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Largest Billet crank

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Aljav View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Aljav Quote  Post ReplyReply Direct Link To This Post Topic: Largest Billet crank
    Posted: Sep/19/2017 at 11:27pm
What is the largest stroke that can be used in an Indy Block. I believe I have heard of 4.250. Correct me if I am wrong.

Thanks,

Allan
69 AMX 9.86 132 mph 71 JAV/AMX and 69 Javelin, .. NAMDRA member #1106
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lenni AMC Quote  Post ReplyReply Direct Link To This Post Posted: Sep/20/2017 at 9:26am
Longest stroke is 4.250"

AMC Gremlin w/401
6.212 @ 117.01 - 1/8 Mile
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Aljav View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Aljav Quote  Post ReplyReply Direct Link To This Post Posted: Sep/20/2017 at 9:32am
I wonder if there is a reason why not longer. Pan rail interference, cam interference? Aluminum rods vs steel rods when it comes to clearances of the cam and rails?

Just wonder if anyone has checked this out.

Thanks Allan
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Boris Badanov View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Boris Badanov Quote  Post ReplyReply Direct Link To This Post Posted: Sep/21/2017 at 5:36pm


You run out of room, rod length becomes critical and the crank diameter will not support it.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote stickshifter Quote  Post ReplyReply Direct Link To This Post Posted: Sep/22/2017 at 6:36am
I run 4.150" with aluminum rods.  I do not believe 4.250 would be easy to do unless using steel rods.  Beyond that, the overall package is too small for anything longer.
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Aljav View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Aljav Quote  Post ReplyReply Direct Link To This Post Posted: Sep/22/2017 at 8:05am
Very Cool. Thanks for the response Kevin. That's the kinda info that I needed to know. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DaemonForce Quote  Post ReplyReply Direct Link To This Post Posted: Sep/22/2017 at 8:52am
Originally posted by stickshifter stickshifter wrote:

I run 4.150" with aluminum rods.  I do not believe 4.250 would be easy to do unless using steel rods.  Beyond that, the overall package is too small for anything longer.

This is likely the most engineering safe combination in a 401 crankcase. I would not dare go further than the 4.150" unless a taller deck option were there.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Boris Badanov Quote  Post ReplyReply Direct Link To This Post Posted: Sep/22/2017 at 11:42am
I do not believe that even with a taller deck you
can go much more. Even with steel rods Your outta room.

Taller deck would help the rod ratio and ring package crunch.
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Aljav View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Aljav Quote  Post ReplyReply Direct Link To This Post Posted: Sep/22/2017 at 12:07pm
When dealing with Chevrolet Big Blocks you often hear that the limitations are the rails and the cam location, Thus Aftermarket Big Blocks with raised cam locations and grinding or even wider rails. 

I know AMC Architecture falls between small and big block Dimensions, so the curiosity of limitations come into play. 

Helping my friend investigate possibilities before we persue this project.  

Like Wally Booth told me one time.. Build it bigger and Rev it higher!!Wink

Thanks.  Allan 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote garland performce Quote  Post ReplyReply Direct Link To This Post Posted: Sep/24/2017 at 7:49pm
My 4.00 stroke with steel rods has a lot of room
6.00 inch rods gave me a 1.240 comp height moved the ring pack down
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