I own a 91 Z28 with a 305 at the moment. Everything is stock on my vehicle except my exhaust, I have a cat back borla system.
I need a new engine, due to costs, im likely going to purchase a rebuilt 305. Since the engine wont be installed, i figure now would be the best time to modify it since it will be easily accessible.
I want to make some upgrades, nothing too crazy. I would like to do enough so that im going to feel the difference from what i have now.
I dont know too much about cars, what are some good upgrades i can make that wont be too much work or overly expensive. Id like to get the car back on the road asap.

 

IMO rather than modyfying a rebuilt 305 it would be more effective to replace the old 305 with a rebuilt 350. The cost would be about the same, and either way you need to reprogram the PCM to account for mods.

 

I thought about replacing my 305 with a 350 but i have a few concerns. To the best of my knowledge, the 91 z28 did not come with a 350, so will i be able to just pop it in my car and replace the old engine without any modification or am i going to have to make new engine mounts an start welding? The other thing is, from the websites ive found, there is only a 15hp difference between my engine and the 350, the 350 however has more torque. My concern with that is, will my rear end be strong enough to handle a 350 the way it is? I just want to replace the engine and leave everything else stock.

 

The main difference is bigger pistons ( bore ), Same stroke, same externals, etc. Make sure that You get a 350 from '88-up so it has the one piece rear main seal, that way it'll be a bolt in. You can even use Your 305 flywheel. Believe Me, it has a whole lot more than 15 extra horsepower, I don't care how They're rated. It'll have at least 50 more horsepower, probably more.

 

they are made from the same block so you will be able to just bolt it up (as with any small block) to your old mounts. you say the combo your looking at is only 15HP difference but you say it has more torque. the torque is what you feel when you step on the gas, the HP is what keeps you going so you I'm sure you will like the difference. your rearend will hold up the same because we aren't talking huge differences in power here.

no matter what path you take, you cpu is going to be your biggest change

 

What is involved with changing a cpu and how much does it cost?

 

You can go to a place like PCM for less, and they will send a properly tuned PCM for your mods on an exchange basis. Check their website. www.pcmforless.com

 

i just want to be sure i got all of this. What you guys are saying is that if i just replace my 305 with a 350, other than the cpu i shouldnt have to upgrade anything else? The 350 will bolt right in place of the 305 with no modification of any means. The transmission i have will also work fine with a 350? Is that all correct?

 

yup yup

 

one thing that wasn't mentioned is if you go with a carbed motor and a standard hei ditributor you don't have to worry about the pcm. all it will be needed for is to lockup the torque converter that is assuming you have an automatic transmission. the carbed engine is gonna cost you ALOT less than the injected one and they are much simpler to modify and work on. Sick