I have a 84 olds 98 w a 307 and I was thinking about swapping it out for something with more power. There is a 78 delta 88 w a running 350 for sale near me for 500 bucks would it be worth it to buy it? I’d wanna build the motor a little to make like 300 hp nothin too crazy cause it’s for a 98. I know 77-80 is a “windowed” main block. Should I just wait to find an earlier 350?

 

Unless you are going for high torque and high RPM, the late 350 will be more than enough to build for your 98.

 

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Ninety Eights routinely had 300+ conservatively rated horsepower from late 50s thru 1970. Just sayin'...

 

The 1977-up Olds 350s have windowed main webs and crappy heads. The 200-4R trans in your 84 will require internal modifications to live behind even a mild 350.

 

I had a 84 Ninety-Eight about twenty years ago and swapped in a 77 350 from my wife’s Cutlass that had 95,000 miles. Direct bolt in. I got another 100,000 miles out of the Engine.

 

As said the late 350 isn't a great motor to build. The 3A heads have a horrible exhaust port as well as bring crack prone. The windowed block can take less of an overbore as well. It is rated at 170 hp and 270 ft/lbs stock.

 

Why set up an HP goal? It will be improvement no matter what. Change some mild cam to it, some intake if you like and be done with it. Goes way better with the nature of big car.
You wont be racing it anyways i believe.

In that use that motor would do more than better. Scrap the car for parts and sell them, if theres anything usable, and recoup some of the cost that way. You might end up with a "free" motor, who knows.

 

When I said 300 hp I just meant I’m not tryin to build a loped out 500 horse race motor to
throw in a 98

i would have to trans I could swap into the car too I’d probably have to change the rear end gearing tho

I could probably sell the ralley wheels and scrap the car out and end up with a free motor is why I thought about doing this in the first place

would the windowed block sustain a .030 bore if I had to bore it?

 

Yes, I believe the later 350 can .060" without issue. The 76 and earlier 350's can go .100"+ over in most cases. If there are parts for your car with the motor, that makes it more tempting for $500. Figure on small dish pistons with those heads in a build up, they should be around 75cc. Do a compression test and put a oil pressure gauge on it. You never know, it may be in very good shape as is, it may just need gaskets and a timing chain.