Most Compression to put on stock 318

[xroadrunnerx]

What would be the most compression a 318 engine could handle for a daily driver and not fail? What heads would be best for this? Keeping in mind, will not be doing any bottom end work, so, stock pistons, rods and crank. Current compression is 8.5:1
Thanks.

[Jims451]

There is too many variables here. First you would need to define daily driver
I have a friend that has a 14:1 compression daily driver (has aluminum heads, really bif cam, etc.)

Using stock pistons you will have a hard time getting compression to the 9.2:1 the earlier (pre 1970) 318's had.
I would look for the 1967 318 Closed chamber heads and have them milled, this should help.
Because the stock pistons sit down below deck, you can have the crank rod throws turned down and offset to get a slight stroke increase which will increase compression and engine displacement.
I think I paid $90 to have a crank offset ground, where a standard crank grind was $60, so for an extra $30+ you get a decent benifit of more compression and displacement. I said $30+ because the thicker 0.030" under rod bearing set was about $8 more than the more common 0.010" under bearing set.

[rumblefish360]

As a side note, pump gas is good to about 9.5 unless the cam gets large. I run a 10-1 engine with the purple 292 cam without problems. A smaller cam will create more presure than a larger one that bleeds it of at low rpms.