Tried google and the search function and couldn't find an answer. Good light pistons for 350s. I know the Speed Pro forged ones are an old heavy design...what other options are there.
thanks

 

CP Pistons, Bill Trovato helped design them

 

http://www.btrperformance.com/products.html


pistons & other treasures in the link

 

https://m.summitracing.com/parts/dms-6020x-4100
Anybody heard anything about these pistons?
The only CP carillo pistons I could find were in goofy diameters like 4.065

 

I'm working with DSS to do the same in multiple sizes. I'll know for sure once I meet with them at the PRI.

 

i was told years ago you can have the speed pros lightened. the cost was about 150. Dont know how true that is but thats what i was told a long time ago.

 

Mark, I thought you were a big fan of Racetec/Autotec stuff, are they not making as good of stuff, is it just price difference.
Also was curious if there was a down side to the smaller ring packages for combo, track & street.

 

I'm still a fan of the Racetec stuff but DSS may be willing to do a shelf stock piston in various sizes. It would still sport the better ring pack but be available much quicker than a true custom piston. Same material as well, could be a win-win.

 

Since the 1970s I have been using 350 Chev pistons with floating pins, and bush the rods down to .927". If you use race pistons, it saves about 1/2 pound per assembly, but you do have to deck the block .055" more because their compression height is that much lower than Olds. Now I am using Mahle stuff.

 

Based on some awesome feedback here on ClassicOldsmobile.com I stepped up a little and decided on Forged Aluminum 4032 Small Block Chevy 400 Pistons Wiseco Pro Tru 4.125 OD (0.068" overbore) compression height 1.425" with 1/16, 1/16, 3/16 rings, and 6.200" long 5140 Eagle I beam rods for Small block Chevy (have to grind the rod journals down to 2.100" vs 2.125 stock) The 1.425" CH and 6.2" rod raises the piston 0.010" which helps increase my compression without milling a lot off the heads and affecting valve train geometry.


This set up in theory is positive in a lot of ways:
piston weight
pin weight
floating pin
thin modern ring design (reduced friction, improved compression sealing)
I beam rod vs stock forged rod, (improved strength, reliability)
Forged piston vs stock cast, (improved strength, reliability)
Increased displacement 362ci, vs 350ci (more boom boom)
improved rod/stroke ratio (internet says this is good?)
improved bore/stroke ratio (Revs faster?)
CH and rod length combo raises piston 0.010" (less milling of block or heads)
minimal 5cc valve relief dish (keeps compression high)


This was not a huge cost increase as the SBC parts are low price/high volume.


Ryan

 

But a few inaccuracies here. And did you check the clearance on the wrist pin vs the piston boss? Sometimes you have to grind a little off one side of the small end of the rod because Chevy rods are offset, Olds are centered.

 

Thanks Mark,

Your help has been keeping me moving ahead step by step!!

I am a rookie and don't understand the pin concern, but need to know so I can verify with the engine shop.

Please continue to chime in more.

Hope this isn't thread stealing?

Ryan

PS: The rings I selected are the minimum thickness allowed in PSMCDR rules, no metric rings:-) otherwise I would have. 0.070" overbite max as well.

 

Overbite is over bore:-)

Also measuring and going for a real 9.9 to 1 static compression.

Ryan

 

I have a set of TRWs that have been substantially lightened at my shop. They were the ones in the Mashers motor that had .014" piston to wall clearance. Needless to say the skirts collapsed.