Stroking
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From: North Yorkshire, England
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Racer
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From: loughborough Leics ENGLAND
I just keep looking at the bore where my piston and rod should be and think i never what to see that happen again LOL. So a bit of extra insurance and weight saving, more to ease internal balancing than high RPM potential. Like you say we all go OTT somewhere along the way..................
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From: Overland Park Kansas
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For one thing, you stepped up to a smaller, thinner ring set. It's comparable to the new stuff GM is putting in LS motors. Plus, it has a Napier ring for optimum oil control. By itself, this reduction in friction should outpace the 36 vs 25g difference you thought was a better option. (Plus, if you can find the ring-weight difference, I bet you've gained MORE than 36g.)
Did you read the FAQ info on the Pro vs Standard line of pistons?
SRP Professional is the latest addition to the SRP product line. These high performance piston kits include many advanced features while maintaining a price similar to the existing SRP Piston line when purchased with rings. New features include lightweight FSR forgings, accumulator grooves and high quality 2.250" long wrist pins. In addition, the SRP Professional line features an industry first 1.2mm, 1.5mm, 3.0mm ring package. The 1.2mm carbon steel nitrided top ring is extremely durable and offers reduced friction over 1.5mm and 1/16" top rings. A 1.5mm Napier (hooked face) 2nd ring is used to improve oil control over conventional taper-faced rings. The combination of these new features can reduce the piston assembly weight up to 81 grams when compared to traditional SRP Pistons. Weight savings can be even greater when compared to other forged piston brands.
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- 1986 Original Owner -
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From: North Yorkshire, England
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I think you made the right choice. I forgot to mention the ring package also has to differ in weight. I couldn't find the difference with a quick check today, but I am thinking the 25g difference in the pistons themselves doesn't tell the whole story.
For one thing, you stepped up to a smaller, thinner ring set. It's comparable to the new stuff GM is putting in LS motors. Plus, it has a Napier ring for optimum oil control. By itself, this reduction in friction should outpace the 36 vs 25g difference you thought was a better option. (Plus, if you can find the ring-weight difference, I bet you've gained MORE than 36g.)
Did you read the FAQ info on the Pro vs Standard line of pistons?
SRP Professional is the latest addition to the SRP product line. These high performance piston kits include many advanced features while maintaining a price similar to the existing SRP Piston line when purchased with rings. New features include lightweight FSR forgings, accumulator grooves and high quality 2.250" long wrist pins. In addition, the SRP Professional line features an industry first 1.2mm, 1.5mm, 3.0mm ring package. The 1.2mm carbon steel nitrided top ring is extremely durable and offers reduced friction over 1.5mm and 1/16" top rings. A 1.5mm Napier (hooked face) 2nd ring is used to improve oil control over conventional taper-faced rings. The combination of these new features can reduce the piston assembly weight up to 81 grams when compared to traditional SRP Pistons. Weight savings can be even greater when compared to other forged piston brands.
For one thing, you stepped up to a smaller, thinner ring set. It's comparable to the new stuff GM is putting in LS motors. Plus, it has a Napier ring for optimum oil control. By itself, this reduction in friction should outpace the 36 vs 25g difference you thought was a better option. (Plus, if you can find the ring-weight difference, I bet you've gained MORE than 36g.)
Did you read the FAQ info on the Pro vs Standard line of pistons?
SRP Professional is the latest addition to the SRP product line. These high performance piston kits include many advanced features while maintaining a price similar to the existing SRP Piston line when purchased with rings. New features include lightweight FSR forgings, accumulator grooves and high quality 2.250" long wrist pins. In addition, the SRP Professional line features an industry first 1.2mm, 1.5mm, 3.0mm ring package. The 1.2mm carbon steel nitrided top ring is extremely durable and offers reduced friction over 1.5mm and 1/16" top rings. A 1.5mm Napier (hooked face) 2nd ring is used to improve oil control over conventional taper-faced rings. The combination of these new features can reduce the piston assembly weight up to 81 grams when compared to traditional SRP Pistons. Weight savings can be even greater when compared to other forged piston brands.
Got another question, that I'm sure sounds kind of dumb, but don't want to get stuck with the wrong part. The crank I ordered, is Scat 4-350-3750-5700-L. Is listed as 3.750" stroke and 5.7" rods. They don't list a one piece rear main crank for 6" rods, but they have the two piece rear main crank for 5.7" rods (4-350-3750-5700) and 6" rods (4-350-3750-6000). Am I stuffed because I have the one piece rear main or will the extra .300" be compensated by the raised pin position of the piston?
Last edited by Ray Quayle; May 31, 2016 at 02:46 AM.
Melting Slicks
Joined: Mar 2008
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From: Santa Maria, CA
I did read that Gregg, one of the reasons I decided to go with them. Thanks again for you help.
