A thousandth too small on exhaust valve clearance can turn your $30,000 motor into a pile of virtually worthless scrap metal in about 3 seconds.

Where did I said they were Marine engines? Oh, I didn't...

Someone above questioned whether or not anyone was building engines without human hands on them. I offered a data point nothing more nothing less. And I'm 100% sure they knew exactly what plant the were in and what product they were looking at.

Again guys,, good stuff. But I'm getting more confused by the minute.
My problem. Getting new 525's from merc. for about $21,000+- (at least that's what I hear I can get them) or custom/semi custom new built motors. The custom motors would be from a 540 block and about 560+ HP and $18,000 (no headers)
Which way to go ? :mad: I might post a question thread on this.

As we have spoke on the phone, You are trying to compare a Mustang to a Ferrari . The right builder is either going to make you a happy camper or not.

Thanks, and I understand, but here's the problem.
Custom motors... location.. warranty.. rigging and aligning drives,, bu.. t more HP. unique etc.
Merc. less HP but no other issues. $'s are close.

Good thread and great info as usual guys - thanks

Seems like - if all you want is reliable 450-500HP that runs on pump gas a set of factory new 502s with decent exhaust and maybe a little head work will get you there....reliably. Add in some oversized coolers, oversized oil pans, synthetic oil, and closed cooling and you can get 500 hours between refreshes.
Does that sum it up for 500HPs?

Now if you want more HP - gotta go custom