So why did GM go to this new block and what as the advantage over the old gen blocks?
-That was what was in the market at the time.

I've heard the disadvantages that they are not rebuild able.
-They are but in a non traditional sense. They are different and the parts dont mix.

What's the consensus from the guys that have done mods like Raylor and others? Did it dramatically affect engine life ?
-I did a huge amount of mods to stock 8.1/496's. Big cam, Tyler Crockett heads, flowed intake, roller rockers. They lasted about 150 hours and imploded a piston. To be honest, I dont know if it was the piston or the valve. Or, the exhaust leaking. I dont know since all were evident upon inspection.

Raylar mods (for me) have been great. I did te 600 HO rebuild with a careful short block rebuild. A bunch of grumpy old men built the short block to Raylars specs, bolted on the heads and now they have 300 hours on them. I dropped the stock Merc fuel delivery and added an Aeromotive fuel regulator and Whipple ECU program. The O2 was good. I think that is the ticket, map the O2 and be smart and you will have an engine that runs well.

The Mods have only been out a few years so any longevity info would be great.
-No problems so far. Good reliability. Dyno at 630 HP

I was not impressed with the one I was running as it experienced multiple sensor failures over and over.
-Maintenance and own a scanner. Fix or replace the bulll**** that doesnt work.

When used in Parasail boats , even with exceptional maintenance (everything must be entered in log book as per USCG regulations) the sensor failures always seem to take place at a bad time. Usually with 2 or 3 people harnessed to a Parachute on a 1000ft of line at least 500ft to 800ft above the deck. In Guardian mode , boat starts getting dragged backwards and hydraulics cant build enough pressure to winch people back down. One of my Captain's azzhole puckered so bad , it pulled the vinyl off his seat. If using gas , 502's work best in this application.
That said , I had a 496 with 2000+ documented hours that ran fine ( good oil psi , power , ect) that I sold for $3500 to a guy that exports them to Germany. He scanned it and wasnt concerned with the hours.


2000+ hrs equals about 1 1/2 years...

[QUOTE=PARASAIL941. the sensor failures always seem to take place at a bad time. Usually with 2 or 3 people harnessed to a Parachute on a 1000ft of line at least 500ft to 800ft above the deck. In Guardian mode , boat starts getting dragged backwards and hydraulics cant build enough pressure to winch people back down. One of my Captain's azzhole puckered so bad , it pulled the vinyl off his seat. [/QUOTE]


We had this running Joke out on the Outerbanks where your flying in 2o-30 mph winds

You know why Paasail Captains have such Tight Azzes. Than you look up 165 degrees and Quiver.