bitty9

I have a 1983 98 and the little 307 seems to have croaked. Large knocking coming from inside. Anyway, I'm planning on replacing it with something larger. Not sure what size I'm looking for, but anything that will bolt into place without a whole lot of changes. I believe I have the 200 4R trans(might be 200 metric, not certain). Guess I'm looking for suggestions of what engines may fit, and is there anyone with one in good condition for sale at a decent price.

henryk8398

This has been widely discussed and is a very easy bolt-in swap. All Oldsmobile V8 engines from 1964-1990 are externally identical and will bolt into place of the 307. The most common swaps are the SBO 350 or SBO 403. With those engines, you can keep the computer and enjoy almost the same gas mileage and basically double your horsepower! A 455 is a great swap if you don't have to worry about emissions. The big car will love it! The 455 is a little taller, so beware of hood clearance. It shouldn't be a problem on a full-sized car. There are plenty of G-Bodies with 455s. Other engines include the 400 or 425. Even a 330 would work and be a HUGE improvement over the 307. Basically, swap the long block and use the 307 accessories, including the water pump.

You will need to rebuild and modify your 200-4r to live behind a bigger motor. It won't last long behind a 403 or 455. It would be marginal behind a stock SBO 350. To figure out what you need to do to the trans, I would encourage you to search the forums for "350 swap","403 swap", or ""455 swap". It has also been well-documented.

Read this, too:

http://www.442.com/oldsfaq/ofswp.htm#Swapping

Good luck! I plan to do the same swap in the next few years when my 307 dies. It's running great right now, but it's tired. I found a 1971 350 out of a cutlass in a salvage yard last year. Check salvage yards in your area. Sometimes they still get big GM cars from the 70s. Craigslist, swap meets, and the for sale ads here are a good place to start. If you don't have a few thousand for an overhaul, try to buy a cheap, running car and take what you need! Make sure you check the casting numbers so you know what you've got!

droptopron

All Oldsmobile V8 engines from 1964-1990 are externally identical
All small blocks are externally identical - as mentioned big blocks have a taller deck height. It would give you more of an issue with getting your exhaust to bolt up rather than hood clearance. If you have three forward speeds its a Metric 200, four its a 200R4. A 350 or a 403 would be an easy swap but the metric 200 isn't the stoutest unit ever made. Be careful putting too much power thru it.