Re: I beam or H beam
[Re: DusterKid]
#2509939
06/18/18 12:31 PM
06/18/18 12:31 PM
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Joined: May 2005
Posts: 2,007 Apollo, PA.
B1MAXX
top fuel
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top fuel
Joined: May 2005
Posts: 2,007
Apollo, PA.
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Just my opinion: oem/aftermarket I beam.....ok for mild performance build. h-beam.....great high performance rod, would guess its in 90% of all 9-10 second bracket race style engines. Billet (steel/aluminum/titanium)I beam...best in my opinion for builds beyond that 9-10 second range. When I think of a race 11.5 to 1, 408 build, me thinks of a 4340 crank and h-beams. no science , all gut here.
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Re: I beam or H beam
[Re: DusterKid]
#2509979
06/18/18 01:36 PM
06/18/18 01:36 PM
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Joined: Aug 2003
Posts: 43,292 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,292
Bend,OR USA
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Are you wanting SB stock type rod and wrist pin end rods? If so either one will work I'm going to build a old time offset stroker 360 motor cast crank with SB Chevy 2.00 rod journal sizes and probably use a set of Speedway 6.125 long small journal Chevy I beam rods Lots of choices when starting a new build, take your time and check out every choice out there before deciding
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: I beam or H beam
[Re: DusterKid]
#2510175
06/18/18 10:01 PM
06/18/18 10:01 PM
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Joined: Oct 2007
Posts: 4,210 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,210
New York
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H is obviously stronger, which is why almost no OEM use them.
Boffin Emeritus
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Re: I beam or H beam
[Re: lewtot184]
#2510202
06/18/18 11:02 PM
06/18/18 11:02 PM
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Joined: Oct 2008
Posts: 1,176 East Coast
A/MP
super stock
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super stock
Joined: Oct 2008
Posts: 1,176
East Coast
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in my opinion, the lower the rod angle the more likely i'd choose an h-beam rod. I think the weak link will be the main caps. I always use Pro Gram main blocks and studs for any SB over 6700. There's a lot of walking going as the motor revs.
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Re: I beam or H beam
[Re: polyspheric]
#2510210
06/18/18 11:20 PM
06/18/18 11:20 PM
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Joined: Jan 2005
Posts: 3,635 Oakland, MI
dizuster
master
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master
Joined: Jan 2005
Posts: 3,635
Oakland, MI
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Either shaped rod will be fine. Pick one that's rated for your intended use (which comes down to cross section), and don't worry so much about the shape. I wouldn't be worried to use the Scat I-beams at all on your build. H is obviously stronger, which is why almost no OEM use them. Actually it's not strength related at all... it's the manufacturing cost/ease that pushes us (FCA) towards powder metal I-beams more then anything. Since the big/small ends are in the same direction as the I-shape, they can be easily formed, and VERY close to final shape which minimizes the machining costs. Even the hellcat rods are formed this way. https://www.youtube.com/watch?v=azGg68B-Glk
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Re: I beam or H beam
[Re: DusterKid]
#2510257
06/19/18 01:46 AM
06/19/18 01:46 AM
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Joined: Oct 2007
Posts: 4,210 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,210
New York
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Actually it's not strength related at all
NO, really? Should I have used the [sarc] tag?
Boffin Emeritus
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Re: I beam or H beam
[Re: DusterKid]
#2510258
06/19/18 01:47 AM
06/19/18 01:47 AM
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Joined: Oct 2007
Posts: 4,210 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,210
New York
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Widmer made some very interesting comments w/r/t beam shape 20 years ago specifically where in the power stroke gas pressure spikes, different between NA and turbo...
Boffin Emeritus
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Re: I beam or H beam
[Re: DusterKid]
#2510270
06/19/18 02:37 AM
06/19/18 02:37 AM
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Joined: Jan 2003
Posts: 31,074 Oregon
AndyF
I Win
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I Win
Joined: Jan 2003
Posts: 31,074
Oregon
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Dad wants to build a 360 stroked to 408. Will be an all out race motor, but on the milder side. 11.5:1, won't be spun past 6500 and will have around a 600 lift solid cam. At what point do you guys start using an H beam rod over I beam? At a certain rpm, higher compression? SCAT I beam rods will work just fine in your combination. I used the SCAT I beam rods in my 470/240 engine which makes 700 hp at 7000 rpm. I have over 100 dyno pulls on that engine and now it is going into the Duster for some drag racing. Here is a picture of the rotating assembly in that 470. I used a superlight SCAT crank, the I beam rods and some custom pistons.
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Re: I beam or H beam
[Re: DusterKid]
#2510480
06/19/18 07:12 PM
06/19/18 07:12 PM
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Joined: Jan 2003
Posts: 9,826 las vegas
70AARcuda
master
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master
Joined: Jan 2003
Posts: 9,826
las vegas
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Got a 360 stroked to 408 with scat 4340 I beams..nothing to grind...lighter weight...shifts at 6500..traps 6900.
Got a 2nd 408 ready to go in another car same set up..
Tony
70 AARCuda Vitamin C 71 Dart Swinger 360 10.318 @ 128.22(10-04-14 Bakersfield) 71 Demon 360 10.666 @122.41 (01-29-17 @ Las Vegas) 71 Duster 408 (10.29 @ 127.86 3/16/19 Las Vegas)
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