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You need to be sure about that piston clearance. The piston will be smaller than the 4.466 bore size. The cylinder clearance is built into the piston. You should measure the piston 1/2" above the bottom of the skirt. Service limit on those pistons is only about .005. Meaning, if you have more than .005 clearance, you need to bore and go to 4.500. Those pistons have a high silicone content and are designed to run fairly tight. They...

525SC is a 454 with a 177 blower and 1050 Dominator carb and Gil exhaust except the last couple years had CMI headers. 490 HP at the prop. Yes, the are quite a bit thirstier than a 502mag. They are very good engines. They do need 92 octane fuel. 325hrs???? It really depends on how it was maintained. It could be fine and could need some work. Salt or Fresh water??? The intakes do not like salt and they are very hard to find used. They...

What would everyone recommend if the motors in the boat I'm looking @ have ~350 hrs on them, be done to them. All I know is they are running well right now, but the future........ Thanks, Dean

I must be missing something, otherwise, it seems there would be some opinion, for or against using Compacted Graphite Blocks. Assuming CGI up-charge is only $1,000.00 over Grey Iron, that is somewhat insignificant. That is, if there are durability and mantainance advantages. Some show preference for a "used" grey iron block over new. Reason, the aged block has cycled through heating and cooling long enough that it has taken...

Quote: Originally Posted by blue thunder If you need any help or first hand direction let me know. I've pulled many a engine out of a hp boat. Glad to help. Dave Thanks for the offer, but im going to pull them tomorrow , not a problem doing it just wasent sure about bell housing.

Quote: Originally Posted by Dean Ferry JT, So you did the conversion from flat tappet, HR cam? What are the benefits in your opinion? Thanks, Dean I'd say it's where a majority of the power increase comes from.

Quote: Originally Posted by Throttle Fever Sounds like your tring to get out of turkey day at the in laws LOL Yikes!! You might be close. But really I just like this chit and the wife understands (usually).

Quote: Originally Posted by getrdunn Sounds like your going after that rough idle. Unless your going dry to the tips you'll for sure have reversion issues. Those Thumper cams were pretty much designed for the old muscle cars with little to no other good guy parts needed to achieve that desirable rough idle (King Of The Drive In). If you look at the seat timing and the tight lobe sep it's a given those cams are for one thing and one...

have a friend of mine that has a pair with over 600 hrs, just had a blower let go, had that redone and changed the valve springs, runs great....

I did what Ray had said I did drain the oil just oil Question if the tubes inside the oil cooler did have a crack wouldn't that fill the heat exchanger so when I use the blue pump anti freeze would come out.I also refilled the resivoir with antifreeze an its been sitting for 4 hours it went down 1\3