Built 250 6 cylinder motor

Can a 1965 gen-3 Chevy 250 motor take a 4.000 bore and work well for a vintage drag motor?

Block will be pour filled to within 1" of the deck. Water will be run in the block top and the head. Car will be towed to and from the line. 1/4 mile passes.

Currently the block is bored .040.

I will be taking .035 off the deck and running 327 forged pistons with a .125 solid dome milled to .040 to run 11.50 CR and 266 inches.

Why not find a 292?
Always crack check the inline six block for cracks inside along the oil galley.

Ricks Garage--- Mainly because I have the block already and H-beam rods are available for the 250 (5.7") in the aftermarket for a fair price.

Race rods for a 292 are custom ($600) and Custom pistons run ($550). The Forged 327 dome pistons (mill dome to .040) will make 11.5 CR and you can get set of 8 for $375.

Block has be hot tanked & magged for cracks and was good.

I'd ask Tom Langdon about your ideas. He would be "the" go to guy on 6 bangers.
http://www.langdonsstovebolt.com/

Just looking for someone that has 4" bored a 250 block and see if it worked OK?

I already know it can be done, just would like some real world running results.

Someone out in RRR land has got to have tried it

http://www.propowerengines.ca/

Tom, Contact these guys. I saw a reference on the Interweb that they build some 4" bore 250 sixes.

bobw -- I contacted propowerengines and they do build 6 cylinder engine for some dirt track classes up in B.C., Canada. Verify all cylinder thickness and even sleeve the #1 cylinder as it is prone to block cracks at the front behind the water pump. You can have a full water block or a block fill setup. Very high dollar and a bit out of my league.

Thanks for the site, they know their stuff when it comes to race motors.

Tom,
Just knowing it is done successfully is the key. That was your question. I'd say go for it considering you are filling the block.
Bob

OK guys, now that I know the block can be bored to 4.00" with it pour filled has anyone done a 4.00" bore on a Chevy L6 250 block with the water passages in the block still open.

I really would like to keep the cooling system for the whole motor if I can and pour filling an L6 motor is not as easy as a SBC V8. The cost of sleeving the motor is out of my bracket.

Jump in with comments as I would like to start on the machine work in the next few weeks.

Never done one but have a nice 250 w/4bbl and headers awaiting a project. Would love to see what you come up with.

Undercover Customs -- This motor will be for a vintage dragster I run currently with a full water jacket 194" motor. I am sure I will have to block fill the water jacket to keep the cylinder wall flex to a minimum. I would just like to hear from someone that has done a 4" bore on a 250" with the water jackets in place.

If this was going in anything but a race motor I would only Bore .060 over and run some SBC 307 FT pistons. With some head milling and a -0- deck you can have a 10.0-10.5 CR motor with full water jackets that will last a long time.