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10:1 On today's pump gas? What's your CR?

989 views 7 replies 8 participants last post by  71RCKCRZR RYAN 
#1 ·
Soon to be ordering new pistons for my 5.0.
I used to build in the neighborhood of 10:1 compression.
With what I hear about today's pump fuel, I'm hesitant and wanted to check what some of you where running for compression ratio.
Yeah, I can mix but it becomes a pain.
Still think it's OK for 10:1?
 
#3 ·
Part of it depends on tire size, ring and pinion and elevation were you run.Aluminum heads and EFI it should be no problem.
 
#4 ·
I run a 351w @ 10.5 to 1 It pushs 450hp and is efi and runs great on super.
 
#5 ·
If i build my 408 its gonna run about 12:1 static compression but only about 8:1 dynamic compression so it shouldnt have any problems with pinging and such.
 
#7 ·
It is all in the machine work. We run 12.9-1 compression on a 529" Caddy and we can run it on 91octane. It will ping but it takes about 4000rpm's before we notice it. There is a couple things you can do and that is deck the block so that the pistons come out of the hole around .005-010". That is assuming that you are using a Felpro gasket that is .038" crushed. Doing this will get you the correct quech. So you have .038 - .010= .028" quech,or so one. We like to keep it around .025-.035" and really no more than that. Also a big help is to get the correct camshaft. You will have to spend a little more but it will be worth your money and time to get a cam from Elgin cams. www.elgincams.com. I believe that they are the best out there period. Talk to them and see what you think. Talk to John.
 
#8 ·
YOU CAN RUN WHATEVER CR YOU WANT BUT WHAT DETERMINS IF ITS USED IS THE CAM....YOU CAN BLEED OFF A LOT OF COMPRESSION WITH DIFFERENT CAM SPECS.A CAM MOVES YOUR POWER BAND UP OR DOWN IN THE RPMS. SO TALK TO DIFFERENT PEOPLE ABOUT WHAT WILL WORK WITH YOUR SETUP. 10 1 SHOULD BE FINE ON PUMP GAS.
 
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