8 MPG?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Snoots

Full Access Member
Joined
Jan 23, 2013
Posts
8,893
Reaction score
18,770
Location
Georgia
First Name
Roger
Truck Year
1973
Truck Model
Jimmy Sierra
Engine Size
350 w/203
Oh $h!t, here we go . . .
 

Dysco

Full Access Member
Joined
Apr 12, 2019
Posts
393
Reaction score
174
Location
Wisconsin
First Name
Rick
Truck Year
1979
Truck Model
K10
Engine Size
400
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

Full Access Member
Joined
Jun 3, 2014
Posts
336
Reaction score
564
Location
Middle Ga
First Name
Andy
Truck Year
1984
Truck Model
K 1500 4 WD shortbed
Engine Size
350
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 :eek:, 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

Full Access Member
Joined
Jan 20, 2019
Posts
296
Reaction score
310
Location
Arvada, Colorado
First Name
Raymond
Truck Year
1976
Truck Model
K10 Silverado
Engine Size
400
You do know it's actually the other way...? Imperial gallons, like Canadian average dick size, is larger than American..
I was referring to $$$$$!

Sent from my SM-G960U using Tapatalk
 

Snoots

Full Access Member
Joined
Jan 23, 2013
Posts
8,893
Reaction score
18,770
Location
Georgia
First Name
Roger
Truck Year
1973
Truck Model
Jimmy Sierra
Engine Size
350 w/203
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

Full Access Member
Joined
Jun 3, 2014
Posts
336
Reaction score
564
Location
Middle Ga
First Name
Andy
Truck Year
1984
Truck Model
K 1500 4 WD shortbed
Engine Size
350
I would be using flat top pistons
 

Vbb199

B-rate Hillbilly Customs
Joined
Jan 12, 2018
Posts
9,116
Reaction score
15,479
Location
Salisbury NC
First Name
Vince
Truck Year
89, 79
Truck Model
89 Suburban R1500, 79 C10
Engine Size
350, 502
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

Full Access Member
Joined
Aug 31, 2012
Posts
4,855
Reaction score
6,095
Location
BC Canada
First Name
shiftpro
Truck Year
73-87
Truck Model
1500, 2500, 3500
Engine Size
350, 383, 454, 496!
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

Full Access Member
Joined
Aug 31, 2012
Posts
4,855
Reaction score
6,095
Location
BC Canada
First Name
shiftpro
Truck Year
73-87
Truck Model
1500, 2500, 3500
Engine Size
350, 383, 454, 496!
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

Full Access Member
Joined
Jun 3, 2014
Posts
336
Reaction score
564
Location
Middle Ga
First Name
Andy
Truck Year
1984
Truck Model
K 1500 4 WD shortbed
Engine Size
350
Appreciate you sharing your wisdom!
 

roundhouse

Full Access Member
Joined
Apr 5, 2014
Posts
669
Reaction score
528
Location
atlanta ga
First Name
justin
Truck Year
77,78,79,80 ?
Truck Model
K10
Engine Size
350
You'd **** if you knew what my dad's 07 dirtymax was getting with 850 ft ibs of torque...

Sent from my SM-G965U using Tapatalk
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 .
 

Raybo135

Full Access Member
Joined
Jan 20, 2019
Posts
296
Reaction score
310
Location
Arvada, Colorado
First Name
Raymond
Truck Year
1976
Truck Model
K10 Silverado
Engine Size
400
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.

Sent from my SM-G960U using Tapatalk
 

Latest posts

Forum statistics

Threads
44,424
Posts
957,546
Members
36,777
Latest member
paulteigrob
Top