Thread: 305 vs 307 (whats the main difference?)

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Cooper here agian, thanks you evewryone for your input on the 307 questions i had earlier, but i have a couple more. Now that i knwo that a 307 is a 282 block, what does that makje a 305 besides 2 cubic inches smaller? And can you bore a 307 to a 327? And it was mentioned that you cna bore a 307 to a stock 350 so i assume you can make it a 355 as well? how would you go about doing that? thanks again for all of your help

cooper

Here's some help, cooper...

http://users.erols.com/srweiss/tablersn.htm

thats great thank you techinspector

There is a 307 stroker kit available where you bore the 307 .030 over add 3.563 stroke and 5.565 rods and get a 341. Should have good potential and be a little bit different.

Originally posted by Mr. Nova
Cooper here agian, thanks you evewryone for your input on the 307 questions i had earlier, but i have a couple more. Now that i knwo that a 307 is a 282 block, what does that makje a 305 besides 2 cubic inches smaller? And can you bore a 307 to a 327? And it was mentioned that you cna bore a 307 to a stock 350 so i assume you can make it a 355 as well? how would you go about doing that? thanks again for all of your help

cooper

A 307 is a 283 bore and a 327 stroke. Yes it can be made into a 327. Yes it can be made into a 350. NO, It CANNOT be made into a 355.

A 305 has a very small bore with a 350 stroke. No it CANNOT be made into a 350.

A 283 and a 307 can not be bored safely past 4 inch. That is a stock bore 327 or a stock bore 350

if a 307 can be made into a 327 or a 350, but cannot be bored safell past 4 inch how do you do it then?

crank. The 307 uses the 283 bore 3.875" and the 327 crank 3.250". Bore the block 0.125" to 4.000" and install a 350 crank 3.480". The block used to make the 307 is the late model large journal block, unlike the early 283 blocks which were small journal blocks and will not accept the 350 crank.

so you wud leave it at the standard bore and put a bigger crank in it?

A standard bore 307 with a 350 crank will produce 329 cubic inches.

awesome thanks

Nova, be aware though, that nobody does this because of the cost of custom pistons with a 3.875" bore and a modified pin location to accomodate the additional stroke.

In order to use off-the-shelf pistons, you'll need to bore the block to 4.000" to make a 350 out of it and then you risk heating because of the thin cylinder walls.

ok, well, the one im lookin at is a '71 nova 307, so it would be safer and cheaper to just go on and put the 350 crank in it in stead of boring it to 4 inches? so that would get me a 329 and i wouldnt have to bore the block at all?

You must have missed the first paragraph of my last post:

"Nova, be aware though, that nobody does this because of the cost of custom pistons with a 3.875" bore and a modified pin location to accomodate the additional stroke"

Using a 307 piston with the 350 crank will push the piston out of the bore by 0.115". Won't work with standard 307 pistons. You must spend big bucks to have Venolia, Ross or one of the other piston manufacturers make a custom piston with the pin location moved up 0.115" higher than the stock 307 pin location. It's not worth it for the modest gain. Drive the snot out of the 307 until it quits, then find a good small block 400 to rebuild and drop in.

yea thats weird, it didnt show that you said that before, but now it does, ok well thanks very much for your help this has been very useful to me!

Originally posted by Mr. Nova
ok, well, the one im lookin at is a '71 nova 307, so it would be safer and cheaper to just go on and put the 350 crank in it in stead of boring it to 4 inches? so that would get me a 329 and i wouldnt have to bore the block at all?

Nova , You just missed the point. As far as we know, If you want to stroke it,you have to bore it .125 and use a 350 crank with stock bore 350 pistons.
We do not know of any 329 pistons to go with a 350 crank,and what you have will not work.