71 350 Conv. Resto. Keep matching #'s 350 or Get 455?

If I rebuilt my stock '70 350 (8.5:1 compression) to stock '70 specs (10.5:1 compression, I think), how much additional HP does that buy?

Thanks

 

Most certainly. All cars are affected by this, no matter the size. As a rule, you want as much of the engine (weight) behind the upper control arms (closer to the firewall) as you can get. The physical dimensions of the engine bay and distance between the firewall and engine mount location (as well as the physical dimensions of the engine itself) will be your main limiting factor.

This makes the Buick 350 (as well as the Buick v6, which is even shorter) an ideal candidate for cars built for handling, rather than maximizing engine displacement for straight-line performance.

My 2c

 

Results will vary, but my sources indicate an increase of around 25-30 numbers on both hp and torque, give or take. This is going from 8.5:1 static (6.5:1 dynamic) to 10.25:1 static (7.75:1 dynamic) with the exact same OEM blueprinted engine specs.

 

Sounds appealing, but I'm having a little big block envy at the moment. Although, I've never actually driven a big block car.

Thanks

 

Nice. Can a Buick 350, built to stock '70 specs, run on pump gas without any detonation issues?

Thanks

 

Yes. At sea level, 93 octane is safe to run with the Buick 350's combustion chamber size for DCR's between 7.25:1 to 7.75:1, with 7.5:1 the 'ideal safe zone'. This is at sea level, where atmospheric pressure is highest. Greater elevations will make the DCR's stated above even safer.

With the OEM cam (or a performance cam with similar IVC point) will sit between 71* and 75* IVC point, making static compression ratios of 10:1-10.33:1 or so safe to use with combustion chambers in good shape and proper timing.

This is considering an ambient engine temperature between 180-195 Fahrenheit and all iron componentry.

 

Once you have gone big block, you never look back.

 

The hp differences are nothing compared to the torque increases. It makes it a different animal.
I've always been able to tune much better mileage by going to bigger cubes, the factory advance curves leave much to be desired.
It's not worth computing tiny differences in compression over factory specs and try to equate that into torque or power estimates.

 

Big blocks are monsters. You have to be very careful when first driving one until you get used to it. They can get you into more trouble and get you killed if you're not familiar with them, especially in lighter cars.

Know your (and your car's) limitations, and be safe! There's more than one way to have fun in a car without taking off like you were shot out of a cannon.

 

I can respect this statement, as I have gone down both paths, and I have looked back.

If you hunger for more and more, then sure. I like to weigh the pros and cons of everything though.

 

It's all relative, and going from low compression to higher compression makes more than just a little difference when both are tuned optimally.

There IS such a thing as too much. This is subjective and relates to individual interpretation and preference, of course.

Though when you start adding big power to cars, much more has to be considered for the rest of the vehicle, such as suspension, traction, etc. depending on what one intends on using it for.

 

Well if you throw the "stock" BS out the window and build a sbb 350 stroker to 370 to 390 cid then you'll have your cake and be able to eat it too. Increased low end torque, increased HP, increased RPM capability, shorter engine to help keep weigh closer in middle of car. Swap on an aluminum intake and even lighter yet, then there is the sbb 350 heads that TA is supposedly working on to release over the holidays that will help make that stroker engine even more of a BEAST! That would weigh in under 400 lbs, probably around 360 to 380 lbs!



Derek

 

I look back all the time,....when owning a BBB you look back in your side and rearview mirror at all the people that didn't have enough

 

Nothing wrong with a nicely built 350... Some head porting, 212 cam, and it will run well and look stock. Or get the alum 350 heads that are coming out in a month or so and you can get some serious gains.

 

Coming from the man with many

 

I agree.

I have a 2013 Dodge Challenger SRT8 that's obscenely fast. This is why I'm reluctant to alter my matching #'s '71 GS 350, even though it's a lowly base model.

Thanks

 

Or with a car built for something other than driving it 1/4 mile at a time, you could look back at the gas station you just passed, or at those winds and twists you just ate up instead of the ditch, etc. "Enough" of one tends to mean giving up 'enough' of another.

There's always more than one point of view.

Whatever floats yer boat.

 

Why give up anything? Have your cake and eat it too!