mjb

I'm getting ready to do a 500-540 HP program with my 502's. I run in salt so Aluminum heads are not an option(not sold on the long term reliability of the anodizing). I'm going either 320 Merlin or 308 Dart iron eagle. My cam is a 761. Any thoughts on the pro's and con's of these 2 heads???

articfriends

I'm currently running the merlin vr's (315/320 cc int runner). If you buy the vr's it is quite a good value because they come with inconel exhaust valves,good springs and titanium retainers,10 degree locks. The only bad part is the exhaust is raised over stock and can cause exhaust alignment problems and they don't flow all that much better than stock heads,have a intake to exhaust ratio around 65%,flow about 300intake at .600,200 exh at .600,Smitty

mjb

thanks Smitty- have you had any problem with the valve covers leaking with the merlin heads? I hear that the rail is so thin that there isn't enough room for the o ring gasket to seat properly. I've heard that this is also a problem with the iron eagles. Is anyone familiar with this? Is there an easy fix?

Airpacker

I pulled my 500 down at 300 hrs and found head gaskets going away and several cracks in the heads around the valve seats. The descision to buy new head was a simple one. I looked at price, performance gain and reliability. I ended up buying the edelbrock marine heads. The are hard anodized and come with inconel exhaust and stainless intakes but no springs and hardware. They should be matched to cam choice anyway.I had my engine guy clean up the ports a little before I installed them. I installed good felpro marine head gaskets and went to 1.8 to 1 rocker arms for a little added lift and duration(stock cam). Raised the fuel pressure about 3 lbs until I had a nice color on the plugs and it has run perfectly. One thing I found was the variation in factory compression ratios cylinder to cylinder. The lowest worked out to 8.56 to 1 and the highest was around 9.1 to one so I had the combustion chambers worked to give me exactly 9 to 1 on each cylinder. Without a remap I am hitting the rev limiter so I will need to do that over the winter. The motor picked up some serious grunt from 3500 up. Total cost was around 5000.00 canadian bucks but I did all the wrenching.

Nordicflame

I believe Innovation Marine did the DPX600 for Volvo. A Gen VI 540 with a single plane MPI system very similar to the Holley.
I'm sure they could help you out with some various choices.

Dock Holiday

A little disappointed with my phone conversation with Innovation today. Not sure if I caught them at a bad time, but they made me feel like they didn't really care if they got my business or not. And they quoted $3K more than I was told last week?

So I went to plan "B", and think this may be better than what Innovation was offering.

I just got off the phone with Tyler Crockett, http://crockettmarineengines.com.

It was refreshing to talk to someone that acts like they really want my business.

I have heard a lot of good things about him also and he offers a 500 EFI package that he as proven to be reliable. Funny, but he thinks differently than Innovation and says that a complete rebuild is probably not needed. He will do a leak down, but says that the bottom end of the 500's is very strong and he likes that I run the Mobile 1 15W50 and that I should not have to worry about the lower end.

He adds Brodix Aluminum coated heads with a very strong proven valve train. They work the heads in their stop on their CNC machines. He changes the cam, all new gaskets, reprogram the ECM in house, dyno and out the door in 2 to 3 weeks.

Heads $0000.00
Rework $ 000.00
Cam $ 000.00
Gaskets $ 000.00
Labor $0000.00
Dyno $ 000.00
_________________
Total $0000.00 per engine

I left the prices blank, but very fair in my opinion. Give Tyler a call if you want more details.

I really like this guy. He answers the phone and is very willing to tell you exactly what he as found to work and what he will do. He says they will dyno at 600 HP and I should easily get another 300 hours out of them.

Just wanted to share this with you guys. Thanks for all the good information