I don't get some of u guys,Aported iron head will ping with 10.5 or so to 1.My 69 roadrunner I had up to 1979,and ran it on 93 octane and it had 10-1 from the factory, rebuilt it milled the heads 030. ran 40 degrees total with 906 heads with over 300 duration in a 383 Never made a ping,never ever. After running a 400 sbc alot of them run hot,because of not drilling steam holes.Am used to keeping engines at below 190,and I don't care what anyone says,My cars run faster at 160 than 200 don't care what the engineers say.Last 400 sbc ran so cool I never drilled the steam holes and had a toggle swith on my waterpump so I could build heat,at the strip because whatever temp I run the 1st pass,the rest of the day is run at the same temp. and if at least 5 builds in mags of 400's,383s,440s they mostly go for the XE285HL with iorn heads,without a problem. U no it alls think with 90 more cubic inches you can't go up on step,or going from the 241/247 @050 to 242/252 is WAY TOO Much. hey 360 rumble lookin foward to meeting u and talkin to ya the rest of u engine builders,if u can't say it nice keep it 2 ur self,I gotta hear about bold fonts,or I would tell u but I have to get paid,is that what u say to everyone askin a question...Pay me yeah....
