Stroker crank questions
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 2,337
Likes: 14
From: Norfolk VA
Stroker crank questions
I'm looking for a stroker crank for my 383 build this spring. I have narrowed it down to two brands Eagle or Scat. My question is do these cranks have the 3.75 stroke and 350 main journels? Are they internally balanced? If not does anyone make internally balanaced stroker cranks?
Drifting
Joined: Apr 2002
Posts: 1,716
Likes: 4
From: New Baden Illinois
They both have the 3.75 crank and the 350 journals. You can get both of them with the external balance in the cast crank. You can get the Eagle cast in an internal balance.
If you get the forged versions, they are internal balance.
If you get the forged versions, they are internal balance.
Melting Slicks
Joined: Jul 2005
Posts: 2,060
Likes: 46
From: winter haven florida
St. Jude Donor '12
you can get an eagle forged internal balanced 3.875" stroke kit for a 350 with forged .030 srp pistons for about $1600. this will give you a 395 ci small block. that is what i am going with on my current build.
Race Director
Joined: Apr 2000
Posts: 17,676
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
There is a nodular iron ( cast ) Scat 9000 internal balanced 3.75 stroke with 350 mains now, that would be my choice. Make sure it is measured correctly before install 
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
Most stroker cranks are internally balanced these days. If given choice, forget about external balancing. Also, more good news. The newer stroker cranks require less if any block clearancing. Cast is fine for the street up to 6500 RPM and even more. But in a stroker, I'd definetely machine for four bolt mains and use studs. Fairly cheap insurance.
Good luck!
Good luck!
Racer
Joined: Jan 2006
Posts: 395
Likes: 0
From: Orange massachusettes
Not to high jack thread, but has anyone actually spoken to a crank manufacturer and found out at what rpm they recommend upgrading from cast crank to forged unit?? Lots of different opinions on how much rpm a cast crank can take. Just my opinion, when you start spinning ANY engine ABOVE 6000 rpm frequently, your better off w/forged crank and forged pistons. I'm Very interested in what the MANUFACTURER of cranks (and pistons too for that matter) has to say. Doesnt seem to be worth risking a $4000-$6000 engine, to save $800 on a cast rotating assembly vs cost of forged rotating assembly. Then again, if your not gonna spin it past 6000 rpm, I quess its money in the bank.
Race Director
Joined: May 2005
Posts: 10,674
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From: Millington Illinois
St. Jude Donor '08-'09
Not to high jack thread, but has anyone actually spoken to a crank manufacturer and found out at what rpm they recommend upgrading from cast crank to forged unit?? Lots of different opinions on how much rpm a cast crank can take. Just my opinion, when you start spinning ANY engine ABOVE 6000 rpm frequently, your better off w/forged crank and forged pistons. I'm Very interested in what the MANUFACTURER of cranks (and pistons too for that matter) has to say. Doesnt seem to be worth risking a $4000-$6000 engine, to save $800 on a cast rotating assembly vs cost of forged rotating assembly. Then again, if your not gonna spin it past 6000 rpm, I quess its money in the bank.
If you go to the time and effort of building a motor that will see high RPM and upgraded HP why use a cast crank and hyper pistons? Even the low powered L82 had forged pistons, forged rods, forged crank and 4 bolt mains. These were lucky to put out 260 flywheel HP and had a 6000 RPM redline.
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Tech Contributor
Joined: Aug 1999
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From: At my Bar drinking and wrenching in Lafayette Colorado
I've been seeing a heckuva lot of Scat and Eagle cranks breaking. You do know these are made in China, right? They come out of the box bent, out of balance, and out of tolerance on the journals. We don't use them except as a last resort.
The bone-stock GM 400 crank is a much more reliable crank - and better quality - than the cheap aftermarket ones. There are some good expensive aftermarket cranks that are good, but for a reliable budget build-up, find a standard-sized 400 crank rather than the cheap aftermarkets. A properly prepped stock 400 crank will rev reliably through 6500, and will easily take 500 horse. External or internal balance is no big deal.
