a bigger TB and finish the exhaust, i will swap out the pump as I will be pumping more air through her and don't want to risk anything.

- This winter I plan to get the rest complete, but for those of you working on a budget as I am, you can do a little at a time with very little driveability issues.

One thing to add, my car is a manual which helps the driveability a bit.

Good luck to any who undergo these what seem to be common mods around here. I drove my car all summer with these mods with no problem and just wanted to let people know how she runs if they were thinking of undergoing some of the mods but were afraid of driveability issues as I was. I know all of us can't afford to rock out all the mods at once, a little at a time seems to be working real well for me.

Good Luck, Matt

robertfrank

iTrader: (27)

I bet once you tune that thing it will run like a raped ape.if I were you I would go with an Xtremefi 46 mm tbi.People had been known to have issues with both the Holley and 454 unit's.

Fast355

iTrader: (2)

The only issues that I know of on the 454 unit is the fact that the manifold needs to be opened up to match, the minimum air rate screw needs to be reset, and a TV linkage needs to be setup if you have an automatic. After that the 454 throttle body works great when tuning, even on a HP 305.

Wait until you get into tuning and are able to bring out the combos potential.

DLV555

iTrader: (1)

That sounds awesome. Good luck with tuning. I'm sure most of us look forward to a dyno run or an ET. I had been contemplating an air-gap intake, I thought maybe the TBI wouldn't be happy with it. I'm interested to see your results!

1991 RS 305

thanks for the TBI tips. Appreciate it. I won't get any times this year any more, but in the spring. I hope to get the tuning, exhaust and TBI on there before spring.

90c350

Hey sounds like a great runner, I was just wondering if your 12* of timing is with the computer taking control or if the connector is dis-conected??? Im putting in my 350 soon and dont have my burning stuff yet either. Air-gap edlebrock rpm ,xe256h comp cam, shorty headers, holley adapter and ultimate tbi mods. 3" exhaust without cat etc. I would like to run about 10/12* initial advance but have been told that that would be to much without proper tuning!! Thanks for you thread it will help me be more confidant that this thing will run ok with the stock tune.

Fast355

iTrader: (2)

10-12* of Initial timing will give you 30-35* of timing at idle. WAY TOO MUCH. The reason he is able to get away with that much is because the MAP sensor is reading much higher than with the stock engine and puts the timing at a different spot in the MAP.

90c350

So if my cam changes the vacume reading at idle I should beable to bump the timing slightly to compensate until I get my prom burning eguipment??? With my current cam, My engine at idle I can get about 16hg of vacume at 700rpm with a carb. How will this affect the map?? Thanks for the help Fast355!!!