Light 350 pistons
#1
Light 350 pistons
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
thanks
#3
#4
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
Anybody heard anything about these pistons?
The only CP carillo pistons I could find were in goofy diameters like 4.065
#7
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.
Also was curious if there was a down side to the smaller ring packages for combo, track & street.
#8
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.
#9
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.
#10
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
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
#11
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) Newer designs are even thinner.
I beam rod vs stock forged rod, (improved strength, reliability) True
Forged piston vs stock cast, (improved strength, reliability) True
Increased displacement 362ci, vs 350ci (more boom boom)
improved rod/stroke ratio (internet says this is good?) Up to a point
improved bore/stroke ratio (Revs faster?) That's not really the deciding factor on rev speeds.
CH and rod length combo raises piston 0.010" (less milling of block or heads) Depends on the dish or valve reliefs in the piston used, not an automatic
minimal 5cc valve relief dish (keeps compression high) See above
This was not a huge cost increase as the SBC parts are low price/high volume. True
Ryan
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) Newer designs are even thinner.
I beam rod vs stock forged rod, (improved strength, reliability) True
Forged piston vs stock cast, (improved strength, reliability) True
Increased displacement 362ci, vs 350ci (more boom boom)
improved rod/stroke ratio (internet says this is good?) Up to a point
improved bore/stroke ratio (Revs faster?) That's not really the deciding factor on rev speeds.
CH and rod length combo raises piston 0.010" (less milling of block or heads) Depends on the dish or valve reliefs in the piston used, not an automatic
minimal 5cc valve relief dish (keeps compression high) See above
This was not a huge cost increase as the SBC parts are low price/high volume. True
Ryan
#12
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.
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.
#14
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.
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