But I've only been doing this for 30 years, so I probably don't know what I'm talking about.
The bone-stock GM 400 crank is a much more reliable crank - and better quality - than the cheap aftermarket ones. There are some good expensive aftermarket cranks that are good, but for a reliable budget build-up, find a standard-sized 400 crank rather than the cheap aftermarkets. A properly prepped stock 400 crank will rev reliably through 6500, and will easily take 500 horse. External or internal balance is no big deal.
But I've only been doing this for 30 years, so I probably don't know what I'm talking about.
Safety Car
Joined: Jun 2002
Posts: 4,135
Likes: 1
I've been seeing a heckuva lot of Scat and Eagle cranks breaking. You do know these are made in China, right? They come out of the box bent, out of balance, and out of tolerance on the journals. We don't use them except as a last resort.
The bone-stock GM 400 crank is a much more reliable crank - and better quality - than the cheap aftermarket ones. There are some good expensive aftermarket cranks that are good, but for a reliable budget build-up, find a standard-sized 400 crank rather than the cheap aftermarkets. A properly prepped stock 400 crank will rev reliably through 6500, and will easily take 500 horse. External or internal balance is no big deal.
But I've only been doing this for 30 years, so I probably don't know what I'm talking about.
The bone-stock GM 400 crank is a much more reliable crank - and better quality - than the cheap aftermarket ones. There are some good expensive aftermarket cranks that are good, but for a reliable budget build-up, find a standard-sized 400 crank rather than the cheap aftermarkets. A properly prepped stock 400 crank will rev reliably through 6500, and will easily take 500 horse. External or internal balance is no big deal.
But I've only been doing this for 30 years, so I probably don't know what I'm talking about.
------------------------------
Safety Car
Joined: Jun 2002
Posts: 4,135
Likes: 1
you the man lars.. cant wait to see you in action again if we ever have another chicago tour,,,,if you ever come around,,ill take you on a tour of a b c channel 7 on state and lake,,meet the news anchor girls,,,go thru that whole building with ya buddy,(w l s radio on 9th floor,,,espn on 7 seen mike ditka there,,,oldies 1000 the old wcfl station)im now the building electrican,,, case you dont know i re did the 383,,, got 500 miles now,,,she was built by a ex nascar guy who did dale earnhearts sr's builds,,,my 383 was his last build and he retired,,, he dynoed it and she is 431 hp and 532 tq,,,,, now it is really a necc to have depends undergarments on while in use!!!! seriously bill and i would love to see the man in action again ,, this time instead of a msd 6 a box,,, im chrome plating the biggest sledge hammer i can find the ultimate ''hammer of the gods"" remember when you tweaked it,,,i took it out,,everyone laughed because i almost sh#t my pants? its a hella of a lot better,you gotta try her out!! later carl------------------------------------------------------------------
Last edited by carl a; Mar 17, 2007 at 06:58 PM.
Race Director
Joined: Aug 1999
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From: WI
Race Director
Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
Instructor
Joined: Jun 2006
Posts: 105
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From: central Texas
Cheap can still be strong...
My kid's shop teacher (hell he was also my shop teacher in college too) had some of his students build a 383. Used a GM 400 crank some used magnafluxed and cleaned rods a set of low buck hyper pistons a Lunati cam and an old Weiand Team G intake. Then he taught them how to port match the heads and intake with a grinder and how to put it all together and break it in so it would last. I bought it for what he had in it in parts... Total $1600... and even though it hasn't been dynoed, it makes soooooooo much more power than the stock 350 that it is scary... You don't need to spend big to build relaible power... as for the Chinese cranks, he said the same thing... you kinda have to watch. The GM 400 is a way better option for the $$$$$$$
Safety Car
Joined: Jun 2002
Posts: 4,135
Likes: 1
thats what my first 383 had,a 400 crank, now i put in a new eagle,weighed out machining the 400 /the same cost new crank,,would of have had to go with oversize bearings on the 400,,,still have it in case, new sounded better than ovessize bearings on the 400
