I need to rebuild the 350 in my 72 vista (69/70 with#6 heads) or put in a 72 455 4bl with ga heads and earlier small dish pistons the question is how will the gas mileage be affected in a wagon sb vs bb? i haven't driven it with either engine so i don't know what to expect. just want a daily driver. i think it may be a wash considering the vista's weight. any opinions appreciated . thanks

 

I would do the 455 since it has so much more torque and will get that wagon rolling a lot easier.

 

Yeah i just got the 455 running again don't remember why i removed the power brake line plug that was on it but after two days of messing with it distributors, coil, fuel pump finally got it running enough to discover the vacuum leak. idles smooth again so it definitely is a possibility. guess I'll put it in as i have it and only needs exhaust work but would still like any opinions on cost of running one verses the other

 

I would think the lower fuel economy would be outweighed by the awe factor of the BBO.

 

I don't have any first-hand experience with a 455 but one of the guys in the local club had a '70 SX that he said got 12 mpg, which is the same as I got with my 350. It mostly depends upon how you drive, though.

 

I look at it different. If you are looking for a gas mileage car. Buy a later model Olds Ciera or something like that. Otherwise put in the big block and who cars what it gets. Drive it and enjoy it. I don't put enough fuel threw my 442 a year to worry about what MPG is. Plus the pleasure is worth it.

 

I debated this same question before I built my new engine for my Cutlass. I decided to stay with the SB mainly for gas milage, but also so I didn't have to change as many things like exhaust system, cooling system, coil springs to accommodate it.
I use this car as a driver and it has worked out real well, I also added a OD transmission and a 3:90 gear. This combo works great together has tons of git up and go and still gets about 20MPG.

 

thanks for all the input the cheapest and quickest way seems to be switching motors for now. i will still have the sb to build if needed. its been a long road to get the vista to this point, so i would like to get some use out of it, in 8 years i've had it it's been driven less that five miles

 

I know the feeling. After 7 years working on my 60 Impala 2 door hardtop, it still wasn't ready. A guy offered me decent coin and I kissed it goodbye, even though I really liked it. My latest 65 442 is only 2 years now, and I already suspect if someone comes by with a pocket full of loot, it'll go the route of the Impala.

 

Just my thoughts, but for a street car the exhaust system on a 350 would be acceptable for a mild 455, and the BBO weighs 70lbs or so more than the SBO so the springs would not need to be changed. Cooling system may depend upon what your car currently has and your location.

 

Seems to me the exhaust maifolds don't fit. The 455 will be from a larger car and the manifolds may hit the frame. You might have to find a set from a 442, or run headers like they did on my current project.
As for cooling, most of my Olds's seemed to come with 2 core rads and run a little warm. The Vista likely has A/C and want's at least a 3 or 4 core with a 455. With my 442, a previous owner had a 455 put in it and felt the need for a 4 core Harrison. It sits fairly high, too, so I'm guessing they re-sprung it.

 

Thanks all, i just picked up a set of w/x manifolds threads are toast but they can be made to work and i do have the heavy duty radiator for a/c. Drove it around yesterday and if i didn't think the lower end was bad i would never change over to the 455. 350 seems up to the task for normal driving. What makes me think there is a problem is that when i advance the timing it has a rod knock put the timing back to the correct mark and noise is gone never had this experience before but maybe i never heard one at this stage before. Usually rod knock stays no matter the distributor position but this may be just a early stage, don't know but there's only one way to find out

 

NOT ROD KNOCK - pinging from todays crap gas!
Find some race gas or octane booster, and prove it to yourself!
Rod knock doesn't go away, once started, can only get worse.

 

In reply to Rickman thanks for the suggestion it couldn't hurt to try but it's at idle and only one cylinder i also can still feel the knock even though quiet at proper timing .i think with more running, timing won't be a factor i would be very happy if the problem is only from bad gas.

 

Hey Mike,
What ever became of the engine swap dilemma? Did you ever pick a direction and run with it, or still pondering?
Enquiring minds need to know. That rod knock getting worse?
Dave

 

After all the indecision i couldn't pass on a 350 found on Craigslist. Just finished
the engine swap its a 68 block with 7a heads was in a 49 chev pickup that the owner wanted to convert back to chev, rebuilt at one time has degree marks stamped on the flywheel to index a cam must be a rv type as idle is stock anyway the price was $200 and sounds great but it was a gamble. Also installed a Pypes ss system 2.5" with x connection and head pipes for a bb as they do not make sbo down pipes the only problem is the smaller driver side manifold port will not seal. the simple fix is to cut your old crossover flare 2-3" and use that as an insert inside the new pypes down pipe and you are good to go no leaks no welding. If needed any muffler shop could make a new piece for you but i liked the idea of using what i had .
The old 350, once on the floor i removed the valve cover an it was full of sludge i could not see how oil could drain from the heads if any got through the push rods i've never seen one this bad and it ran with no noise if kept in time. when i got it i changed the oil and filter and let it sit for 5 years only starting a few times but it is a early block with 6 heads so worth storing.
The 455 will stay in the 67 as it will be more fun there and i plan on getting the same pypes system from summit as i have the 442 manifolds ready to install.
That's where i am for now, i thought the head pipe fix was great if i do say so and hope it helps other sbo people who want to run oem manifolds