Quench on a 340.

Posted By: woody30

Quench on a 340. - 04/21/12 02:48 AM

Maybe I'm not the sharpest pencil in the box but how do you get a .035-.040 quench out of a 340 with the piston .018 out of the bore?? Even with a .040 head gasket you're only at .022. That's not even considering milling the deck or heads. Are the heads on a 340 made special so this is possible?

Posted By: RapidRobert

Re: Quench on a 340. - 04/21/12 03:39 AM

You'd need a thicker composite gasket like the blue Felpro's. Not sure what the thickness of the FP blue SB ones are (might be .054")

Posted By: 471Magnum

Re: Quench on a 340. - 04/21/12 03:41 AM

[edit} my bad

Posted By: RobX4406

Re: Quench on a 340. - 04/21/12 03:58 AM

Quote:

Can't run a closed chambered head with the OEM high compression/domed piston. Need after market flat tops.

Edelbrock does make a version of the performer head for a stock type 340 piston. Not sure if it can be set-up for effective quench though.

That's just bad info for anyone that reads this. The stock OEM 340 piston is a flat top with valve reliefs.

I guess mine with closed chambers and flat top pistons out of the hole .022 is gonna blow up?

As mentioned, you just need a gasket the correct compressed thickness.

Those ede 340 open chamber heads are junk for building a quench engine. Makes things MUCH tougher. All the 340 sets I've had, the chamber gets cut off them so they become closed chamber! no guessing, reflector domes, none of that nonsense. Easier to build and measure with a flat surface

Posted By: ohiodemon

Re: Quench on a 340. - 04/21/12 02:40 PM

obtaining quench is going to require some sharp measuring and also possible head/block machining.
it's not done simply.

Posted By: Robbins

Re: Quench on a 340. - 04/21/12 03:08 PM

Quote:

Maybe I'm not the sharpest pencil in the box but how do you get a .035-.040 quench out of a 340 with the piston .018 out of the bore?? Even with a .040 head gasket you're only at .022. That's not even considering milling the deck or heads. Are the heads on a 340 made special so this is possible?

If the short block is together then like said run a thicker gasket.....if not then I machined my pistons tops to zero deck on mine.

Posted By: GO_Fish

Re: Quench on a 340. - 04/21/12 03:13 PM

stock 340 heads are open chamber and not designed for quench. They would need a lot of machining to create a quench pad, and then (as with a closed chamber aftermarket or magnum head) you would need the thick head gaskets as noted since stock 340 flat top pistons stick above deck.