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-   -   396 Build Up (https://www.yenko.net/forum/showthread.php?t=109366)

VintageMusclecar 05-12-2010 04:24 AM

Re: 396 Build Up
 
Keith Black forged pistons w/17 c.c. dome

Keith Black forged pistons w/41 c.c. dome

69 Post Sedan 05-12-2010 04:35 AM

Re: 396 Build Up
 
Eric, those are the ones I have looked at but the pistons (743 grams) and pins (158 grams) are very heavy and I have been hearing that the sizes very a lot.

I'm not saying I won't run them but I would like to get a set that are lighter. I could have work done to lighten them up and purchase lighter pins but I would rather find a better set for around $600-$700. Maybe that's not possible...I don't know.

Thanks, Kurt

05-12-2010 06:00 AM

Re: 396 Build Up
 
For my two bits, if it was mine, I'd build the biggest engine I could and then call it a 396 [img]<<GRAEMLIN_URL>>/grin.gif[/img] A long (and I mean a <span style="text-decoration: underline">long</span>) time ago, the late Ralph Truppi told me there was considerable power gain in something like a 4.250-inch bore big block, going from 0.030-over to 0.060-inch over. The big reason I believe is to unshroud the valves. Not that long ago, another mentor, David Reher told me pretty much the same thing. Just food for thought.

Take care man...

Wayne

69 Post Sedan 05-12-2010 12:55 PM

Re: 396 Build Up
 
Wayne, it took me a while to decide whether to build a 427 or the CE motor that is in the car. I decided to run the 402 for multiple reasons but the most important one was when I found out from a previous owner that when he bought the car in 1975, this motor was in the car.

Kurt [img]<<GRAEMLIN_URL>>/beers.gif[/img]

05-12-2010 03:39 PM

Re: 396 Build Up
 
Hey Kurt...
Thats' cool. Can you keep me (us) in the loop with the project? I'd like to see more. Sounds like a <span style="text-decoration: underline">really</span> neat project!

Wayne [img]<<GRAEMLIN_URL>>/beers.gif[/img] (to you too!)

VintageMusclecar 05-12-2010 03:51 PM

Re: 396 Build Up
 
Kurt;

I just happened to have an original 402 L78 piston &amp; pin out in my shop. I just checked the weight on it with my digital scales: 833 grams for the piston and pin. (The 2287F's in your engine now are going to be even heavier than that, but I couldn't track down the exact weight on them)

The first KB piston (9948) checks in at 832 grams for piston &amp; pin.

The second (9949) checks in at 901 grams for both, but note that it's a .580&quot; solid dome piston. That big knot of aluminum on top does add weight, but you can have them lightened up for a nominal fee.

For comparison's sake, a JE 258207 piston (44 c.c. dome) comes in at 799 grams for piston and pin. As you've probably already found, unfortunately they're not listed as available for a 4.165&quot; bore, and they're ~$400 more expensive than the KB's anyways.

I just did some quick calculations on KB's website; the 9948's would give (approximately) 8.53-1 with a 119 c.c. chamber and 9.2-1 with a 110 c.c. chamber. The 9949's would give 10.6-1 @ 119 c.c and 11.7 @ 110 c.c.

At this point you need to find out what c.c's your heads are so you know how much dome you're going to need, then you can go from there.

Eric

p.s. re: sizes--I have a set of KB's here now that were dead nuts on the money for size. fwiw.

Chevy454 05-12-2010 06:29 PM

Re: 396 Build Up
 
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 69 Post Sedan</div><div class="ubbcode-body">I am still having a real problem with finding good pistons for my 402.

Does anyone have any recommendations on another piston company to contact for custom pistons? I realize it's not a standard piston but holy cow I don't want to buy their company...I just want 8 pistons made. </div></div>
Custom pistons and cheap will never be found together, *that* I can promise! LOL!!

CC your heads, and then you can get serious about a piston search...

69 Post Sedan 05-13-2010 12:47 AM

Re: 396 Build Up
 
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hotrodsled</div><div class="ubbcode-body">Hey Kurt...
Thats' cool. Can you keep me (us) in the loop with the project? I'd like to see more. Sounds like a <span style="text-decoration: underline">really</span> neat project!

Wayne [img]<<GRAEMLIN_URL>>/beers.gif[/img] (to you too!) </div></div>

Will do Wayne!

69 Post Sedan 05-13-2010 12:56 AM

Re: 396 Build Up
 
The 077 heads are being cc'd as we speak. From the factory are they are 118cc. They have been shaved but very little so I am thinking they are in the 117cc range but like I said, I should know within a few days.

I have a response from KB and they said that the 9949 pistons with a .040 gasket the compression is around 10.7 and with a .070 gasket it would be around 10.1.

Thanks, Kurt

Chevy454 05-13-2010 06:11 PM

Re: 396 Build Up
 
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 69 Post Sedan</div><div class="ubbcode-body">The 077 heads are being cc'd as we speak. From the factory are they are 118cc. They have been shaved but very little so I am thinking they are in the 117cc range but like I said, I should know within a few days.</div></div>
Don't be surprised if they're actually *bigger* than 118cc, even after a slight cut. The virgin 840s/291s I've done have all measured way big...stock spec was 108cc, but they'd come in anywhere from 110cc-112cc. Being as the 077s were over the counter race heads they might have a more accurate advertised size, though...[img]<<GRAEMLIN_URL>>/dunno.gif[/img]


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