Got another question, that I'm sure sounds kind of dump, but don't want to get stuck with the wrong part. The crank I ordered, is Scat 4-350-3750-5700-L. Is listed as 3.750" stroke and 5.7" rods. They don't list a one piece rear main crank for 6" rods, but they have the two piece rear main crank for 5.7" rods (4-350-3750-5700) and 6" rods (4-350-3750-6000). Am I stuffed because I have the one piece rear main or will the extra .300" be compensated by the raised pin position of the piston?
Got another question, that I'm sure sounds kind of dump, but don't want to get stuck with the wrong part. The crank I ordered, is Scat 4-350-3750-5700-L. Is listed as 3.750" stroke and 5.7" rods. They don't list a one piece rear main crank for 6" rods, but they have the two piece rear main crank for 5.7" rods (4-350-3750-5700) and 6" rods (4-350-3750-6000). Am I stuffed because I have the one piece rear main or will the extra .300" be compensated by the raised pin position of the piston?
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Joined: Nov 2003
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From: Overland Park Kansas
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The crank I ordered, is Scat 4-350-3750-5700-L. Is listed as 3.750" stroke and 5.7" rods. They don't list a one piece rear main crank for 6" rods, but they have the two piece rear main crank for 5.7" rods (4-350-3750-5700) and 6" rods (4-350-3750-6000). Am I stuffed because I have the one piece rear main or will the extra .300" be compensated by the raised pin position of the piston?
After going thru all this, I finally discovered the 6" option for forged later on. I'm thinking it may be the 435050L also works with 6" rods. I almost decided to resell my cast stuff but, again, my builder talked me out of it.
Anyway, call to make sure on that. I'm betting that 5700 crank does work with 6" rods.
(The raised piston pin position does compensate for the longer rod.)
Last edited by GREGGPENN; Jan 19, 2011 at 07:59 PM.
Melting Slicks
Joined: Mar 2008
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From: Santa Maria, CA
I'd call Scat on that. Seems to me I was under the same impression (that Scat didn't make a 1-pc RMS 383 forged crank for 6" rods). I also wanted a 6" forged setup but thought I couldn't get it in SCAT with a 1-pc RMS. So, I started considering the 5.7" option more seriously. Then, I found a 5.7" set of Wiseco pistons for a killer price. Then, my builder convinced me I didn't need forged when I found a $150 builder's Scat 935050L.
After going thru all this, I finally discovered the 6" option for forged later on. I'm thinking it may be the 435050L also works with 6" rods. I almost decided to resell my cast stuff but, again, my builder talked me out of it.
Anyway, call to make sure on that. I'm betting that 5700 crank does work with 6" rods.
(The raised piston pin position does compensate for the longer rod.)
After going thru all this, I finally discovered the 6" option for forged later on. I'm thinking it may be the 435050L also works with 6" rods. I almost decided to resell my cast stuff but, again, my builder talked me out of it.
Anyway, call to make sure on that. I'm betting that 5700 crank does work with 6" rods.
(The raised piston pin position does compensate for the longer rod.)
Le Mans Master
Joined: Feb 2005
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From: The Motor City
Ray,
I like the way you think. I've felt it's better to do what you're going to do now to the lower end and have no regrets. Later down the road if wanting to change cams, heads, intakes, and or do power adders is easy, and can then be a real possibility if the rest can support the mods.
Good luck on your project,
Mick
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From: Overland Park Kansas
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Yeah, I'd done that too. I didn't find out about the option until I called last summer. Again, it seems like the 5.7 crank is compatible with 6" rods. I can't remember the details though.
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LOL...
Ray,
I like the way you think. I've felt it's better to do what you're going to do now to the lower end and have no regrets. Later down the road if wanting to change cams, heads, intakes, and or do power adders is easy, and can then be a real possibility if the rest can support the mods.
Good luck on your project,
Mick
Ray,
I like the way you think. I've felt it's better to do what you're going to do now to the lower end and have no regrets. Later down the road if wanting to change cams, heads, intakes, and or do power adders is easy, and can then be a real possibility if the rest can support the mods.
Good luck on your project,
Mick
Thread Starter
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From: North Yorkshire, England
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I think you're right Gregg. I haven't heard back from Scat yet, but it seems that the difference is in the counterweights and that the rod length listed for each crank is the minimum rod length recommended for that crank for ease of balancing. I'll let y'all know what Scat actually says, but since all the forged one piece 383 complete rotating assemblies use the 4-350-3480-5700L crank regardless of 5.7" or 6" rod length, I think I'm OK. Stay tuned.
Racer
Joined: Apr 2002
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From: loughborough Leics ENGLAND
Ray i think our on the right lines. If you used a 5.7 rod with the 6.0 rod spec crank the piston skirts will contact the counterweights. This is the issue. Using the 6.0 rod with the 5.7 spec crank is not an issue as far as i am aware. Balancing should be ok with the lighter pistons you have picked.
Thread Starter
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Ray i think our on the right lines. If you used a 5.7 rod with the 6.0 rod spec crank the piston skirts will contact the counterweights. This is the issue. Using the 6.0 rod with the 5.7 spec crank is not an issue as far as i am aware. Balancing should be ok with the lighter pistons you have picked.
Shoot me an email so we can get these bolts shipped.
