8 MPG?

[Vbb199]

PICS!!!!!

Mr above average

 

[Snoots]

Oh $h!t, here we go . . .

 

[Vbb199]

Oh $h!t, here we go . . .

Poke. Poke.

 

[Dysco]

Quench height... thank you! I couldn't remember the proper name. Squish zone... oh my Gawd pass the bong.
It is strange this gets looked over at the factory. Factory rebuilt engines are no better and that's twice the sin as it did had two chances to get done correctly.
IMO without a nice tight squished quench zone height (I just had too!) you have NOTHING and all the parts and cam you throw at will only gain a fraction of what's really available.
You want 20 mpg out of a 350...? Start here.

Squish zone, or more often Squish height is quite often the term used in the 2-stroke (motocross,etc) communities. So don't worry, you weren't off base.

 

[Red Rex]

It's more commonly known as "quench height". I always shoot for .040"-.045". Lingenfelter said .050" should be the max, and that .035" is getting close to the safe limit. Stock from the factory on a 60s-90s 350 could have been as high as .070" or more , depending on actual deck height and gasket thickness. Several years ago, I tore down a unmolested 1985 350 that had either a .038" or .041" gasket ( I forget which) with the pistons "down the hole" .030", for a quench of approx .070". Those GM engineers weren't dummies, so I have no idea why engines were built that way.

Just do I understand what you are saying, the distance from the top of the piston to the mating surface of the head when installed should be .040 to .045?

If correct what compression ratio would that produce withs 64 cc heads?

 

[Raybo135]

You do know it's actually the other way...? Imperial gallons, like Canadian average dick size, is larger than American..

I was referring to $$$$$!

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[Snoots]

Just do I understand what you are saying, the distance from the top of the piston to the mating surface of the head when installed should be .040 to .045?

If correct what compression ratio would that produce withs 64 cc heads?

You have to take into account the shape of the head of the piston.

 

[Red Rex]

I would be using flat top pistons

 

[Vbb199]

I would be using flat top pistons

i dont know your setup, but lets theoretically say you had a head gasket squashed down to .038, standard bore of 4 and stroke of 3.48 , with a 4.03 head gasket bore, and to split the difference of your deck to piston top of .040-.045 to .0425, and your flat tops, youd be somewhere around 9.5-10:1 comp ratio i would have to guess.....

i might be off

 

[shiftpro]

i dont know your setup, but lets theoretically say you had a head gasket squashed down to .038, standard bore of 4 and stroke of 3.48 , with a 4.03 head gasket bore, and to split the difference of your deck to piston top of .040-.045 to .0425, and your flat tops, youd be somewhere around 9.5-10:1 comp ratio i would have to guess.....

i might be off

You might be on

 

[shiftpro]

Squish zone, or more often Squish height is quite often the term used in the 2-stroke (motocross,etc) communities. So don't worry, you weren't off base.

I have squished a few two strokes... they liked it every time.
Take that as you may..

 

[Red Rex]

Appreciate you sharing your wisdom!

 

[roundhouse]

You'd **** if you knew what my dad's 07 dirtymax was getting with 850 ft ibs of torque...

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That’s a $6,800 option

Gotta do a lot lot lot of towing to save back that plus interest plus the pricy maintain And and repairs .

 

[idahovette]

That’s a $6,800 option

Gotta do a lot lot lot of towing to save back that plus interest plus the pricy maintain And and repairs .

And depreciation!

 

[Raybo135]

You do know it's actually the other way...? Imperial gallons, like Canadian average dick size, is larger than American..

Not since 1970 when Canada converted to the metric system. So, it's still about 70% of the American.

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