Jump to content

1967 340 4bbl rebuild no cheap pistons


Guest
 Share

Recommended Posts

has anyone ever heard of boring a 340 out to be a 350 and using the 10.25 to 1 compression 350 pistons in the bored out 340 block?<BR>It seems most numbers fit the picture. can anyone help me?<P>The 2bbl 340 has available pistons(9:1), but the 4 bbl 340 requires a piston that does not exist anymore.<P>If you have any info that might help me I am at dan.jubenville@sympatico.ca<BR> cool.gifcool.gifsmile.gif

Link to comment
Share on other sites

I'd look hard at available fuels before completely dismissing the 9:1s. The 10.25s are going to require high octane fuel or additives to be happy and not ping holes in themselves. The 9.0s will run happily on 93 octane.<P>This is one modification I have no problem doing. It will allow the car to be used and enjoyed and gassed up almost anywhere.

Link to comment
Share on other sites

You don't want the 10.25:1 pistons in a street-driven 340.<P>I have to run a 2:1 mix using 110 octane leaded racing fuel to get mine to stop pinging.<P>And, that's after 20 years of trying everything else. <P>When I rebuild, it will be with 9:1 pistons.

Link to comment
Share on other sites

We bored out a 225 and put later pistons in it and strange as it may seem,the engine wound up with 231 cubes .It ran fine .I have a near-new 340 short-block I would sell.

Link to comment
Share on other sites

I have a 340 bored .050" with 10.5:1 forged 350 std. pistons and late model 350 rods with ARP bolts. Be careful the mach shop understands .050 not .060!

Link to comment
Share on other sites

Thanks for your input. I have decided to slide the old pistons(with standard rings) back in until they smash their way out of the side, then I will likely rebuld the 2 bbl block .050 to get a 350 out of it 10.25:1. I have found I can get away with 94 octane fuel as long as I keep her to the boards. After a year of my torchure and 2 intake lobes worn round, all my pistons and valves looked ok (ie not burnt)<P>sorry if i seem a bit unprofessional, it's because I am unprofessional.<P>once again thanks guys, I didn't think anyone ever thought about poor old buicks like my betsy anymore, but it sounds like you all have some interest....

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...