Hello,
So I was hoping someone could shed some light on my swap? I just completed this last week and have swapped out my stock 305 TBI 91 RS camaro with a fresh rebuilt 96 350 with vortec heads, 30 over with rv cam. I then attached everything off the 305 to the new engine except the intake obviously and used an edelbrock rpm.. I ordered a conversion plate from ebay that will allow me to use my edelbrock manifold with my original TBI... So my question is... since I am still waiting for the part to arrive from Ebay before I can start the car... what problems will I run into? I used all the original hardware.. I deleted the smog crap and bolted the original exshaust manifolds leaving the one bolt out due to no where to place one on one side (will work I think)... any info you could provide would be great, IE: will I need injectors swapped? knock sensors swapped? ecu? ect ect...... Chip? Anyone done this?

 

I hope this doesn't read wrong, but I don't understand all the improvements to getting the air in, but none for getting it back out. Those stock exhaust manifolds are restrictive even on the stock 305s.
Are you using the 305 TB, with the 305 injectors? For what you're doing, you need a 454 TB and injectors, or Holley offers the same thing, only new, at 570 cfm.
The '91-'93 454SS pickup was making 255 HP, and if you get rid of those exhaust manifolds, you should be making more than that.
Your "RV" cam is really vague, and tuning could be extra difficult without exact specs.
Will all of this run on a 305 chip? I seriously doubt it. I'm not even convinced that an LO5 chip would work.

 

https://www.thirdgen.org/forums/tbi/...i-buildup.html

 

Well this all started with a stock 305 with bad valve seals... I found a built 350 vortec and bought it, was told by the builder to run a 600 cfm edelbrock (1406) and an HEI distrib and I would have 300HP.. anyway long story short.. I was buying all this to do the swap and found out I had to change allot of things on my 91 to make this happen...fuel pump, wiring, ect ect.. so I read on another post using my existing TBI setup will work and I can still achieve performance while maintaining all original equip.. Anyway to answer your question YES I have bolted everything from the 305 block to the new built 350 Vortec... so I guess im in bad shape.. it looks good and stock tho (lol) Where do I go from here? I am honestly waiting on an adapter plate from ebay to use my new edelbrock rpm manifold with my existing tbi... and was planning on firing it off..

 

If the 350 vortec has the stock cam (it produces around 255fwhp), the stock 305/350 TBI TB will work fine. No restriction up to around 280fwhp

To fuel a 260hp engine with TBI, you need either 75#/hr injectors @11.5psi with stock tbi fuelpump, or your 55#/hr 305 TBI injectors @ 20psi fuel pressure with a TPI fuel pump or similar.

(Other flow rate injectors are available too, will require different fuel pressures to support around 260fwhp)

Coustom tune is required, fueling settings in the calibration will be different for each configuration.

20psi with the 55 #/hr injectors will run rich @ idle and low load, this can be fixed using a VRFPR.
To set up the TBI ECM to use a VRFPR you will need EBL flash http://dynamicefi.com/ this will be really simple to tune with, it also has a calibration for L31 engine specs that you can use.

 

I can understand not having the funds to do headers right away. But until you get them, power will drop off very dramatically as the revs build. And once you do fix the exhaust flow, you'll need a dramatically different tune.
Thomas has posted some excellent help for you, but I've seen, in person, even a pure stock, dyno-tuned L05 with headers gain power with the larger TB, so do plan to do that upgrade when you can.

 

Thanks will get headers for sure... do you know if the Hooker headers #2460 will bolt to my vortec heads? And whats the best way around this ecu? not trying to spend thousands! I am already in this more than I wanted.. Anyone want to finish this... lol May just sell... also does anyone know what psi my stock 91 camaro rs 5.0 produces?

 

Will the ecm work? here is a copy of the listing..........

I have here up for auction a used CHEVROLET ECM computer that was taken out just reciently from a 1995 chevrolet truck.This ECM has the JEGS pro comp chip in it.It works perfectly.I did drive this truck before taking this out and really had the pick up and go.This is the part number 95ck 15/25 350eod s2.This is a plug up and go computer.As you can see in the pictures I will be sending the delievery reciept with it and origionally cost from JEGS for 159.99 plus handling 18.98.This would be a great addition to any truck from the years of 1988 to 1995.This needs nothing else but just replace your old computer and go.Nothing extra needed.This is suppose to give a extra 25 horse power to your engine.It would be great for that extra power when needed.

 

Hey just curious...... I have a 86 305 TPI Iroc im using for parts can I steal anything in ref to this TBI swap???? ECU? Knock sensors ect?

 

So I found a 454 TBI for sale here locally for $100 is this what you were telling me to buy??


Mike

 

You do not need a bigger TB for a 255FWHP 350 ci engine, I would save that $ for tuning equipment.

 

shouldn't I have it programmed and tuned after I install the 454 TBI.. the new 355 Vortec has a cam and was told it will produce 350HP

 

With 350hp a bigger TB is a good idea.

Fuel and tune in post #5, with 350hp the FP nubers will be bigger.

 

The vortec heads dont need special headers, standard SBC headers work. I run hooker shorteis, without airtubes. Ive had them bolted to a vortec headed 388 and now are bolted to my "temp" stockish 70s 305 from an el camino.