CraZ28's Engine Build Thread
#21
02-22-2010, 03:12 PM
4. Two bolt Vs Four bolt Vs Splayed
Two bolt main blocks are more common and easier to come by. Many will even argue they are stronger than their four bolt counterparts because they take less material out of the web of the engine block. A two bolt also gives you the option later of installing 4 bolt caps or splayed main caps -- the strongest combination possible. Keep in mind there are significant machine shop labor costs using this option.
If you plan to exceed 400 HP with a small block or 600 HP with a big block, you should use a four bolt block.
If you plan to exceed 500 HP with a small block or 800 HP with a big block, buy a two bolt main block and have splayed caps installed.
Be careful with certain 4-bolt blocks before you buy them, especially the 400 small block Chevy. It is very common for these blocks to be cracked in the web area near the mains.
Two bolt main blocks are more common and easier to come by. Many will even argue they are stronger than their four bolt counterparts because they take less material out of the web of the engine block. A two bolt also gives you the option later of installing 4 bolt caps or splayed main caps -- the strongest combination possible. Keep in mind there are significant machine shop labor costs using this option.
If you plan to exceed 400 HP with a small block or 600 HP with a big block, you should use a four bolt block.
If you plan to exceed 500 HP with a small block or 800 HP with a big block, buy a two bolt main block and have splayed caps installed.
Be careful with certain 4-bolt blocks before you buy them, especially the 400 small block Chevy. It is very common for these blocks to be cracked in the web area near the mains.
#22
02-22-2010, 03:14 PM
#24
02-22-2010, 03:20 PM
No, I do know back in the day when real muscle cars were running around they used stud girdles! And my windage tray was cracked at the oil pump bolt so I think something flexed and broke it! I am not supercharging or using nitrous so I should be O.K.
#27
02-22-2010, 03:33 PM
nope...but i guess that's why i won't ever worry about my bottom end falling apart and you will be
#29
02-22-2010, 03:43 PM
callies dragonslayer...and i said i'm not breaking the seals on any part of that motor at this point. maybe next winter but not this year
#30
02-22-2010, 06:19 PM
It makes no difference on what the rod lenght is, however the wrist pin on the piston has to be moved closer to the head of the piston in order to keep the piston from going past the deck of the block and smashing into the heads. If you buy a complete rotating assembly, including pistons, part numbers will be different depending on rod lenght. The longer the rods the more the wrist pin will have to be moved towards the head of the piston. The crank will still be the same, except for balancing. You start running into problems when the wrist pin is moved into the ring land area, which can happen when using 6" rods.
If you ordered a complete rotating assembly everything should fit properly.
If you ordered a complete rotating assembly everything should fit properly.