this is a great post and right on with the casting numbers. the only thing i would add is a 817 casting is also good. the 509 casting i think no matter what you do they live on borrowed time

It's your $$ waste it as you please

If you just have one hole that took a hit to the wall and the bore is still std or .030, why not put a sleeve in and avoid the .060 over?

No i screwed up... he said this is a 4.155 bore which equals a .030 bore over on the block. SO... it will be 406. I have no idea how I got .060 out of this. My builder was laughing at me saying he would never use a 400 with 60 over on it, and he was surprised i didnt say anything to him when i was under the impression he was using a 60 over block. I look like a dumbSh*t i guess.

I've always heard the 509's were the blocks to use. Although they are two bolt, many splay the center three. Heard the four bolt crack in the web. Heard the higher nickel content rumor also about them.

the four bolt is the same in the webbing as the two bolt block. BUT the extra main bolt holes WEAKEN the webbing. the splayed bolts go into a diff part of the web and don't weaken it. when it comes to refresh time, just do the rings. boats rarely wear the bores much. they either break, or they get water in them and break. they don't very often live long enough to wear out. not even in the sportfish forums. especially not here.

boats rarely wear the bores much,please tell me whear you get this kind of false information,the fact is a marine engine is much harder on bore ware,espically high perf ones making good hp,this is due to the rpm,s being higher.espically engines with long stroke cranks.

I thought that was an interesting comment myself Mike.

Ive had many boat engines that needed bore jobs at 400 hours from the constant high RPM running and pounding doled out. (that was 3 seasons of use in that particular mill) BBC's are worse than SBC's in this regard.

I think a boat engine is subjected to about the hardest possible load you can put on anything- its like towing a trailer uphill with the brakes on every time you turn the key plus ad a batch of bad fuel every now and then from a marina.

I do agree with the statement on the block which is why I had my 406 splay capped where the tap goes into the thick part of the block at an angle.

Lots of great info being laid out here regarding casting#s

UD

chrisf695:

Don't be so quick to call yourself a dumbass. People with too much pride and ego to ask questions are the dumbasses!
Just remember that "Dumb Questions are easier than Dumb Mistakes!"
Good of you to ask the question, not to assume, and learn!

Best Regards,
Ray @ Raylar

Guys great thread,thanks for the reading.