CLASS RACER FORUM - View Single Post - Has anyone ever had an issue with using a 2 bolt main

FED 387 · 10-15-2012, 10:54 AM

I think part of the reason 4 bolts were used in some applications was for durability/engine life like in trucks or marine engines. RPM ranges also come into play here too. Stock/Sprint car/endurance racing where you are off and on the throttle constantly tends to want to stretch the cranks. Using a 2 bolt crank in a low RPM NHRA Stock class car equipped with a Small Block Chevy engine where the engines are not running extremely high RPM (like over 9500-10,500 or maybe more) in most cases would probably be sufficient.
Yes for the added insurance that a 4 bolt offers it's probably worth the extra $$$, but to just go out and build a 4 bolt from the get go for a 6800-7000+ RPM short burst engine might not justify the extra cost but you can always convert the block from 2 to 4 (if the rules allow it) if you feel you need a to. my 2 cents worth FED387

10-15-2012, 10:54 AM	#1
FED 387 VIP Member Join Date: Jun 2006 Posts: 3,420 Likes: 529 Liked 333 Times in 180 Posts	Re: Has anyone ever had an issue with using a 2 bolt main I think part of the reason 4 bolts were used in some applications was for durability/engine life like in trucks or marine engines. RPM ranges also come into play here too. Stock/Sprint car/endurance racing where you are off and on the throttle constantly tends to want to stretch the cranks. Using a 2 bolt crank in a low RPM NHRA Stock class car equipped with a Small Block Chevy engine where the engines are not running extremely high RPM (like over 9500-10,500 or maybe more) in most cases would probably be sufficient. Yes for the added insurance that a 4 bolt offers it's probably worth the extra $$$, but to just go out and build a 4 bolt from the get go for a 6800-7000+ RPM short burst engine might not justify the extra cost but you can always convert the block from 2 to 4 (if the rules allow it) if you feel you need a to. my 2 cents worth FED387