I am buying parts to build my 350 and am not sure which pistons to buy for best relibility. Tight budget will not allow the more expensive JE or Ross. Goal is to be able to turn 6500rpm safely but will redline at 6000. Eagle 5,7 "Sir" rods will be used. Any info would be appreciated.

Robb71,

Either Speed Pro Forged or Silvolite are great pistons.

If you get the SP Forged, you might want to look into what the minimum piston to bore clearance is. I guess the new ones require less. The ones I bought for my 327 required .005" so I guess they were an old design! I haven't had any problems, but I wish the clearance was a little closer. Mine were lighter than the cast pistons though, so that's a bonus!

The KB is a hypereutectic as far as I know. The only downside is that you have to make sure you follow the instructions for the top ring.

Speed Pro makes a great hypereutectic piston also. They are teflon coated on the skirts - same as some OEM pistons. They are fairly inexpensive, and they hold up well. Best part is they don't require as much piston to bore clearance as a forged unit.

Mike

If you dont plan on spraying it..the Hypers are probably the best bet...The speed pro pistons are forged out of lead..not really just feel that heavy...I know your on a tight budget..but look at the wiseco pro-tru forged pistons..they come with rings and spirolocks and pins for around 400 bucks...depending on which size you need

The KB's are nice pistons and reasonably light, but like mentioned you have to run a much wider than normal top ring gap. I haven't tried the speed-pro hyper pistons but they run normal ring gaps. I am using the wiseco pro-true forged pistons in my 388. These pistons are very light and very high quality. Mine came with the pins, spirolocks, and hastings plasma-moly rings for about $420 thru www.dirttrackthunder.com (http://www.dirttrackthunder.com)

Another option is the Probe forged pistons. A SB flat top set is about $380 with moly rings and pins. Not sure about locks.

Also check out the new kid on the block, Mahle. They are a coated, ready to run piston, according to one article I perused on them.
[UMAHLE's surface treatments give pistons an extra level of protection. For example, GrafalŪ skirt coating decreases piston friction while at the same time improves the piston's ability to withstand scuffing, allowing reduced piston installation clearances with the potential NVH benefits. Hard anodizing the first ring groove significantly improves microwelding resistance. Multiple combinations of surface treatments can address virtually any automotive concern.{taken from their website} www.mahle.com (http://www.mahle.com)

RL=http://www.Mahle.com]www.Mahle.com[/URL]

Check out the Speed Pro TRW L2490-F30. Good forged flat top with two valve reliefs, relatively light weight at 497 grams, and $333 per set through Summit. Run 0.003" clearance if you know you'll never overheat or detonate. You can run 0.004" just to be safe with no adverse affects (noise or oil consumption). These pistons also utilize 1/16" rings, so you can run the latest gapless offering from Total Seal if desired.

I may as well get into the bidding war here! :D

The H618CP Speed Pro Hypereutectic can be had for $224 for a set of eight.

Mike

Thanks for all the replys! I found the Speed Pro forged L2256F in my Summit catalog for $223.60 At this point I don't think I can find a better deal. Just wish I had a weight compairson chart.

Those L2256F's are 605 g each. They are a rugged piston that will take a beating, but there are others out there for slightly more money and significantly less weight. The Wiseco's and Speed Pro forged mentioned above are all under 500 g each.

My Wisecos for 6" rods weigh 416 grams.

Originally posted by Robb71:
Thanks for all the replys! I found the Speed Pro forged L2256F in my Summit catalog for $223.60 At this point I don't think I can find a better deal. Just wish I had a weight compairson chart. Good deal graemlins/thumbsup.gif

i ran those exact pistons in my 355 daily driver and was real happy with them.i ran speed-pro moly rings and when i disassembled the motor after 20,000 miles the cylinder walls looked (and felt) like they were honed yesterday. graemlins/thumbsup.gif

L2256F are tanks.
Do not overestimate the difference of a lighter weight piston.Quicker,free reving,more instant throttle responce.=Lower ET's.
You would be better off getting a Hyper.

After doing some searching I found the Speed Pro "light weight" LW2256F 499gram at SDPC for $33.95($271.60 for 8) Not a bad price! Also for those looking CNC Motorsports has Eagle I-Beam rods for $189/Scat $175 and Eagle cast steel cranks sbc for $179/Scat $196. Summit has a Beat-A-Price Guarantee. Time to go shopping!!

cnc also has eagle H beam rods for 305.00...

Originally posted by ejrempel:
Also check out the new kid on the block, Mahle. They are a coated, ready to run piston, according to one article I perused on them.
[UMAHLE's surface treatments give pistons an extra level of protection. For example, GrafalŪ skirt coating decreases piston friction while at the same time improves the piston's ability to withstand scuffing, allowing reduced piston installation clearances with the potential NVH benefits. Hard anodizing the first ring groove significantly improves microwelding resistance. Multiple combinations of surface treatments can address virtually any automotive concern.{taken from their website} www.mahle.com (http://www.mahle.com)

RL=http://www.Mahle.com]www.Mahle.com[/URL] According to their site, Mahle pistons were found in stock on the LT-1, LT-5, and the 200HP 4.3 V6.

That's pretty impressive to me.

Engineguy Bill might correct me but ... I really dont think initial clearance is all that important. Once the piston is up to running temperature the clearance tightens up due to expansion. Different pistons expand more due to material and skirt design, but I bet they all end up at about the same running clearance. Without sounding too old .... how many of you guys remember the old 70 LT1's or the LS7's ... they used to sound like the pistons were swapping holes for the first few minutes until they warmed up. If you want to do an experiment, measure a piston across the skirts when cold, then run it under hot water for a few minutes and measure it again ... you will be surprised at how quick they change sizes.
As to the type of piston, the Sealed Power / TRW forged are pretty bullet proof. Most of them have a skirt coating now also ... nice piston for the price.