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Looking for a 3.75" stroke crank for a 383/396 N/A stroker (if your recommended crank is different between the two then I'll take two recommendations)
Only requirement is that it needs to be a one piece rear main seal. I do not want to run adapters and I do not want to convert to a two piece. I would prefer not to spend $3,000 on a crank or else I would go with the Callies Magnum. If that is the solution then so be it but I am hard pressed to believe that that is the only solution. Callies does not carry a 1 piece in any of their Compstar lineup. I am thinking forged crank, cast seems dumb for this engine. Buy once cry once.
Don't ever go cast for a stroker. Either Eagle or Scat is fine. There have been some QC issues with Eagle in the past, however. My advice is no matter what crank you get, make sure to measure it to ensure all tolerances are good. That goes for journals, snout, flywheel/flexplate flange and pilot bearing hole.
I have a Scat crank in a 472 Pontiac Big Block. Just wanted to confirm my prejudices
I’ll poke around for a Scat crank. I have heard the same things about Eagle. I hear awesome things about Callies as well but no one piece RMS? That is just silly lol
So this is a rods question but it does directly relate to the crank so I will leave it here. 6" or 5.7" rods? From what I hear it is better to have 6" rods to reduce skirt and cylinder wear but 5.7" has better cam clearance. Reason I ask is because Scat only offers cranks with 5.7" rods in a one piece rear main seal.
That question has been rehashed to death over the years with no clear winner. I have Compstar 6" H-beam rods in my 396 and can still fit a normal sized cam core. I think one of the arguments which stands out the most is that a 5.7 means a piston with thicker ring lands? Not 100% on that?
Is it oil leaks that makes you say no to 2pc seal? If so there is a 1pc conversion seal that works good. Has a slit at the top you rtv, but that’s it.
im running one on my 415.
Yes I hate oil leaks. I also figure there is a reason that we modernized to a one piece seal. Another reason (and this is just me being overly OCD) is that the car came with a 1 piece rear main which means I want to keep my 1 piece rear main.
I am not a big fan of conversions for stuff like this, just one more added part I guess, but I am keeping it in mind for sure.
Here is another rods related to crank question. So the reason that Scat crank only allows for 5.7" rods is because that is how it is balanced. I figure I am re-balancing/checking for balance anyway so does it really matter if I go with 5.7"/6" rods?
I had not selected my rod manufacturer but I was most likely going to go with Scat. I may end up saving a lot of time and effort and just buying the full Scat rotating assy with Mahle pistons. (If the compression ratio ends up to what I want it with the piston they offer)
those are a minimum length (to clear pendulum) and not the only length to be used. Longer is fine, balance may change a hair, but that’s dependent on rotating weight of rod and piston weight.
I would never trust a factory balance. Once a rotating assy is chosen, INCLUDING flywheel or flexplate, it should all be balanced together. Always go for an internal balance and neutral balanced flywheel or flexplate.
I have the Scat forged 1 piece RMS using Scat 6" rods, SRP pistons. It's in a Golen 383 shortblock. Chad replaced my initial 383 when the Eagle cast crank became a 2-piece crank. He replaced the block also. Have had it about 15 years now with over 45k mi on it.
Have the rotating assembly neutral (aka internal) balanced. Then just use a stock neutral balance damper...or I chose the ATI. Get a neutral balanced flexplate BUT absolutely have it checked that it is in fact zero balanced.
I had no cam clearance issues with my Comp XFI. You will need to clearance the block for rod bolts in a few places. Locations will identify themselves on mockup rotating motor by hand. I did use my stock windage tray by using 1/8" washers on the 3 main cap long studs and one on the oil pump bolt to stand it away from the crank. I also use stock pan. Audition it without gasket and rotate engine by hand with ear to the pan. You will likely need to clearance near #2 rod. There was just a slight scratch on inside of pan when I did (rod bolt) it which would have likely cleared with the thickness of the FelPro pan gasket, but I gave a little more clearance by using the big end of a wood baseball bat pushing on inside of pan that I put on folded towel. Worked perfect.
those are a minimum length (to clear pendulum) and not the only length to be used. Longer is fine, balance may change a hair, but that’s dependent on rotating weight of rod and piston weight.
That makes pretty good sense but I have a question then: What is the point of offering a crank that has a minimum length of 6" over a minimum length of 5.7"? What is the benefit of a larger pendulum?
@SS RRR Oh for sure. It will be balanced again no matter what.
@****** Thanks for the tips! I will be going with the ATI most likely.
Awesome then I will probably go with that Scat crank I posted up earlier. Anyone up for a 5.7" vs 6" rod thread?
All about piston speed. Longer rod reduces it when dealing with longer strokes. Nobody builds our cars to putt around in. We like higher RPMs, as do the engines we build for them. Small base circle cams help accommodate a longer rod. Feet per minute vs RPM you want to make power and be comfortable in determines appropriate rod length.
(not my quote):
"While average piston speed is not affected by rod length, there is a difference in piston speed at varying points through the stroke. Shorter rods are faster through mid-stroke and spend less time at top dead center, while longer rods are slower through these areas but spend less time at the bottom of the stroke."
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Crank recommendations? 
