rick_rabies

gsr block
gsr head
ls crank and rods
wiscoe 81.5 pistons...

they seem to be bigger than ctr. my guess is over 12.1?
anyone know what CR the pistons are?

shiroitenshi

get clay and a measuring beaker in cc and measure the dome volume. not much of a point though since total cr depends on how much you milled your head and decked your block

98vtec

My xray vision and brain wave measuring tape say remove the piston, measure compression height and dome volume. Or look for a part number or stamp.

rick_rabies

^i would but...motor has been bored to 8.15 and fully assembled now...

shiroitenshi

lol, guess you just have to find out while tuning. if you have to retard the timing a lot to prevent knock, then your compression ratio and cams don't match. use bigger cams. if you don't, then use it without bothering with the technicalities. there is a reason you measure them before assembly, so an experienced engine builder can suggest a near suitable cam.

Madmood

I sure hope you have some adjustable cam gears for that thing.

shiroitenshi

adjustable cam gears are only for people who know how to use them madmood, if he didn't do clearancing on his engine, i think its a good thing it doesn't have adjustable cam gears.