4.3 fuel injected to 305

[montekels86]

hey hows everybody doing im looking for a soultion with my montecarlo

ok i have the 4.3l v6 the problem is the engine has some problems from overheating it one night by mistake it rides kinda ruff and the inside has alot of build up in it..i did a tune up n the machanic told me it wasnt going to last me a year so by the way prices are today on rebuilding an engine i thought i rather swap it for another one

i was looking at the 305's but i want to know do i have to change my computer or any wires because mines is for the fuel injected one....i know it will bolt right up to the transmission what are the things that i will have to change in order to use that engine or is it better to just find another 4.3 n swap that into it

 

[86Cutlass383SR]

It's going to take a few questions to really zero in on a specific answer. Do you have to pass emission testing? Are you wanting to go with fuel injection on the 305, run the computer comtrolled carb and distributor, or remove the computer controls altogether?

I think the 4.3 uses the same frame mounts as the 305 so you should be good there. You said you thought you could reuse the transmission. Make sure the V6 transmission can hold up. It may or may not. I'm not really up on what trans the V6 had and if they had differant internals than the V8 version. Since the frame mounts are the same and you can use the transmission, then the driveshaft should be good to go too.

If you decide to go carb on the 305, then you'll have to get a differant float assembly for the gas tank. If you go TBI or TPI then you can reuse the float assembly with the correct in-tank fuel pump. TBI uses 15 psi pressure and TPI (or multi-port injection) uses about 45 psi. Carbs use around 6-7 psi.

The exhaust may need to be upgraded and probably the front coil springs, too due to the 305's weight increase from the 4.3.

 

[montekels86]

yes i need to pass the emissions test the transmission i have now is a 4 speed with overdrive i did a search n it can go with the 305
if i wanted to make the 305 a fuel injected insted of carb would i be able to take the fuel injected system from my 4.3

 

[flip66]

you will need new injectors, new computer, and a new fuel pump (might be able to use the 4.3 stock fuel pump on stock 305) you should be able to get it out of any F body (camaro firebird) with TBI. The wiring will be really close if not the same just make sure you have a diagram for both. I have TBI on a 350 in my car it works really well but I am using parts out of a 91 chevy truck. You will probably need a bigger radiator new mounts and exhaust work.

 

[HighwayJunkie]

What year is your 4.3 Monte? Mine is a 1987 and its a Throttle Body Injected engine, which is a 305 TBI with two cyls chopped off. If you have a 4.3 TBI then you can reuse the fuel pump, its in tank, and the 305 TBI out of a camaro should bolt right up. My car is getting a 305 TBI when my 4.3 with 87k finally dies.

 

[montekels86]

my monte is a 86 i believe im just gunna try to find me a 4.3 motor again cuz if i have to basically swap about everything in the front y even bother but it would be nice to have a 305

 

[86Cutlass383SR]

If you're staying with the TBI then I'd got to the 305. Other than the engine swap which will be easy, all you'll need is a differant chip (because of the higher fuel flow of the 305) and bigger injectors. Even your old pulleys will swap to the 305. This would be an easy swap and shouldn't be passed up!

 

[custom442]

4.3 FTW! I love that engine, set it up with some steep gearing and a manual and it'll be tons of fun. If you want to get crazy, a 2,500$ s/c kit, or build your own sy/ty set up for about twice that price. I vote another 4.3.