263 Street Build

I doing up a 263 for a fellow. Just starting the tear down. The motor looked like a million bucks. We were to be disappointed.

There are no through bolts into the head, there should be no sealant or lock-tite used on the head bolts!

When lifting the head off, glass beads started to flow...

Take a look at the head!


If you are cleaning with glass, take some time and blow it out. I have a thermo cleaning system which uses steel shot for cleaning. It has a cycle which is supposed to allow the shot to work its way out, but you must always set the head or block on the shop floor and spend some time blowing it out and turning it over and blowing it out again!

A quick look at the valves look bad. Many of them are terribly "sunk", here is an bad intake on the right. It's a little late for me to as, but any comments on oversize valve choices. I have already got a set of sbc +0.200" I am figuring to cut down to size.

Here is a shot of the cylinder bore:
It looks like it may have got a light scuff, maybe with a ball hone, no ridge reaming... A quick check shows as much as .010" of wear in parts of the cylinder!
Tomorrow I will pull the bottom end apart.
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Back when I worked for a living we never used glass beads on an engine. There is always a corner that you cannot see or find and oil will stay there after all the cleaning and glass beads will be attracted there. It does not take many beads to wreck a rebuild. My old bosses said there is a place for glass beading but not on the inside of an engine. I always remembered their advise.
We chose another crank, had it ground 10/10 cleaned it up and balanced it. We chose to remove a couple of oil plugs. This allowed thorough cleaning of the oil holes. The plugs were then replaced with 1/8" pipe plugs. The plugs were set in blue loctite and peened.

The long crankshaft takes up a bit of room on the balancer!
Big Valves in a 263

I am probably going to post this and someone will come up with a much better valve choice, but here was my effort.

Doing a straight eight Buick 263 head, casting number 1340827.
Using Ford valves.

Intake: Sealed Power, V2171.
Head Diameter 1.682"
Stem Diameter 0.3429"
Length 5.07"
1980-82 Ford 255 4.2L V8

Exhaust: Engine Tech V1771N
Head Diameter 1.457"
Stem Diameter 0.3413:
Length 5.071"
1978-1986 Ford 302 5.0L OHV V8

Target spacing between valve is 0.060"-0.065"
to get to this I reduced the intakes to about 1.660" and the exhausts to 1.440" Then to restore comfortable margins by remove about 0.010" from the valve seat and about 0.010" to form a back cut.


OE exhaust stem height 2.245" above spring seat.
Intake stem height 2.285" above spring seat.
Exhaust spring installed height 1.980"
Intake spring installed height 2.000"

Head decked to 3.510" This will give a combustion chamber of about 84cc
original head 3.665" high
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Bob, how about reducing stem diameter of the valves to around a 1/4 inch. That would increase flow and less weight to move up and down. There should be some press in valve guides to make the conversion. These straight eights do not rev high enough to need more strength in the stems.
I agree, I don't know if I would be comfortable going lest than about 5/16" stems, but everything helps. Original valves are 3/8" stems. I looked long enough and these were readily available and economical with 11/32" stems. There may be better ones, but I didn't look long enough to find them. If you know some numbers post them for others:)

The intakes were 107 grams, 3 grams heavier than OE
The exhausts were 97 grams, 3 grams lighter than OE
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Balanced the pistons and measured the domes.

Rotating is 558gms.

Reciprocating is 171gms

Domes are 9.5cc

Piston with pin are at 525gms
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Anybody had the courage to do some major material removal on their heads or blocks?

This article suggest you can take .175" off the head!

This one says it can be done, but cautions it may be wise to be more conservative.

What did you do?


Active member

Bob, I suspect .175 is OK. An easy way to gain a small amount of compression. I did mine .020 and the block the same. Bored .125. Then sprung for aftermarket pistons for a compression increase to 9.5. A note of caution! The cylinders should be sonic tested to make certain the walls have enough meat for this much bore. I did not and payed the price. One cracked. Necessitated a complete teardown and sleeving the affected cyl.


In this case we are just using a common replacement piston at 0.030" oversize, so cylinder walls won't be a problem.

I am just setting up for piston valve clearances and have them to be about exh. at .275" and intake at .270" without a gasket.


With the Ford valves, and smoothed combustion chambers, the volume is about 97.5cc which, with a .015 head gasket yields about 7.02:1 cr, and with .045 gasket gives a 6.74 cr.
Removing about .050" yields about 7.25:1 compression ratio. .100" gives about 8.15:1 and .150" gives about 8.89:1.

After removing material, the measured combustion chamber was about 75.4ccs giving about 8.94cr.

After surfacing, without a gasket valve piston clearance is about 0.120".

Head bolts were shortened a bit and had the threads cut a little higher.
The push rods were also shortened. The ends are simply pulled off with a slide hammer then the rods shortened and carefully pushed back on. I would recommend experimenting to get a feel for the assembly.


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The cam is back, it is a symmetrical cam.
Grind Pattern B237X
Lobe Separation: 112
Advertised Duration: 284
.050": 213
Cam lift: .273"
Valve lift: .395"

After removing what probably turned out to be over 0.120" from the head, there is still 0.100" valve to piston clearance without a gasket. Slightly more, (0.105") on the exhaust. Attached you will find the best I could do with DynoSim5 for a stock and the modified build.

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The difference is at the flywheel flange. The dynaflow crank has a larger opening for the nose of the torque converter to fit into. The standard crank is machined, smaller, for the pilot bearing. I believe the flywheel bolt pattern is different, too.

How can you tell the difference between a automatic crank and a stick shift crank. I have a 263 as well
The one on the left is an auto with a flywheel locating center of about 3.600"
The one on the right is a standard with a flywheel locating center of about 3.75"
Mine is the automatic but it had a bushing in the center and had a flywheel and a clutch bolted to it. I tried to send a picture but it sail the file was too large. I’ll try when I get home on the computer. Is this possible??
When installing a "standard" thermostat that does not have a air bleed valve to stop air locking, drill a small hole in it. It may not have a check valve, but it will stop air locking.
This 263 was replacing a 248 in a '41.
It had two carbs and of course we wanted to keep them. We wanted to use the 263 motor mounts because it made for better balance and took a bunch of weight off the aluminum housed 5 speed. The good part is you can simply hang the motor and mounts on the engine, located it in the frame and bolt or weld them in place without spacers! But, when it came to mounting the dual carbs, there was an issue with clearance between the manifolds and the engine mount height. It had to be lowered.


I decided that if the engine mount sat about the center of the 4 bolt holes that there would be nice clearance and allow me to use the original 4 mounting holes. First step wack the engine mount side.


engine_mount_1.png engine_mount_2.png engine_mount_3.png

Here the mount is ready for tacking. There is no reason to turn the block part upside down, but I thought it might look better.


Here is the mount on the engine showing the clearance to the dual carburetor exhaust manifold.

engine_mount_8.png engine_mount_9.png

After test fitting the exhaust tube, I decided to cut the shoulder off the mount to reduce interferance. At this point, I would choose to lower the mount another 1/4", or as close to the lower bolts as I could feel comfortable, to allow for more pipe clearance.