With the help of the information I read on this board I swapped out my 305 for a 350 in my 1991 RS. I purchased a 1992 caprice 9C1 former cook county forest preserve K-9 car with 69000 original miles. I removed the motors from both cars and put the 350 in the Camaro and I will be putting the 305 back in the caprice in order to sell it. There was very little differences with both motors as they are both TBI. I swapped the ECM's a couple of sensors and that was it! The 350 runs great with no check engine lights or codes thrown. Although the 350 is stock there is a noticable difference in the way the car drives and performs which has made the swap worthwile.

Thanks again to all that post here! Reading various posts made this swap go very smoothly.

 

Congrats on the swap. when you put the 350 into your RS, did you take the t-converter as well?

 

Any tips with the swap? I am contemplating whether to do a 350 tbi or 350 tpi swap.... Whichever is cheaper and easier (limited on both cash and time). My old 305 is getting tired, and its about time to put her to rest..... Did you have to do any extra wiring with the ECM swap?

 

You could swap from the 305 to a 350 TPI engine while keeping your TBI system which would make the swap much simpler with minimal headaches.

 

Here is the only concern I would have, even though it only has 69K miles on it, it was a K-9 car. That means the engine sat and idle with the air on for hours at a time. That is the equivalent of MANY thousands of miles more over the life of the car. I would do a compression test, leak down test, and check the timing chain for stretch just for insurance. Chances are everything is fine, but I would hate to see a stretched chain or problematic cylinder let go or something.

 

Checked compression, timing chain, etc. Replaced all of the tin gaskets motor runs strong. Biggest hurt was car sitting for severakl years undriven.

 

Thats good to hear i was going to do the same however i didnt think the 20hp increase from the lo3 to lo5 would be worth it? You may have changed my mind.

 

THe stock 305 in my Rs was 170 HP the Stock 9c1 350 is 210 HP. The difference is pleasantly noticable well worth the time. Next summer I will add headers and possibly refresh the motor.

 

What you are also not catching is the fact you are gaining 40-50 ft/lbs of torque from idle-redline. With the gearing and converters used in these cars that is HUGE! The car pulls harder from a stop or a roll.

 

I will be making the swap very soon however im going with carb, i know its going to drink the gas a little more, but hell i have the old school crager Ss's why not go with carb, and the good oh turbo350 trans oh yes.

 

So, Jono4820, all you had to replace was the ECM and a few sensors? If that's it, I may do this swap... Did you have to replace fuel pump, or anything else major? Is there anything you would recommend that I replace while doing the swap, or any tips for doing the actual swap?

 

I Had to change the Knock sensor, ECM (and chip), injectors, fan temp sensor,(donor car had clutch fan), Flywheel, and various mounting brackets. I did not change the fuel pump and the car runs just fine, but plan on replacing with a TPI one in the near future.(stock one is old and probably worn, TPI pump I am told will give more volume of fuel in case I am not getting enough) I would recommend getting two engine stands and putting both engines next to each other to swap out parts. I took detailed pictures of both engines before hand so as to not miss anything. I would replace water pump, oil pump, timing chain, gaskets, and put on headers when doing the swap if you can afford it. I could not afford headers at the time of my swap and I will be adding them next spring along with freshening up the motor.
Overall the swap was surprisingly simple and fun to do, more importantly it was well worth the time and energy!!

 

I probably won't be able to swing the headers, unless I wait until tax time... I think I might spend the money on a stroker kit to make it a 383... I will probably leave it at a 350 for now though... I am currently searching for donor cars...

What did you use from your L03 on your L05?

 

I used the TBI (with donor injectors), All of the belt driven accesories, electric fan thermostat, temp sensor, and all of the emissions parts. The only way one would know that I did the swap by looking at the motor is to run the numbers on the block, (which you cannot see) otherwise it looks identical to the 305. I did not change the set up or tuning of the 350 so, the 9C1 computer is set up perfectly as it was in the donor car. I did not have to burn 100's of chips to get a decent tune.

 

This sounds like the swap for me... Now I just have to find an engine to do the swap with.... Is the car's acceleration any better? And would I need to start shopping for a stronger rear after the swap? I have no clue what my lil' old stocker can handle...

 

Acceleration is much better. 305 motor had 170 HP with 255 lb-ft of torque 350 (9C1) has 205 HP with 300 lb-ft of torque. Improvement of 35 HP and 45 lb-ft of torque!
One would really have to build the chit out of a motor to hurt the trans or rear-end. If you can fine a 92 caprice 9C1 (police package) that is what I did and it worked great. Motor will need freshening....no big deal. HEre is what I spent. 92 Caprice 9C1 on Ebay 861.00 parts for the swap around 300.00. I resold the Caprice with the 305 in it instead of the 350 for 1000.00. My ballpark out of pocket cost for the swap was a little more than 100 bucks! I still will have to spend money to freshen the motor in the spring however, not a big deal as I will do all of the work my self...

 

I'm probably going to have to go to a U-Pull it parts place like LKQ... The only caprices for sale around here have the big a** 2_" rims and ride higher than a fully lifted F250.... I can get a full engine from LKQ for $300+ and the computer for about $35.... I might be able to find something with headers on it.... Never know what you'll find in a place like that.... Of course I'll have to buy a gasket set, and some other typical replacement parts, but it'd be worth it I think...

You got a really good deal... What is your future build plan looking like? I want a strong street car (350-400rwhp), that can still be my daily driver (I live about ten minutes from my job), and have fun with on weekends....