SBC v. SBO

[86bluedemon]

So ive heard a lot of discussion about sbc v. sbo from a performance point of view...what are some opinions on the more practical side? I have a stock 307 with the shitty metric 200r 3SPD transmission. Now i not only need to know which would be more practical (cheaper in the long run, better on fuel, need durability and reliability as much as i need power), but also which combinations I can go with that will fit properly onto my car (which engine matched with which transmission-200r4 v. 700r4- also which transmission length goes with which engine, etc., etc.) I need the car to get decent gas mileage and be able to handle everyday driving as well as make a trip from Louisville to Chicago on a tank of gas (I used to drive a 2000 Cadillac SLS with 17-25mpg city/hwy Im pretty sure and that car could make the roughly 300mi. trip on about 3/4 tank, so that can serve as a benchmark). Since Im going to be trying to have a lot of this work done professionally and at one time, I really need to make sure I get this right. I hope I was specific enough.

Thanks

Also, I will be looking to put on a posi rear end either 7.5" or 8.5" or Ford 9"(whichever I can find) with, hopefully, 3.42 or 3.73 gears(GM) or 3.40-3.70(Ford).

 

[all4gss]

SBC is more practical all around. Cheaper to build, more build articles availble, etc. etc. You didn't mention if you were keeping a carb or going efi. A gmpp crate engine with a TBI set up would be a good middle of the road. A SBC and SBO will bolt to the same motor mounts on your frame. You will have to push back the cross member to mount the transmission if you're replacing the th200 with the 200r4. If your car is '84 or older you should already have the frame provisions to move the cross member.

This is all from memory on a project I did 10 years ago putting a 403 SBO in a 1984 cutlass that was originally equipped with a v6 buick. My only trouble was replacing the v6 frame mounts with v8 frame mounts.

let me know if I've messed up any of the details guys.

 

[dan2286]

As much as I hate putting Chevy engines into an Olds, my vote is a fuel injected LS engine. I am sure many people would recommend a carb instead of F.I., but it would be nice to see someone do something a little different. Not saying carbs are not reliable, but if you are going to be driving a lot, fuel injection would be better in the long run. That of course depends on how much money you have and how knowledgeable the person works on your car is. When you are looking for fuel mileage, you can't beat the modern technology that has been put into the LS engines. If you went with an Olds, I think it could be very hard to achieve great gas mileage with the outdated combustion chambers. It could be done, but it would take a lot of time and money.

 

[madmaxstyle]

If your going to do a swap the 350 does have a better power potential for $$ spent ratio.
Theres definitely cheaper bolt ons for the 350 than the olds
I personally think a 307 could be built to perform well as a daily driver with a little massaging. It would add cool factor to have a 307 olds that really performed well, because everyone and their neighbor nowadays has a Chevy 350. IMHO

 

[v8power]

If your going to do a swap the 350 does have a better power potential for $$ spent ratio.
Theres definitely cheaper bolt ons for the 350 than the olds
I personally think a 307 could be built to perform well as a daily driver with a little massaging. It would add cool factor to have a 307 olds that really performed well, because everyone and their neighbor nowadays has a Chevy 350. IMHO

making a 307 perform is a waste of money imo,

 

[dan2286]

If your going to do a swap the 350 does have a better power potential for $$ spent ratio.
Theres definitely cheaper bolt ons for the 350 than the olds
I personally think a 307 could be built to perform well as a daily driver with a little massaging. It would add cool factor to have a 307 olds that really performed well, because everyone and their neighbor nowadays has a Chevy 350. IMHO

making a 307 perform is a waste of money imo,

Not if you know what you're doing :wink:

 

[v8power]

well you can spend a bunch of money on it to make it...ahh better. but you can have a way better small block chevy dollar to dollar. unless you can prove me wrong.

 

[all4gss]

I second that. If you're keeping a SBO, which I would support, it just isn't the most economical choice, then ditch that 307 and put in a 71-72 350 (best heads) or a 78-79 403 (you'd want to replace the 403 heads).

The good news is everything on that 307 will bolt to other SBO engines so you just need a good long block to put in there.

I had a 403 with the Edelbrock Performer package in my cutlass and it was a great street engine. It's not a horsepower motor but the torque will move you around pretty quick anywhere in the power band. Mine even had the smog heads on it and it was a performer. With some 71-72 factory heads you could make some serious power=$$$. You'll wanna check out realoldspower.com if you decide to go the SBO route and you'll see first hand that for what the parts will cost you could buy a stout GMPP crate Chevy 350. On the best of days that 403 would get 16 mpg but it averaged 12-14 depending on driving style.

Also, keep in mind that if you get too carried away with the engine you're going to have to look for a strong ($$$) 200r4 to put in there. Basically one of the 200r4s that came in the 8.5" rearend cars. The other option is the 700. Either way don't forget to cost in a different drive shaft if you use a longer transmission.

 

[olds307 and 403]

The SBO will get better mileage, be more reliable and produce more torque than a comparable year SBC. The only way I would consider a SBC if it has Vortec or similar modern heads and fuel injection. The Olds was just a plain reliable, fuel efficient for it's time and lots more low end torque. The LS series is the modern way to go, I wasn't impressed with the 5.3 power compared to my mild TBI equipped Olds 350 powered 4X4. They shouldn't even be close, but the Olds might even out power that stock 5.3!

 

[v8power]

are you comparing this to a 305 chevy..if thats the case your better off with a 4.3