k31th less WHY; more WOT Site Developer 28,291 Member For: 16y 8d Gender: Male Location: Melbourne Posted 10/12/19 12:15 PM Share Posted 10/12/19 12:15 PM yeah, of course 103 isn't 103.9, but who knows what their marketing is saying as they don't list the bore size... with 103mm stroke length, the bore size would need to be around 93mm to have 4.2L displacement. with 103.9mm stroke length, the bore size would need to be around 92.6mm to have 4.2L displacement. with the stock bore size of 92.26mm, the stroke length would need to be around 104.7mm to have 4.2L of displacement Link to comment Share on other sites More sharing options...
arronm Dropping a turd Gold Donating Members 9,520 Member For: 16y 5m 22d Gender: Male Location: Perth Posted 10/12/19 12:18 PM Share Posted 10/12/19 12:18 PM (edited) exactly. My first calc was wrong. So why bother with 103mm 2mm oversize piston. Dont think so.. Edited 10/12/19 12:22 PM by arronm Link to comment Share on other sites More sharing options...
k31th less WHY; more WOT Site Developer 28,291 Member For: 16y 8d Gender: Male Location: Melbourne Posted 10/12/19 12:22 PM Share Posted 10/12/19 12:22 PM as far as I'm concerned raising the stroke on a Barra motor is pointless whichever way they want to market it Link to comment Share on other sites More sharing options...
arronm Dropping a turd Gold Donating Members 9,520 Member For: 16y 5m 22d Gender: Male Location: Perth Posted 10/12/19 12:40 PM Share Posted 10/12/19 12:40 PM These are nice though. https://www.spoolimports.com/spool-products/spool-crankshafts/ford?engine=294 Link to comment Share on other sites More sharing options...
k31th less WHY; more WOT Site Developer 28,291 Member For: 16y 8d Gender: Male Location: Melbourne Posted 10/12/19 12:50 PM Share Posted 10/12/19 12:50 PM the stock displacement ones or the 3.7L displacement ones? Link to comment Share on other sites More sharing options...
arronm Dropping a turd Gold Donating Members 9,520 Member For: 16y 5m 22d Gender: Male Location: Perth Posted 10/12/19 01:33 PM Share Posted 10/12/19 01:33 PM All. Nothing like forged Link to comment Share on other sites More sharing options...
k31th less WHY; more WOT Site Developer 28,291 Member For: 16y 8d Gender: Male Location: Melbourne Posted 10/12/19 01:36 PM Share Posted 10/12/19 01:36 PM interestingly there's no 4.2L cranks there... let's see if they show up due to the popularity requirements of the stroker kit... my guess is it won't end up there. Link to comment Share on other sites More sharing options...
arronm Dropping a turd Gold Donating Members 9,520 Member For: 16y 5m 22d Gender: Male Location: Perth Posted 10/12/19 02:14 PM Share Posted 10/12/19 02:14 PM Power is in rpm. De-stroke and spin to 8k 1 Link to comment Share on other sites More sharing options...
k31th less WHY; more WOT Site Developer 28,291 Member For: 16y 8d Gender: Male Location: Melbourne Posted 10/12/19 02:18 PM Share Posted 10/12/19 02:18 PM that's right. stroke is pointless if it moves the bore/stroke ratio further away from 1:1. the more stable it is and the least amount of transmissive forces allow it to run up to higher rpm which allows it to then make the power you're referencing #winning. Link to comment Share on other sites More sharing options...
k31th less WHY; more WOT Site Developer 28,291 Member For: 16y 8d Gender: Male Location: Melbourne Posted 12/12/19 12:53 AM Share Posted 12/12/19 12:53 AM morning all, happy Thursday Link to comment Share on other sites More sharing options...
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