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Discussion Starter · #1 ·
I have a 509 casting, 2 bolt main block bored to 4.155. I'm using a Scat 9000 Series crank, 6 inch scat rods with ARP cap screws, ARP main studs, Probe forged -14cc reverse dish pistons, with blueprint cylinder heads that have 195cc intake runners and 2.02 int. and 1.60 exhaust valves....The cam is a roller thumper cam that has .513 and .498 lift, 227 and 241 duration at .05...also using comp retro fit roller lifters, trick flow 1.5 roller rockers, and Comp chromoly pushrods, Comp dual valve springs, 670 street avenger with 68 primaries and 74 secondaries, .35 pump shooter...What do you think of my setup??
 

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I have a 509 casting, 2 bolt main block bored to 4.155. I'm using a Scat 9000 Series crank, 6 inch scat rods with ARP cap screws, ARP main studs, Probe forged -14cc reverse dish pistons, with blueprint cylinder heads that have 195cc intake runners and 2.02 int. and 1.60 exhaust valves....The cam is a roller thumper cam that has .513 and .498 lift, 227 and 241 duration at .05...also using comp retro fit roller lifters, trick flow 1.5 roller rockers, and Comp chromoly pushrods, Comp dual valve springs, 670 street avenger with 68 primaries and 74 secondaries, .35 pump shooter...What do you think of my setup??
Post the chamber size, piston deck height and gasket part number. I can't determine if it's a good build until I know the static and dynamic compression ratio. Also, if you will post the cam part number, it'll save me from looking it up. Thanks.:thumbup:
 

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I was looking for the 14cc reversed dome pistons on Probe's website. All I found was 15.0 reversed dome and 22.5 reversed domed for 400 ci engines. I hope you have the 22.5 reversed dome or your compression is going to be too high at 10.476 and a DCR of 9.068 with a .015 head gasket. With a .039 gasket your compression will be 9.924 and DCR will be 8.598. But then your Quench will be .064 which is best to be .040.
 

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Discussion Starter · #9 ·
I got the pistons from skip white and not the website and they are -14cc reverse dish...I dunno why the website doesn't show them...and I'm using 1 5/8 long tube headers with 3 inch pipe, true duals straight back...it's in a jeep yj
 

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They are probe fully forged srs pistons and they say -14 cc which should give me a 10.3 compression with 64cc heads I'm pretty sure
I'm with Mr. Minter, I don't see a 14cc dish piston for the 400 block from Probe. If you have such a piston on hand and intend to use them with 64cc chambers, the SCR will be on the order of 10.6:1.

With a 6" rod, the wrist pin will be pushed up into the oil ring, something that I will not build. You won't see a nickel's difference in performance between a 5.7" rod and a 6" rod and you don't have to crutch the ring land to prevent snagging.
 

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Discussion Starter · #12 ·
I don't have the part number but skips paper says -14cc and the piston looks like a two valve relief flat top with one half angling down...and I'm not worried about the oil ring
 

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Discussion Starter · #16 ·
With ~10.6:1 static compression ratio and that 12-600-8 camshaft, dynamic compression ratio will be 9.31:1. GOOD LUCK!
12-600-8 - Thumpr
Intake valve closes at 35.5 degrees ABDC @0.050" tappet lift.
So you are saying that .2 compression is enough to kill my engine? Since the cam calls for 9.5 to 1?? I doubt it but I'm interested to hear what you have to say:)
 

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So you are saying that .2 compression is enough to kill my engine? Since the cam calls for 9.5 to 1?? I doubt it but I'm interested to hear what you have to say:)
You're mistaken. Comp does not call for 9.5:1 minimum static compression ratio until you get to the 299THR7. Please get your stuff together before you try to correct me. See this page from Comp....
COMP Cams: Chevy 262-400 c.i. 8 Cyl '55-'98
Static compression ratio and intake valve closing point are tied hand in hand with each other. If you don't know your exact static compression ratio, then you have no business trying to choose a camshaft out of thin air. If you don't know how to match up a cam with a given motor, call the grinder for a recommendation.

With 10.6:1 static compression ratio and that short cam, the motor will rattle like a coffee can full of marbles from detonation and I doubt it'll live for 15 minutes before it breaks all the ring lands or holes a piston or 3.
 

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Discussion Starter · #18 ·
The kit I bought was said to have a static compression of 10.3:1 with 64cc combustion chambers but that's not the issue...I just want to know how you think it will run...using the six inch rod moves the piston higher in the bore for when my cam closes so I don't lose as much of a stroke
 

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Discussion Starter · #19 ·
And also mister this motor has been running pretty good for the last 3 years and I never hear any pinging...I just posted so I could see how accurate these forums are and if I would really wanna join...so that's why I posted this to see how many people would chime in about compression and say it wouldn't run 15 minutes or idle smooth...looks like my test is done:)
 
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