I was wondering what has to be done to switch a 305 TBI from a 91 RS to make it a 350 or have it bored to the 355...There are no aftermarket accessories on the car so it only running about 170 hp..With these bigger engines how much horsepower will I get and what kind of job needs to be done and for around how much.. Am i goin to need a new tranny and things like this? And one more thing everything would have to be done right bcause I have a 13 mo old son and his safety is big thing too

 

It's not possibel to "make a 305 into a 350", because the 305 bore is 3.736" and the 350 bore is 4.000". You can't bore a 305 block .264".

However, it's easy enough to just swap in a 350 short block. However, without attackking the bottlenecks in the surrounding parts, your new 350 will be as crippled as the 305 that's in there now.

What the car needs is an exhaust system, all the way from the heads to the street; a cam; and gears. If you do those three things, you might be surprised at how much better your 305 will run. Of course, you'd need to do those same things to get the full value out of a 350; otherwise a motor swao will be a disappointment.

------------------
"So many Mustangs, so little time..."
ICON Motorsports