Which is better for high performance / durability / parts? 263 or 320?

[Untame]

I'm looking at picking up a str8 for a special high-performance project. I've heard that the 320 is "quite a bit" heavier, but I don't actually know the long-block weights of either. Also, I've seen modern bearings on Ebay for the 320, but not for the 263. But RockAuto has head gaskets for the 263 but not the 320. Are pistons available? Etc.

What about camshafts? Is there an aftermarket? Are there factory replacements available for cores?

Because my project involves an proprietary head design I'm only interested in the engine from the deck down. How are they different, and which one is "better" for a high performance (possibly forced induction) build?

Some information that would be helpful would be piston profile (dish or flat? valve reliefs? how many total CCs?) and piston to deck clearance.

I actually work for a car builder, and we might be able to bring something spectacular to the market in the form of a high-performance head. You help is appreciated, and the Buick Straight 8 community could benefit greatly a couple years from now.

If you were going to develop a serious performance Straight 8, would you start with a 263 or a 320 block/rotating assembly?

[bob k. mando]

tons of info in this thread:
http://www.teambuick.com/forums/show...s&daysprune=-1

saltcat has a thread on his Bonneville car someplace.

the reference page has several articles on straight 8's. here's cross sections of a 263 head:
http://www.teambuick.com/forums/view...ead_x_sections

[Buick Guy]

Lots of pictures and video. Look on YouTube and Facebook. Salt Cat Racing. Nothing is available on the after market for high Performance. There are lots of companies, however, that will build what you need to make lots of horsepower with the Buick straight 8. As we have found, it only takes money. Welcome to the world of obscure engines. Come to Bonneville in August and visit us in the pits. You can't miss the 1951 Spartin Aircraft trailer that is home to Salt Cat ll.
Doug

[Untame]

Lots of pictures and video. Look on YouTube and Facebook. Salt Cat Racing. Nothing is available on the after market for high Performance. There are lots of companies, however, that will build what you need to make lots of horsepower with the Buick straight 8. As we have found, it only takes money. Welcome to the world of obscure engines. Come to Bonneville in August and visit us in the pits. You can't miss the 1951 Spartin Aircraft trailer that is home to Salt Cat ll.
Doug

Thanks, Doug! I've seen some of the Salt Cat stuff. We're going a different direction. Money isn't an issue for us. And like I said, I only care about the engine from the deck down. So which block gives me the most to work with as far as repair parts (modern bearings, aftermarket pistons, aftermarket camshafts, etc.) and the strongest bottom end? And is the weight difference substantial?

[raycow]

I'm looking at picking up a str8 for a special high-performance project. I've heard that the 320 is "quite a bit" heavier, but I don't actually know the long-block weights of either.

If you were going to develop a serious performance Straight 8, would you start with a 263 or a 320 block/rotating assembly?

According to the 52 shop manual, the 263 weighs 746-749 pounds and the 320 weighs 833 pounds. Since both engines are generally similar in design, I would start with the 320 and expect it to deliver roughly 20% more power than the 263 for the same amount of $ invested.

When you say "serious performance", does that mean you are planning on some kind of crossflow hemi head to get decently large valves?

Ray

[Untame]

According to the 52 shop manual, the 263 weighs 746-749 pounds and the 320 weighs 833 pounds. Since both engines are generally similar in design, I would start with the 320 and expect it to deliver roughly 20% more power than the 263 for the same amount of $ invested.

When you say "serious performance", does that mean you are planning on some kind of crossflow hemi head to get decently large valves?

Ray

Thanks, Ray. The 263 is not as much lighter as I was hoping, so I think you're right -- the 320.

You're thinking down the right path on the head, but I'm not at liberty to discuss the specifics on our project. It includes some rather unusual features. But let's just say we aren't holding anything back.

Any tips on building the bottom end of the 320 to handle a lot of power? Any opinions on the aftermarket insert bearings I see on Ebay?

[Untame]

So... I've found three local junk yard Buicks with Str8s. Which years/models would have the 320, and how do I tell the difference most easily?

[JR9162]

Probably 49 to 52... to ensure you got one with insert bearings. Be sure to sonic test your block after acid dipping it to ascertain if there's core shift and thin cylinder walls from corrosion in the water jackets. I'm using a 263... It's a more recent design, but the 320 will afford more displacement.

[Jyrki]

So... I've found three local junk yard Buicks with Str8s. Which years/models would have the 320, and how do I tell the difference most easily?

You'd be looking for the Roadmaster. The Century and Limited also carried the big block, but weren't around anymore by 1949.

[Jyrki]

I'm looking at picking up a str8 for a special high-performance project. I've heard that the 320 is "quite a bit" heavier, but I don't actually know the long-block weights of either. Also, I've seen modern bearings on Ebay for the 320, but not for the 263. But RockAuto has head gaskets for the 263 but not the 320. Are pistons available? Etc.

What about camshafts? Is there an aftermarket? Are there factory replacements available for cores?

Because my project involves an proprietary head design I'm only interested in the engine from the deck down. How are they different, and which one is "better" for a high performance (possibly forced induction) build?

Some information that would be helpful would be piston profile (dish or flat? valve reliefs? how many total CCs?) and piston to deck clearance.

I actually work for a car builder, and we might be able to bring something spectacular to the market in the form of a high-performance head. You help is appreciated, and the Buick Straight 8 community could benefit greatly a couple years from now.

If you were going to develop a serious performance Straight 8, would you start with a 263 or a 320 block/rotating assembly?

You can find most everything from Bob's Automobilia, but some aftermarket engine components are off-shore crap. Camshafts aren't available, but you have a performance regrind by American Custom Cam or Elgin.

The stock 320 crank and rods are good for 600+ HP, according to Gerry Duttweiler. You can reach these numbers by super/turbocharging. The first item to let go is usually the #2 main cap - avoid excessive low-rpm torque (roots charger) and excessive compression ratio. Pioneers like Chuck/Gary Hamann and Gerry Duttweiler have revved the stock crank/rod combo past 7000 rpm and survived, though 5500 rpm is considered the safe red line.

The stock "turbulator" popup pistons are no good. You must get custom pistons made for you. Folks have used Ross and JE among others. 3.875" is considered the maximum overbore on a good core.

Convert the oiling system to a full-filtered system. The cooling system should be modified as well, to enter the block at the middlemost freeze plug.

The Olds 455 balancer can be fitted on the Buick crank pretty easily, as can the LS Chevy balancer, I hear.

You can get copper head gaskets with or w/o integral O-rings from Gerry Duttweiler in Ventura CA, phone 805-639-0237. Say hello from Jyrki