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- Thread starter Money pit
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Island Girl
Well-Known Member
Welcome from the warm sunny Caribbean,
You'll find a wealth of helpful knowledge and experience here.
Tell us a bit more about your new T . . . if you do it a few words at a time in ten posts, you'll be able to post some pics of it.
You'll find a wealth of helpful knowledge and experience here.
Tell us a bit more about your new T . . . if you do it a few words at a time in ten posts, you'll be able to post some pics of it.
Money pit
New Member
Thanks happy to be here . Sbc with 462 cast double hump heads as far as I can tell , 11to 1 compression, , steel crank . Haven’t got any further into it then that yet . Been working on other gremlins on it like brakes and tires and rear end . Trying to figure out what the previous guy did and didn’t do .
Island Girl
Well-Known Member
2old can be a bit of a curmudgeon at times, but he knows his shit.
11 to 1 with cast iron heads is going to need race gas to keep from destroying itself from detonation.
Even with aluminum heads, which cool much better, that's still too high.
Figure 9 to maybe 9.5 or so is the upper range for cast iron heads while 10 to 10.5 is max with aluminum.
If it really is 11:1, it means someone built it that way with multiple mods done, as it wasn't a stock option.. . . . Hopefully they did everything right and do a low budget build.
Whenever you get something like that, it's always a good idea to check it out carefully, a small camera that works with a smart phone and fits thru a plug hole can be your friend, along with a compression tester.
If it's really high comp. you won't see stock looking pistons and will show higher cylinder pressures.
If it was running fine when you got it, and not rattling with pump gas, chances are that it's not really anywhere near 11:1 . . . . best check it out though to be sure and to actually know whet you do have.
By steel crank, do you mean forged as opposed to cast, or an aftermarket 4340 alloy crank?
11 to 1 with cast iron heads is going to need race gas to keep from destroying itself from detonation.
Even with aluminum heads, which cool much better, that's still too high.
Figure 9 to maybe 9.5 or so is the upper range for cast iron heads while 10 to 10.5 is max with aluminum.
If it really is 11:1, it means someone built it that way with multiple mods done, as it wasn't a stock option.. . . . Hopefully they did everything right and do a low budget build.
Whenever you get something like that, it's always a good idea to check it out carefully, a small camera that works with a smart phone and fits thru a plug hole can be your friend, along with a compression tester.
If it's really high comp. you won't see stock looking pistons and will show higher cylinder pressures.
If it was running fine when you got it, and not rattling with pump gas, chances are that it's not really anywhere near 11:1 . . . . best check it out though to be sure and to actually know whet you do have.
By steel crank, do you mean forged as opposed to cast, or an aftermarket 4340 alloy crank?
Money pit
New Member
Running on race fuel , was running on it when I got it . Yes forged crank not cast , not one rattle in it had a holly carb with a old intake didn’t seem to run right so I put a new intake and a 650 edelbrock on it . When I’m able to get pictures up I have some when I had top half open . It also came with what looks to be a 671 blower was part of the stuff it came with .
And that's the important part. I'd have to dig out my cam card to answer you, but just off the top of my head I know that the lobe separation is only 108 degrees so that is going to help make it more low octane friendly. What all this says is that blanket statements about this or that static compression ratio and engine knock or ping can be very misleading.
Indycars
Well-Known Member
I built a SCR/DCR and cranking pressure calculator that you can download here on
this forum. Just be sure to page down to post #7, it has the latest version.
Don't let all the different numbers scare you, there are several that don't make a big
difference and can just be left at their default. But technically they are a part of the
calculation and I'm all about accuracy. Such as the volume above the first ring up to
the piston top.
Dynamic & Static Compression Ratio Calculator
this forum. Just be sure to page down to post #7, it has the latest version.
Don't let all the different numbers scare you, there are several that don't make a big
difference and can just be left at their default. But technically they are a part of the
calculation and I'm all about accuracy. Such as the volume above the first ring up to
the piston top.
Dynamic & Static Compression Ratio Calculator
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