Hey there,

I was toying with the idea to replace my 4.3l with a 350. I have a 1996 Blazer LT, 4wd, its real nice. I can't beat what I've got. With the 4.3l, I get 22 city 26 hwy. But I had a bit of an issue while driving across state.

I first noticed it passing through a small town, at a red light. As I sat, my Check Gauges light popped on and off. I checked the gauges and sure enough I didn't have any oil pressure.

I pulled off the side of the road to check the oil and noticed that I was so low that only about 1/8" registered on the dipstick. Not only that, but as I was sitting idle, I heard an engine knock.

I filled it up with oil and it drives fine, but I am thinking that the engine will require work soon. So, I thought about replacing it with a 350.

For those that have done the swap, what's your mileage like? If it's terrible (keep in mind I am getting 22/26), I was thinking about dropping a 4.8 into it. Not sure if that's even possible.

Thanks for all the information!

 

Odds are that your mileage is going to drop depending on what is done to the 350. If you just drop in a Vortec out of a mid 90's truck you might be able to pull off milage that is pretty close to what you are running now. The V6 converter is going to cost you though unless you swap that as well. People run the S10 converters behind V8s because it'll slip more and you get higher RPMs off the line this equals lower mileage.

So I would think that with a torque converter change while you are doing the engine swap, you could probably get the same mileage out of it. Keep in mind you'd want to stick with EFI(unless you're a carb wizard) and keep your foot out of the gas.