Ported 516’s with OVERsized intake valves

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8:1 is gettin real high for iron heads.
I was going to get same pistons but with a 20cc dish from 440source (and rebalance if needed) until you guys opened my eyes with these chambers. Now hoping to squeak by with the flat tops and if I have to, a thicker head gasket
 
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I was going to get same pistons but with a 20cc dish from 440source (and rebalance if needed) until you guys opened my eyes with these chambers. Now hoping to squeak by with the flat tops and if I have to, a thicker head gasket

You might can tune it......you'll have quench in your favor. I just tuned some light spark knock out of my fresh slant 6 build. It came in at 10:1 static and 7.9 dynamic, but no quench and with the piston in the hole .175" at TDC. That's a good habitat for detonation. But I did several things including limiting total to 30 and putting initial at 20 and no more spark knock. I feel sure with the added quench you'll have, you'll be able to deal with it.
 
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Maybe they were shot peened after to give a cast affect?
 
I have a set of 915s with 2.18/1.74 valves that are kissing close. The only reason I put the 2.18 intakes in was it was the third refresh so a few 2.14s sat to low for another grind. My 915s are 68cc and started 75cc +- they have the same chambers as the 916s.
 
I have a set of 915s with 2.18/1.74 valves that are kissing close. The only reason I put the 2.18 intakes in was it was the third refresh so a few 2.14s sat to low for another grind. My 915s are 68cc and started 75cc +- they have the same chambers as the 916s.

Those as well as the 516s can be some really nice heads.
 
I have a set of 915s with 2.18/1.74 valves that are kissing close.

Close? To each other?

Stock BB heads have the valve guide spacing at a nominal 2.070”.
The stock 2.08/1.74 valves should be about .160” apart.
The intake valve going up to 2.18 reduces that number to .110”(.050” a side bigger), which is still a mile of room.

An Indy 440-1, which has the same valve guide spacing as stock, and set up with 2.25/1.81 valves has the valves about .040” apart.
(2.070 - 1.125 - .905 = .040)
That works out to the same as if you had 2.18 intakes and 1.88 exhausts.
(2.070 - 1.090 - .940 = .040)

I’ve had Ede RPM and MP replacement MW heads here that were set up with 2.19/1.88 valves.
 
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Having a chamber cc‘d Monday morning to get an idea of where I’m at. I will post it.
Hoping for 90 or better
 
Well so much for the flat tops. It will be just over 10-1 with 20cc dish piston from 440Source. Dynamic 7.95-1

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7.95 is tuneable. I've done it and without quench. Do you have a picture of that dished piston?

Same photo for all the dished pistons they sell. I called them today, this piston is 15grams lighter than the flat tops.

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I believe they are Icon pistons. The pistons I bought from them last year were.
 
Yes they are icon, but only 440source offers this icon piston with a 20cc dish. The listed icon is 12cc dish... 440source has at least 1 other piston with more CC’s than what’s Icon has listed. Seems they take out an extra 8cc for 440source. I forgot to ask when I called
 
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We built a 440 with 516 heads and 2.14 intake and 1.81 exhaust valves, with flat tops, its not quite 11-1, customer adds just a splash of 110 octane, it runs good in a Duster 11.00's in the 1/4
 
We built a 440 with 516 heads and 2.14 intake and 1.81 exhaust valves, with flat tops, its not quite 11-1, customer adds just a splash of 110 octane, it runs good in a Duster 11.00's in the 1/4
What camshaft is in it ?
This is a 489
11.5 with flat tops
10-1 with 20cc dish
 
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I'd go higher 12/1 or 13/1 and run e-85.

You know I might just go this way. I think I’m going to leave the flat tops, try mixing fuel and if that gets old I’ll try an E-85 carb.
There are stations all around me that sell it.
 
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