Thread: 10.4:1 cr on everyday driver?

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i have a 327 with double hump heads, .30 .30 cam and flat top pistons. im just wondering if the 10.4:1 cr is goin to be to much for an everyday car.

my dads car has a 355 with 11:1's and he drives it everyday from spring to snow. before my nova had this motor it had another much tamer 301 with 11:1's drove it the same <was before he bought his car that he has now> you should be fine..........scooter

You'll probably have to dial back the timing from optimum, especially in the heat of the summer. As ambient temp drops you could probably push it up some.

I know of a guy who runs 10.5:1 compression in a daily driven 468 powered El Camino. California runs two different formulations of gas, winter and summer. The winter is better and he will actually run the car on 89 octane during the winter. During the summer, he has to run 91. It is only possible using a knock sensor and computer which can dial out timing if detonation begins. He runs some really high initial timing, too. Something along the order of 26 degrees. He has been averaging 25+mpg. 310whp and well over 600lbs of torque. He said he uses really long rods (427 tall deck) and a cam with a tight lobe speration to keep cylinder pressures down enough at idle to hold off detonation. Also, very tight piston to cylinder head clearences are mandatory.

In conclusion, were gonna need to know more about the engine to tell you what is safe. You should be safe, but don't be cheap and try to put anything less than premium in there.

hey guys thanx a bunch. iv been wondering if i have a set of forged or cast pistons is there anyway to tell i cant find any cast #s or anything. oh and i thought i read someplace that 327s did not come as a 4 bolt main but mine is, is this odd by any chance. thanx alot guys and i hope to learn more from all of ya.

Remember, a common practice is to make a 2 bolt 4 bolt by some machining. Chances are that you have Cast pistons if they are factory, unless this is a Race motor(SS) or Vette motor. Maybe some Early 327s had forged, but im not 100% sure.

thanx for the info, is there any way to tell if they are forged pistons from cast just by looking at them? and also what would you suggest is a safe redline on a 327 hydrolic lifters stock springs i believe?

does the sbc bolt up to fiero trans-auto or manual?

got a rear engine going here myself

Heres a question I ask you, "do you know the difference between static and dynamic compression ratios.