Straight 8 248 - 263 interchangeability...

[Guest Duanesk]

Will a 1951 263 engine(manual trans.) drop right into a 1946 Super? Will the front motor mount from the 248 bolt right onto the front of the 263 engine? Also, is the cylinder head and intake/exhaust manifolds interchangeable. Is the 1951 3 speed transmission exactly the same as the 1946?

Thanks for the help!!

Duane

1946 Super Conv.

[Guest imported_JPIndusi]

Sorry, cannot help on the motor mount and transmission interchange. However, the exhaust manifold and the valve body should be the same and will bolt up. The intake manifold will also bolt up but the 248 engine had a 3 bolt carburetor while the 263 intake manifold has provision for a 4 bolt carburetor.

Hopefully, The Old Guy will reply about the other issues.

Joe, BCA 33493

[palbuick]

Front motor mount will bolt up to new motor , The later motor had motor mounts on the side of block, and will be evident that motor is later model. Every thing else wil interchange.

Transmission may be a small problem, they are the same bolt pattern only difference will be the length of the tailshaft extension. Check wheel base of both cars, this will determine the length of the tailshaft. They are interchageable. Only intake that had 4 bolt carb was the upper series. should be an easy swap.

Jim Schlf

palbuick

[The Old Guy]

Joe and Jim covered most of your questions, but the 263 small series DID use a 4 bolt base carb. I have a 39 big series carb on my 263 because the 248 had 1 7/32 venturis, the 263 had a 4 bolt base with 1 9/32 venturis, and the 320 had 1 5/16 venturis. The 263 carb does not look like the 40 carb, and the 39 big series does. That is why I switched. It also lets it breathe a little better.

[Mrbuick714]

W ater pump?

[The Old Guy]

Ralph is right! You will need the later pump also. ( Ralph is always right, but he is even older than me, so that gives him more experience. )

[palbuick]

Hi Joe

Guess that makes three OLD GUYS around here. What one forgets there are at least 2 others to help or remember.

Jim Schilf

palbuick

[Guest Duanesk]

Thanks for the help "OLD GUYS"... I have a couple more questions. I read somewhere that you can use the later insert style bearing rods in the earlier engines. If this is true, can you use the 263 rods and pistons in a 248 engine (that's bored out)? Also, will the 41/42 factory dual carb intake have any interference problems with the exhaust and the motor mount boss on a 263 engine.

I originally wanted to keep the car all original, but haven't been able to locate a 1946 block (mine has a crack). The engine does run and drive fine and is probably repairable. I just want to weigh all my options.

Thanks again!!

The young guy!!

Duane

PS: I'm in my mid 30's and my friends think I'm the "old guy" with my old car!!

[The Old Guy]

The inserted rods have been used in the early engines, but I'm not sure of how they did it. The mounting boss on the engine will not cause a problem as long as you are using the front mount. The mount itself is what gets in the way. I have a 263 with dual exhaust in my 40 ,and it works just fine.

Boring the 248 to the larger (263) engine size is not recommended as you would have some thin walls . I think the max over bore they suggest is .040, and the 263 is .125 bigger

[Guest Duanesk]

Can a Dynaflow equipped 248 or 263 engine be bolted up to a manual transmission?

[Mrbuick714]

Crankshaft is different.

[blackduck]

can you tell me the stroke of a 263 engine please

[Pete O]

Bore and stroke of the 263 is 3 3/16 x 4 1/8

[Stripgear]

Just to confuse things more, I have a '40 block that you can have.

You'll have to talk to the "old guys" to see if it will fit.

Scott

[harbitz]

Is the 1937 248 block interchangeable with earlier or later 248 engines? I may need a new block for my 1937 - pending an oil analysis to determine if it has cracked again. It was once welded, but I suspect a new crack.

 

Can I use a block from other years. The rest of my engine is in excellent shape. The car has less than 50 miles on it since a major $15K overhaul in 2019. It is practically new inside. Thanks.