Thread: 348 get or not

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There is a possibility that you are looking at a 409 instead of a 348. Print out the following info and take it with you to inspect the motor. Even if it turns out to be a 348, it's a score at the money you mentioned.
http://www.show-cars.com/numbers1.htm

You should also know that the Mark IV crankshafts (3.76", 4.00") have the same spacing as the 348/409 cranks. By cutting the main journal diameter from 2.750" to 2.500", the crank will theoretically drop into the block. All W and Mark IV motors use the same 2.200" rod journal size and same 6.135" rod length. So, a guy might be able to drop a 454 crank in (I have no idea of the grinding involved on the block to clear the crank) and make a W-427 (4.125" X 4.000"). Or use a 396/402/427 crank and make a W-402 (4.125" X 3.760").

Probably the biggest cost in doing this would be the pistons, which would probably have to be custom made unless another member of this board knows the whereabouts of some special pistons on a shelf somewhere.

Now, having said all this, I wouldn't spend a dime on making a monster W motor. You could build any garden variety 427 or 454 and drive around any W motor you could build. What I would consider doing is to build the motor back stock and enjoy a very unusual mill under the hood.
http://www.show-cars.com/enginekits.html

There are quite a few cams available for the W, here's a nice list..
http://www.show-cars.com/campage.html

W pistons....
http://www.bruneauperformance.ca/409...gineparts.html
I might talk to these guys about a very low compression piston (8.0:1) and mount a turbo with blow-through carb. A W-348 would think it was 500 inches with a turbo at moderate boost (6-8 psi).

Originally Posted by techinspector1

There is a possibility that you are looking at a 409 instead of a 348. Print out the following info and take it with you to inspect the motor. Even if it turns out to be a 348, it's a score at the money you mentioned.
http://www.show-cars.com/numbers1.htm

You should also know that the Mark IV crankshafts (3.76", 4.00") have the same spacing as the 348/409 cranks. By cutting the main journal diameter from 2.750" to 2.500", the crank will theoretically drop into the block. All W and Mark IV motors use the same 2.200" rod journal size and same 6.135" rod length. So, a guy might be able to drop a 454 crank in (I have no idea of the grinding involved on the block to clear the crank) and make a W-427 (4.125" X 4.000"). Or use a 396/402/427 crank and make a W-402 (4.125" X 3.760").

Probably the biggest cost in doing this would be the pistons, which would probably have to be custom made unless another member of this board knows the whereabouts of some special pistons on a shelf somewhere. .

the 454 crank will work and you can use the gm 3/8 454 thumb rods and the 454 crank nose needs to be cut down to use the 348/409 chain set or re work the timing cover for the bigger seal and the 454 damper? 454 chain set may work????? you will have to do some tin work and graft a 454 cover seal part to the w cover for the bigger seal the pistons any one can make but i think Ross sells them for the 409 shelf piston with the 4.000 but the 348 may be not you would have to call them