MikeRWK

First off car is an 86 cutlass with a 305
Can i do this swap without using the tbi manifold?
I have 2 ecus to choose from 91 roadmaster 305 and 92 350 truck which should i go with?
What harnesses will work for these ecus?
Would L69 heads be good on this engine?

Here's some pics of the engine if it helps, i wont be getting it until saturday so these are all i have:

jim_in_dorris

Use the ECM and harness from the 91 roadmaster, and yes you can make the change by adding a carb to tbi adaptor which is readily available.

MikeRWK

Thanks, i know about the adapter but didnt know if maybe the tbi manifold had provisions for sensors that this one doesnt.

UnderCover89TBI

iTrader: (25)

Tbi manifolds have 1 sensor on them for the engine coolant temperature sensor. You should have a spot for that on your manifold. So should not be a problem. Welcome to TBI world. haha. If you do not know where to get the spacer. Summit, Jegs, CFM-tech. All offer them. The first two are probably cheaper. Good luck with your conversion.

MikeRWK

Thanks summit/jegs wont take my credit card because its canadian :S I own a 89 k1500 with 350 tbi atm but shes not worth fixin, im tradin it for the cutlass and some cash.

camaronewbie

Can I ask why swap to TBI? I'm just curious....

I mean all the trouble involved - it's not as easy as popping a TBI on top. You need a TBI fuel pump. Not sure if your car has a gas return line - TBI uses a return line back to the tank to regulate fuel pressure. The entire ECM and wiring swap - glad it's not me. Most everyone that has a factory EFI system (except maybe LS1 folks) wishes they could legally be carbed (of course this in the interest of going fast without chip programming). The quadrajet system is efficient, can handle alot of power and remain fuel efficient, and can't be beat for a carb. It would just be so much easier to stay carbed. A TBI system might gain you 10mpg on a perfect day over the carb - unless you are driving 100 miles a day I can't see the savings per dollar/trouble spent to switch.

UnderCover89TBI

iTrader: (25)

If it were me. I would buy the fast ez efi or holley efi that are self tuning and put that on and roll. instead of messing with it all.

dimented24x7

iTrader: (2)

The aftermarket systems are really expensive. I think for something like a stock 305 thats just going to be for driving the TBI system would be fine. So long as you use the stock TBI induction and manifold parts as well as a similar flat tappet cam, it will work fine with a stock chip and get you where you need to go for a lot less than a high $$$ aftermarket unit would.

dimented24x7

iTrader: (2)

Teh q-jet is probably the only carb I would ever consider running. But, it can never compare to a properly tuned FI system. The hard part with the FI is understanding how it works. Once you know that, its relatively straight forward.

As for this swap, its not as hard as you might think. For less than a few hundred dollars, this can be done by scrounging a wire harness and other items from something like an old L03 or L05 caprice.

UnderCover89TBI

iTrader: (25)

I agree for a relatively stock setup

MikeRWK

I want it for the mileage and im trading an old q-jet for an ecu, dist, and throttle body and i can get the rest really cheap.Parts are plentiful here the road salt rots the bodys off everything.the wiring is nothing for me i like wiring.

MikeRWK

is it possible that engine could be a 350 since it has the blue valve covers? i dont remember seeing any blue 305s

dimented24x7

iTrader: (2)

It could be, or it could be a rebuilt 305. The only way to know is to check the casting numbers at the rear of the block. Not an easy task on an old, grimy engine.

Fast355

iTrader: (2)

Plenty of BLUE 305 engines out there, every 305 built from about 76-82 should have been blue.

RFmaster

Use 305 ECM from 91 road master. A complete harness from B-body takes about 1 hour to extract intact at a local JY. You'll need EGR control valve, CTS, IAT, ESC, KS - also pull purge canister - on 91 it is controlled by ECM. It looks like you have a non CCC controlled HEI - vacuum advance. You'll have to either replace it with CCC HEI (a four circuit connector) instead of vacuum advance or find small hat HEI from a TBI truck or F-body with external coil. Depending on which one you get you'll have to replace matting connector on the harness side (or not). All of the above can be JY sourced for less than $150.

Fuel pump and return line will have to be installed.

Fast355 is correct - GM started painting engined from 77 onward blue. My 76 Chevy Malibu Classic must have been the last one with its 305 2bbl (federal) painted in Chevy Orange.

//RF

Fast355

iTrader: (2)

I would run a large cap HEI ESC from a CCC Q-Jet model or TPI model. The large coil-in cap distributors are better than the small cap junk in many ways.

1983 was the first year for a black painted 305 and my early production had blue paint under the black paint, go figure.

Street Lethal

iTrader: (16)

Quadrajet's are excellent carburetor's, and will perform just as good as any fuel injection setup when you know how to set them up, it's much more than just setting the idle mixture and fast idle screw(s) though. No O2 correction of course, but when you dial it in, you won't really need it. I hardly even use O2 correction myself in my chips, only at part throttle, as idle and wide open throttle are always in Open Loop. Not trying to tell you that the carb is better than the TBI system, however, when both setups are maximized, don't expect the TBI to be that much better, because it really isn't, so really consider your options. I'm running an L69 in my '84 Anniversary Trans Am, and the heads aren't that much better than the LG4's. If you didn't buy the heads yet, just stick with the stockers and open/clean them up to save you some money. Port match the intake manifold of your choice, then select a cam to fit your desired RPM range. Either way you go, TBI or carb will perform well for you, but remember that real performance is found in the cylinder heads. Good luck....