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

[pmuller9]

You're making me think, Jyrki...

Are there any differences between the deck surface of the 320 and the 248?

Also... I've been wondering if any has tried mixing and matching parts on the str8ts (cranks, rods, heads).

Having been through this design exercise once with the 263, I can tell you that starting with the 320 will be a whole lot easier.
There are 22 head bolts to design around and there is a lot more room between head bolts on the 320.

Might I suggest as you continue your hunt for engines, you get a 320, 263 and a 248.
When you pick up an engine get the cylinder head with it because I found there was a lot of information I needed from the stock head that helped in the design of a new head.

After you complete the 320 design then you can re-dimension for the small block.
The 248 and the 263 may be able to use the same head and is the reason why I recommended getting both engines.
You will be able to check parts interchange first hand

Good Hunting

Paul

[Jyrki]

You're making me think, Jyrki...

Are there any differences between the deck surface of the 320 and the 248?

Also... I've been wondering if any has tried mixing and matching parts on the str8ts (cranks, rods, heads).

I'm not sure what you mean about deck surface differences? The 320 block is about 5 inches longer than the smaller engines - nothing's the same

Nothing is interchangeable between all three engines except for valve lifters and distributor. I'm not entirely sure if the head is interchangeable between 263 and 248? "Alleycat" sure knows if it is or not. Cranks, rods, pistons - not interchangeable between any engine

One more thing to remember: transmission adapters exist for the 320 - Bendtsen's sells an adapter to mate any GM automatic or manual trans. Duttweiler offers an adapter for a Ford C4 automatic

[alleycat]

Yup, 263 and 248 heads are one & the same. There are differences in the decks that are worth noting. The bolt holes are in the same place on both engines (obviously) but the cylinders are not. The 248 cylinders are "pulled" togather in pairs, 2 pairs in the front 2 pairs in the back, with a patch of deck over the center main which divides the engine into basicly 2 4cylinder engines back to back. The 320 is exactly the same. These offset cylinders mean that the bores don't sit concentric with the cumbustion chambers, and the cylinders are smaller than the chambers, leaving a ledge around the perimeter. As pmuller said, getting bigger valves into a small bore without shrouding can be tricky. And, he is spot on about a small chamber and a flattop or dished piston. The 263 has equally spaced cylinders concentric with the chambers along with a bigger bore. With a bore out along with the possiability of a head with smaller chambers, a actual quench and majorly reduced shrouding is a possiability. But there's more! With the cylinders relocated, the head bolt threads are in bosses tied into both the deck and the cylinder walls and are blind. In the 248 and 320 one side the threads are through the deck intyo water and the other side is in the outside wall and part of the cylinder. Even with a deck plate there is almost no way the 248 or 320 walls will stay round. The 263 will. The 263 has a shorter deck height, making the cylinders more ridgid. The 263 also will handle 11 to 1 comp, possiably more, but it's impossiable to get it there with a stock head. The main bearing supports have more metal in them. 4-bolt main caps with the outer bolts angled into the webs would make the bottom end nearly indestructable. With a serious top end in place, I don't even know what this engine would be capable of, but it'd sure be intresting. Alleycat

[Buick Guy]

Damn, You've convinced me. Put it together and bring it to the "Great White Dyno". I guess I'd have to give cubic inches the edge.
Doug

[Untame]

Yup, 263 and 248 heads are one & the same. There are differences in the decks that are worth noting. The bolt holes are in the same place on both engines (obviously) but the cylinders are not. The 248 cylinders are "pulled" togather in pairs, 2 pairs in the front 2 pairs in the back, with a patch of deck over the center main which divides the engine into basicly 2 4cylinder engines back to back. The 320 is exactly the same. These offset cylinders mean that the bores don't sit concentric with the cumbustion chambers, and the cylinders are smaller than the chambers, leaving a ledge around the perimeter. As pmuller said, getting bigger valves into a small bore without shrouding can be tricky. And, he is spot on about a small chamber and a flattop or dished piston. The 263 has equally spaced cylinders concentric with the chambers along with a bigger bore. With a bore out along with the possiability of a head with smaller chambers, a actual quench and majorly reduced shrouding is a possiability. But there's more! With the cylinders relocated, the head bolt threads are in bosses tied into both the deck and the cylinder walls and are blind. In the 248 and 320 one side the threads are through the deck intyo water and the other side is in the outside wall and part of the cylinder. Even with a deck plate there is almost no way the 248 or 320 walls will stay round. The 263 will. The 263 has a shorter deck height, making the cylinders more ridgid. The 263 also will handle 11 to 1 comp, possiably more, but it's impossiable to get it there with a stock head. The main bearing supports have more metal in them. 4-bolt main caps with the outer bolts angled into the webs would make the bottom end nearly indestructable. With a serious top end in place, I don't even know what this engine would be capable of, but it'd sure be intresting. Alleycat

Thanks, Alleycat! The 4-bolt mains are be part of the plan.

We are going all the way with it -- farther than anyone in this thread has even yet begun to speculate. I guarantee when we get done with it you will hear about us.

Does anyone here have a CAD drawing of the stock 263 head gasket? If not, can someone tell me if the head bolts are symmetrical from one side to the other? (Are they placed on either side of the cylinders in the same location relative to the bore?)

[Untame]

I'm not sure what you mean about deck surface differences? The 320 block is about 5 inches longer than the smaller engines - nothing's the same

Nothing is interchangeable between all three engines except for valve lifters and distributor. I'm not entirely sure if the head is interchangeable between 263 and 248? "Alleycat" sure knows if it is or not. Cranks, rods, pistons - not interchangeable between any engine

One more thing to remember: transmission adapters exist for the 320 - Bendtsen's sells an adapter to mate any GM automatic or manual trans. Duttweiler offers an adapter for a Ford C4 automatic

Sorry... I meant to say "263 and 248."

[Untame]

Damn, You've convinced me. Put it together and bring it to the "Great White Dyno".

It's on the table.

[Untame]

BTW... we're looking to pick up a 263 in the next 1-2 weeks. Does anyone in the Wisconsin, Minnesota, Iowa, or Illinois area have one for sale? We don't need the transmission. Just an engine that is still loose.

[JR9162]

BTW... we're looking to pick up a 263 in the next 1-2 weeks. Does anyone in the Wisconsin, Minnesota, Iowa, or Illinois area have one for sale? We don't need the transmission. Just an engine that is still loose.

This guy says he has one, let him know I sent you... I'm JR9162 on the H.A.M.B. http://jalopyjournal.com/forum/showt...ighlight=buick

Call Rick at 586-255-9703, he's in Michigan.

John

[pmuller9]

Does anyone here have a CAD drawing of the stock 263 head gasket? If not, can someone tell me if the head bolts are symmetrical from one side to the other? (Are they placed on either side of the cylinders in the same location relative to the bore?)

The row of 9 bolts that are on the lifter side of the block,
the bolts that are on either end are not on the same center as the 7 bolts between them.
The front bolt is .055" closer to the cylinder and the rear bolt is .070" closer

Otherwise the 2 rows of head bolts are exactly 4.00" apart with the cylinder bore centers exactly in between at 2.00"

Bore spacing between cylinder numbers:

1-2 = 3.725"
2-3 = 3.750"
3-4 = 3.725"
4-5 = 4.185"
5-6 = 3.725"
6-7 = 3.750"
7-8 = 3.725"

Paul