315 truck hemi compression ratio

Does anyone happen to know what the stock compression ratio is for the '57 dodge truck 315 hemis. All of the charts I've found say N/A for the truck motors but 9.25 for the earlier car versions. Thanks in advance!

 

MOTOR'S truck book says 7.6 CR 197 HP @4400 284 T @2400

 

You need to inform thehemi.com & other resourse sites of this, especially if it is a comprehensive list of truck hemi C/Rs!

 

Thank you for the info! Does anyone know why the compression is so much lower than the passenger version. Are the truck pistons special low comp, or do the heads have larger chambers?

 

different pistons

 

Which book is this? Can you provide more info?

Thanks!