Hey everyone,

I'm going to be rebuilding or replacing the 305 in the next month in my Carbed84 T/A that has the CC Qjet on it. This isn't a carburetor question persay, so if this is the wrong forum for this, I apologize! I was wondering, since the TBI guys don't like carb guys asking questions, what, if any changes will I have to make to my ECM if I swap from the 305 to the 350?

Thanks in advance for any advice!

 

Since the ECM adjusts the air to fuel ratio from the information it gets from the o2 sensor, I doubt that you'll need to do anything. The quadrajet that comes on a 305 can definately flow enough for a 350.

 

What I had to change when I put the 350 under the stock 305 carb:

1) Adjust it to factory specs.

2) Drive and race it.

 

If it's a mild 350 combo (no big lumpy cam) the system will work just fine with no changes. Carbs don't know how big an engine is under them- they only know airflow.

 

Alright, well, based on this, then I don't have to do anything to the small ECM that's in the car currently and it'll run fine whether or not I rebuild the 305 or swap in a 350.

Damnable thing is if I want the 350, I'll have to drive from Utah back to New Mexico to get it so I don't have to buy another block...had to leave it in storage because I didn't have any room left to pack it!

 

It would probably cost less to buy another block than it would to drive from Utah to New Mexico and back to pick up the one you have. Unless you combine it with a trip for another purpose, of course.

My brother has a roller block 350 that he'll give me. Bad news is it's a 330 mile drive one-way, and the diesel truck would eat up $350 of fuel to go pick it up. That's an expensive shortblock.

 

I have a roller block, picked it up complete out of an 98 Silverado for 250...really wanted to use that block but didn't have the space to take it with when we moved to UT. So I guess I'll start looking for another motor. The 350 argument is starting to win me over.