Hey guys, I could of swore someone made a forged piston for a 400 block w/a 327 crank (3.25). Rod length will be either 5.7" or 6.0".

I know that most piston companies will custom make any piston, but I wondered if anyone knew of something in a catalog.

Thanks!!

If you use 5.85" rods you can use common pistons made for use with a 350 crank. 585 rods are common with the circle car crowd. Just watch your deck clearance.

Originally posted by dyno jonn:
If you use 5.85" rods you can use common pistons made for use with a 350 crank. 585 rods are common with the circle car crowd. Just watch your deck clearance. Sounds like a good idea John.

Looks like SCAT makes a H-Beam too:

2-350-5850-2100 5.850", 2.100" Pin, ARP 8740 Bolts

Oops, how do a figure out what compression using it that way?

I guess I just buy the lowest compression piston I can find.

Did I mention this is for a twin-turbo motor I am building?

most aftermarket piston companies will build you a set of pistons however you want.

Originally posted by dyno jonn:
If you use 5.85" rods you can use common pistons made for use with a 350 crank. 585 rods are common with the circle car crowd. Just watch your deck clearance. Just to confirm, I can use pistons intended for a 377 destroker w/5.7 rods and 3.75" stroke, but use them with 5.85" rods and my 3.25" stroke crank. Is this correct?

Speed-Pro#L2352f-.040 1.555 comp distance

Yes. At least with any of the SRP 377 pistons will get you to a 9.035" zero deck height. But you'll have to use a pretty thick head gasket to get the right quench. Something like at .05" gasket I guess?

(3.25/2) + 5.85 + 1.560 = 9.035

(stroke/2) + rod length + piston compression Ht= Zero Deck.

Have no idea how balancing will work out though.

Srp make a 1.260 Comp Distance piston,use a 6.125 rod and mill off .010

I moved this from your crank question:
Originally posted by bluerebl:
</font><blockquote>quote:</font><hr />Originally posted by Pat Kelley:
Be sure to get a 1.55 pin height piston which will give you 9.025 (1/2 stroke (1.625")+ rod (5.850") + pin height (1.550")). Many (most) aftermarket forged 350 pistons have this pin height. Using the 1.560 OEM pin height will push the piston above the deck. In other words, don't plan on decking the block unless you use thicker than usual gaskets. Posted on another topic:

Just to confirm, I can use pistons intended for a 377 destroker w/5.7 rods and 3.75" stroke, but use them with 5.85" rods and my 3.25" stroke crank. Is this correct? </font>[/QUOTE]The destroked piston has a 1.420" pin height. Adding this with the stroke and rod lenght gives us:

1.420 + 1.625 + 5.85 = 8.895. This is some .130" below the uncut deck. No way you can cut the deck that much.

You could use a 6.125" rod and a 1.250 pin height. This adds up to 9". Wisco has a -20cc 4.155" bore piston with 1.250 PH (#K208A3). This is basically a 3.50" stroke piston with a 6" rod. Since you are .25" shorter on stroke, you need an .125" longer rod hence the 6.125" rod.

Originally posted by Pat Kelley:
Wisco has a -20cc 4.155" bore piston with 1.250 PH (#K208A3). That's great Pat. There are two problems though, the that piston uses the oil rail support, which is a no-no for forced induction. But that doesn't matter because Wiseco disco'd that part number a long time ago.

Originally posted by Slowpoke70:
Yes. At least with any of the SRP 377 pistons will get you to a 9.035" zero deck height. But you'll have to use a pretty thick head gasket to get the right quench. Something like at .05" gasket I guess?

(3.25/2) + 5.85 + 1.560 = 9.035

(stroke/2) + rod length + piston compression Ht= Zero Deck.

Have no idea how balancing will work out though. If I ended up going that route, I'd still be good because Cometic makes a gasket 0.051" thick.

How 'bout this:

SRP has a 1.425 c/h piston w/-26cc dish in a 4.145" bore (0.020" overbore). Part number 206042.

Using a 6.0 rod and a Cometic 0.074" head gasket.

(3.25/2) + 6.00" + 1.425" = 9.05

Figure that my stock deck height is 9.025" and I'll have approx .010" decked for a straight deck.

So 9.015" deck, piston is 0.035 above deck, add a 0.074" head gasket= 0.039" quench. Did I do my math correctly?

Would that work or is that too much head gasket to get the 0.039" quench?

check this out.

http://www.speedomotive.com/400_to_350_w.htm

wait... .020 overbore. didn't think about that.

don't thay make off the shelf cranks in a 3.35in stroke or something along those lines? that may give you more piston choices that would work.

why not just call the piston manufactuers (if you haven't already) and ask if they make naything that will work for you off the shelf.

I thought on forced induction/nitrous application, you would like to possibly have the top ring slightly lower on the piston and the srp piston 206042 with 6 inch rod and the 0.074 gasket seems like a bad choice in my unprofessional opinion. Seems like having the piston out of the hole that much and the rings that much closer(to all the combustion heat) would be worse than the expense of having some custom pistons made. Maybe that piston with the little lt-1 sized rod of 5.94" would be a good compromise.

3.25/2 + 5.94" + 1.425= 8.99" zero deck height.

Caleb

Did Wisco really discontinue the K208A3? Its in the catalog I have from about 2 years ago. Caleb's idea looks pretty good, too. The 5.94" rod is available from Chevy. And he makes a good point about the top ring being so close to the top of the bore.

Thanks for all the help guys, but I think I am just going to build a 377 destroker afterall.

Mainly because of the piston issue, but even more because I can't find an aftermarket 3.25" stroke crank for less than $1000 and that's still not with the needed 400 mains.

So, now I am on the lookout for a 3.48" or 3.50" stroke forged crankshaft with 400 mains.

Here are the pistons I will very likely be using:

http://www.cnc-motorsports.com/product.asp?ProdID=8610&CtgID=8207

That's probably best. Going with an unusual B/S can create problems. Plus the extra cubes won't hurt.

Wow, this is probably the first time anyone has listened to one of my suggestions on this site. Kinda' makes me feel all warm and fuzzy inside :D

Just kidding (only about the warm & fuzzy part)

I'm glad I was able to make a useful suggestion. Keep us updated on the progress graemlins/thumbsup.gif

Geez, the Car Gods must like me today. I just found the crank I was looking for:

http://www.cnc-motorsports.com/product.asp?ProdID=11468&CtgID=7492