Fevre

See this come up every once in a while so let's settle this! Post yourpersonal experience with having an engine failure do directly because of main cap/bolt failure. Please no anecdotes of your brother's friend's cousin's father-in-law's uncle's engine failure just yours or your first hand account. I have none so I'll shut up now. BTW Please detail the circumstances and parts used.

71vettman

My 454 is a 2 bolt and luckily I have no main cap failure stories yet.
One of my main jobs at the machineshop I worked at was to tear down junk engines. I have seen alot of blown up engines the past 2 summers and not one was due to a main cap failure. Ive seen many other causes for engine failure though, especially broken rods and seized pistons. When I asked my boss if 4 bolts were worth it he didnt really seem to think that they were as much as they are thought to be. One thing he pointed out was that a 4 bolt main block is nearly identical except for that it has less material in the webbing due to the extra holes drilled out of them.

chewy

Friend has a long rod 427 2 bolt in a Super Comp car. The car through the lights at 9200rpm. With a set of studs no problems with the block in any way. BBs don't have main cap problems until they are really pushed hard.

PatsLs1vette

In my oppinion the 2 bolt blocks have thicker webbing.I have not had a 2 bolt block break a main cap yet.I have had 2 motors break main caps in our circle track motors from sudden stops at 100+mph into a wall,fixed that by installing billet splayed main caps.i spun my 2 bolt 327 to 7000 for several years before i broke a rod not any main caps.If your still nervous at least do main studs.

rrent

I've seen broken crank shafts, but never a main bearing cap failure. I think I read some time back - you really don't need 4 bolts until you are getting up in the 600HP range. Of course now-a-days you can order as much HP as you want and have it delivered ready to bolt in to your door - so 600 HP doesn't seem like so much.