Anyone have experience using them, aftermarket flexo lite types or other brand. My 99 250 runs  a plastic oem fan never an issue but it is clutched. I am looking at a solid so faster rpms 6 k max. Thoughts on longevity?  I like the idea that when they break they will cause less damage.

 Think about it this way we have new heads to chose from that are stock replacement level incremented all the up to full race level. But for blocks we have full race only, in aluminum or iron. So if you don't want need that you stick with stock. So you look for hen's teeth or you deal with 40 over, maybe resleeve it.

I wasn't thinking of a block based off the current offerings that does seem silly. So I think there would be other differences, most cast iron aftermarket 427 blocks tip the scales at 250 lbs. that's what 50 lbs over stock? That 50 lbs is a turnoff for me when I don't need a block that will hold 1000+ hp. Make a 428 block with thick cly walls and some minor enhancements to have a reliable 600-700 hp range. Most guys on the street don't need more than 600. But stock blocks seem to be on borrowed time in that range.

So less material should = cheaper, but then I suppose there would be development costs. If you are targeting the mainstream then your sales numbers should be higher. How many people do you think we have on these forums? Now think outside the forum. Seems like 2000 should be attainable. Are FE powered vehicles really that small?

But this just me, just thinking out loud. Certainly far from an expert in this field.

Well this is really cool stuff for the folk with cash to play. How big do you think that market is? Me I'd rather see cheaper 427 blocks or hell 428/390 blocks. A lot of the junk us regular folk are playing with is getting tired and causing headaches and hard to come by. Would be great to pickup an new block for $1500. either stroke it or new style heads and the average joe would have a solid reliable platform. Plenty of power for the street. I would even prefer iron.

Dont get me wrong I am all for cool trick parts but the aftermarket for fe is getting heavy on the high end race pieces.  Would be nice to see some offerings for us regular folk. Plus it would seem that market would be bigger. 

That one oddly enough looked the best. All rockers tips showed a bit of wear but that one was extreme. It was also in the middle and not at the ends.

Yes running 80 jets for restrictors and a HV pump. Canton road race t pan so ~8 qt system. Everything I have read says restrictors are appropriate at this level. I could run without but I would fear flooding. I am running a solid flat tappet in a hyd block, passages not blocked.

As for coolant it was several years slowly getting worse running like that. Driven about once or twice  a month with 5-6 months hibernation in winter. Looking at the oil today I can see how it could cause lube issues on startup and even running that area is the least pressurized.

Not sure what else would cause it. To your point maybe a issue with rockers leaking oil but short of that one they all measure in spec. Unless the book is wrong and 4-5 thou is too much. Maybe restrictors are the problem.... Gotta take all of this down to the machine shop so I will discuss with him. Maybe he will see something I am missing.

Thanks Wes. So do you think that slow coolant leak could cause that kind of wear? I'm leaning towards that, but would like a solid explanation to know I've got it fixed before tossing new parts in there. Ill still spin the pump with the rockers off to be sure of that much, covered of course 

Talked to the machine shop about this and they pointed out leveling with a stack of feeler gauges on the China wall is a bad idea. Block is of unknown condition and likely no one took the time to make those square. So we shall see what they say after measuring again without leveling it.

Thanks for all the feedback guys, interesting to hear some real world feedback.

Okay so let's bump that rpm range to 2500 - 5500.  That leaves 2500 - 3300, which worries me that I will have a bog down low, that it will be sluggish off the light or out of a corner. Maybe it isn't worth worrying about but that is why I am asking here as I tend to over think things, a bit of perfectionist. I wish I had a dyno like Jay to do some real comparisons, but as you say I could swap out and find out. Wish I was quicker at these intake changes and had the time to do so.