those old stock 307 were very porous motors. sometimes a overbore yields a scrap motor.
but i believe the answer is yes, i can be overbored to 4.00.

 

I have never heard anyone discuss rebuilding a 307 before. What are your plans for this engine? How will you build it up? What will you run it in?
See i have this theroy that a lot of 350`s in hot rods are really 305`s or 307`s(In descise). I think this holds true even more for the ,rigs that are not built by the owner.Like store bought!!!! Please let us know your plans for your engine. I am truely interested.
I don`t think i spell descise right??????
Thanks
Slider in Wa.

 

The current plans is to bore to 4.00, using the taller z28 pistons, and the eagle "h" beam rods. Is this a good combo or is my mech. just trying to unload some spare parts? THANKS DY

 

Im sorry, using the 400 "H" beam rods. He says this will be a high torque high rever! THANKS DY

 

The idea of boring a 307 .125" over has been around for along time. 30 years ago, the failure rate was about 1 in 10. Today you would have to take into account water jacket corrosion and such. A sonic check would be the only way to tell for sure. With 4" blocks so easy to get..... Don't know if I would go there or not.

Another thing to think on, the 302 pistons all had a tall dome. .350" was average. 11-1 with a 64cc head. Add another 1/4 to the stroke and compression will go higher. If the pistons are TRWs they will have a thick top and can be milled to drop the compression a bit. I think TRW is the only ones still making a 302 piston off shelf.

You can still use the 307 block if you have to. A 283 has the same pin height as the 302. A .030 or .060 over 283 piston will work with the 5.565" 400 rod and a 3.25" 307 crank. Will leave you about .035" in the hole. At .060 over you should get about 316 cubic inches. Almost the 327 you are talking now.

If you want more torque, a 305/350 crank can be added. Use the 307 piston and 400 rod. You can get a 339 inch high torque set up that a set of vortec heads will accent nicely. Dan

 

sounds like your builder is trying to get rid of all his oddball parts. use a 4.00 bore block and forget all the other stuff, use a 3.25 stroke 5.7 rod for a 327 or a 3.48 stroke 5.7 rod for a 350.

 

Originally posted by Dave Y.:
<strong>The current plans is to bore to 4.00, using the taller z28 pistons, and the eagle "h" beam rods. Is this a good combo or is my mech. just trying to unload some spare parts? THANKS DY</strong><hr></blockquote>


You need another mechanic.

<img src="graemlins/boxing.gif" border="0" alt="[boxing]" />

You are spending $$$ for a weird, odd ball setup that is not anything special.

Just go find a 350 and be happy

 

I would get a new mechanic. If you try to bore a 307 out to 4" you'll also need a plumber!