706 to 241

How much do 241s need to be milled to maintain the same compression as the stock 706 heads?

you wont gain anything but a loss in wallet. the 5.3 heads flow same as the stock ls1 heads do

243's flow little more and have different springs and lighter valves

+1 on Quick's word's of wisdom (on the 241's) :lol:

And if your heads flow more cfm than is needed you will be losing and hp across the board. The idea is to keep the velocity of the air up. When you lose velocity you lose average hp and torque. So since your basically stock you can just get your heads short turn radius's changed a little (intake and exhaust) and will increase airflow and velocity for cheap. :thumb: some call it a ball job i believe??

... air can't see.. but its got a hell of a feel

not all 243s have lighter valves. Only the LS6 243s have lighter and longer valves. the 243s the come on the other motors have teh standard 2.0 valve that come in other heads

Oh im not looking for a HP increase. My 706 heads are cracked, just looking to replace them. Have a set of 241s with less then 20 miles I wanted to put on it.

i got a set of 706 heads i pulled off a motor not shure the milage but look good just need to be cleaned. ill sell them if u want them

thanks man I'll keep you in mind.

ya theres a general spec site that shows how much to shave down ill see if i can find it for ya

So you want to figure out how much to mill:

It takes about .005" milling of the block deck to remove 1cc of volume. It takes .007" milling to remove 1cc from an LS1 head

Simple Milling Math:

You have a stock 66cc chamber and you want to get down to 63cc

66-63 = 3. You have to remove 3cc's

.007 x 3 = .021. So to get your 66cc chambers down to 63cc you'd have to mill ~.021.

You can also do the reverse, say you want to mill a head .030 to figure out how many CC's that removes you take .030 / .007 = ~ 4.28. Milling a stock 5.7 head .030 puts your chamber at ~ 62.