So he can give me a hard time, but I'm not allowed to tease back? Come on relax tkach, it was one de rail... Again, back to the original thread.

i have built many 1000 + hp engines with 4 bolt iron caps without any problems.of course i would rather a splayed steel cap but that,s not always in the budget.if that old iron block gets a good align hone with arp studs you would be amazed at the beating it can take.

ok,you are allowed one i guess,lol.

I needed to hear that at this point , thanks . Don't have money for a new block too . I guess I'll be safe enough at 850 .

is your block gen5 or gen6?

Lots of action here while I was at work today.. I didn't notice that SB posted at the same time as me, answering my question before I asked it.. Before jumping into main caps, it is the weight of the components the bolts are trying to keep from flying off the crank that is the biggest factor, and those pistons and pins get pretty heavy when they're changing direction at 6000rpm. Acceleration rate of the components will have an effect too, so not a bad idea to go a little overkill on a roots, or screw blown deal that can really zing the engine when throttling. The majority of rod failures I have seen, other then from being pounded apart by a damaged bearing, is during a burnout, or after blowing the tires off at the hit. I've seen a Ti connecting rod ripped in half from that too. So assuming we're good with accepting negative accelerative forces as being the big factor, I think that's the right term, basically when the crank's running away from the piston, that leaves HP out of it for the most part. I have personally never seen a rod bolt failure in a marine engine that could be attributed to the bolt itself not being strong enough, ever. I have seen lots of old blower motors running TRW paperweights, spinning 7000rpm on stock GM rods and bolts. Pick your poison, there's nothing wrong with running a stronger bolt then you need, we do it with a lot of other components, but at the same time, you don't need to spend a fortune on them either. Fatigue life will be a factor though in terms of $ vs. lifespan. To touch briefly on the L19's, the oldest set that I know of using personally is just coming up on four years. They're in a 850hp 489 procharged deal that runs no stat, and does a lot of boating in the salt. I will let everyone know if they suddenly become embrittled by hydrogen and cause a catastrophic failure.. That's pretty much the only way I know how to test anything.

Merc Racing prepped Gen VI .

During the early and expensive learning curve of tuning 1000hp worth of nitrous on top of a 1200hp engine, it became apparent that the billet caps would distort permanently after severe abuse, and take out the bearings, or even the crank. The Iron caps were, for lack of a better word, more forgiving (to really bad tune ups) and lasted all season no problem. I would run billet caps now at that power level, but I sure wouldn't be scared to run regular caps for your average 1000+hp marine deal either.

Did you choose the L19's mainly due to fatigue resistance, or was your main objective strength? Seems like the 2000 series bolts would have more than enough holding power for a normally aspirated 489 being spun at around 6500 max, unless you were planning to go higher than that. Just curious.

imo,the gen6 block is much stronger than the gen5.if you have your block align honed with arp studs you will be golden.