drewhen

iTrader: (5)

So, I dont post often but Im in the middle of my next build and looking to build 14:1 or better compression. Im probably gonna buy a schwanke shortblock. Im thinking his 427 w/ -8cc pistons. I want texas speed heads and cam just because I love their company and have had good success with them in the past. Here is my question with texas speeds 64cc l92 heads and a thin cometic gasket Im still only looking at 12.5:1, I want at least 14:1 because this motor will be ran off of E85. How much compression can I squeeze out of this combo and not have ptv clearance issues and not have to flycut the pistons. Gurus help.

Thanks, Andrew

Beaflag VonRathburg

iTrader: (176)

Get a custom domed piston made for your specific valve reliefs or have the chambers welded and put through a rehardening process.

Beau@SDPC

iTrader: (14)

we do have a manley HC piston on hand for the 416 LS3. that would be 4" stroke 4.068 bore. they are a 10cc dome with LS3 style valve reliefs. come with support rails and pins of course. rings are separate. $550 for the set.

drewhen

iTrader: (5)

So, whats the most compression I can get without having to purchase custom pistons? Say a -8cc piston and a 64cc ls6 head. That would be close to 12.5:1 would that setup have any ptv clearance issues with say a .610 lift cam

Schwanke Engines

iTrader: (1)

I think we would be able to get to 13.5:1 with a +3cc dome. Give me a call and we can discuss it.

KCFormula

iTrader: (4)

Domed pistons and milled heads. There is no secret. Why are you against running a custom piston?

pillagenburn

iTrader: (2)

I am extremely interested to see how this project ends up as well as what power and fuel economy ends up looking like.

ramairws6

iTrader: (33)

He's not against it...... just that is all they offer on their builds to try to make the shortblock sorta universal for either the L92 head or lS7 head. Also they can cut costs for budget builds to buy huge quantity's of pistons for a better price. Goold luck with your purchase on this motor...............

briannutter

We have a 9.76CC+ @ .295 Dome rise LS3/L92 dome that does it with a .245 intake and .170 exhaust depth. It fills the chamber nicely. The valve pockets are quite a bit deeper than you really need, but they could be shallowed to your engine builders spec. This nets 13.7:1 out of the box.

Often and engine builder doesn't really know the needed valve pocket depths ahead of time (due to valve drop and valve lift around tdc), so the easiest thing to do would be to check p to v and mill the head 2cc down to 68cc to hit your 14.0 number.

If you have a good idea of what the head can be milled down to prior, we can lower dome rise and volume (and maybe still shallow the pockets some) to get the lowest possible dome rise for the best combustion.

A lot of ways to hit your target. Let your engine builder know we can help.

Regards, Brian Nutter -Wiseco Automotive.