Best heads for Gen VI 540's???
 

started as 502's. looking to gain some hp. currently have stock gm 088 heads. what heads are a direct replacement meaning same holes for accesories and same exhaust port height so my exhaust still fit??? also what size heads should i go with????

I run Edelbrock marine aluminum heads. They don't flow very well out of the box, but can be fixed. I spent some money having them ported and like the fact that they are hard anodized for corrosion and everything bolts up just like the stock steel heads. CP Performance has a good price I believe.

If you want to stay with steel heads, do a search here. there is a company that makes steel heads wher everything fits like stock, but they flow almost as good as Darts etc. I wish I could remember the name. If I do I will check back.

would like to go aluminum, just dont want to have to move all my accesories and then not have my exhaust line up because of raised ports. also, what size heads should i go with?? also arent the edelbrocks what the 525's run??? heard something weird about having a different exhaust bolt pattern or something???????

If you want aluminum, most of the heads on the market now have raised ports. There are a few that still have stock port locations.
The Edelbrocks do have a stock port location. The heads with the odd bolt pattern are the ones for the 525. The aftermarket heads you would buy will have a standard BBC exhaust bolt pattern.
All of the heads out there will have the same bolt pattern on the ends of the heads for your accessories. It doesn't matter which head you buy, the accessores will bolt up.
You can also get just about any head with Hard Coat anodizing now. If you are running in salt water at any time, that would be a good investment. Depending on the head, it will run $100-$200 to have a set hard coated.
If you went with a port that in only raised .200-.300, you wouldn't even notice it in the exhaust. It would only move it up about .150" and out the same amount. That's just over 1/8". The only way you would have any problems is in the middle, between the engines. If the headers are touching or just about touching in the center of the boat, then you may have problems with a raised port. The amount the port is raised will vary from head to head, but can run from .200-.600".
As far as which is the best, I don't think you would really notice much of a difference from one head to the next with your setup. I personally prefer the Brodix heads after some back to back testing with them. I like them so much that I pretty much stopped dealing Dart and became a WD dealer for Brodix. I can and do still use heads from Dart, AFR, World (Merlin), Canfield, etc. Any of the above would be a good choice. Size really depends on exactly what you have and what you are looking to make for hp. You also need to consider what your plans are in the future. You may end up with a head that is a little big now, so that it is sufficient in the future for upgrades. Think about your ultimate goals with the engine before you choose a head.
Let us know what your setup and power goals are now and in the future and we can recommend a good choice of head. Good luck.
Eddie

thanks eddie appreciate all that info. The engines when done will be 540's w/1050 doms, 9.5:1 comp, madera cams set-up to run about 5800 max rpm. If I could get 700hp out of the engine that would be plenty. basically the heads are my only variable left.

What heads did Bob design your cam's for? In my experience he doesn't just grind a generic cam, he takes everything into consideration in order to optimize the whole package. You should talk to him about heads, he has great prices on those too. My 2cents.. you can't beat AFR for power per dollar. Out of the box I'd put them up against any head out there..

im going to run my heads which are 088's this year, but hes grinding the cam knowing that I will be upgrading next year.

Always heard good things about the Brodix. I had a 540CI, compression around 8.5:1, merlin 345 iron heads, dart single plane intake, 1050 carb, crane 741 roller. It dynoed around 590HP or so. with smaller heads and more compression i think it would have woke it up.

Eddie, with the square port 088 heads on his 540, with a custom spec'd cam, and good intake, how far off his 700HP goal do you think he would be given the 5800RPM redline? And would it be worth it on those 088 heads to have a little work done on the exhaust side by a good head guy?

Im just curious as i've always thought of the 088 heads as a pretty decent performing head better suited on a larger CI engine vs the smaller 454CI. Of course if they are trashed then money well spent on new heads, but if they are in good shape, and if he wasnt planning to add a blower, would it be worth 4-5k for some new aluminum heads in his application? Bang for the buck wise...

i agree with you but i think i am at the point that now my heads are the restricting factor.

The 088 is actually a pretty good head. It has a fairly large runner for a stock cast iron head at 325 cc. As you mentioned, the short side radius in the exhaust port is where they need help. With some work there, a little in the bowls and port matching, then I would think the above combo could get to 650 hp or better at 5800. The best bet depends on economics. If you already have the heads and all of the hardware, then spending some money on port work is not a bad idea. If you have to buy all of the hardware, and then pay someone to port them, then it doesn't make sense. The hardware for the stock iron heads and a set of aftermarket aluminum heads costs basically the same. So the parts are a wash. The amount you pay for the port work will cover a big chunk of the cost of the new heads. You are only out the difference between the port work and the bare aluminum heads. A full, complete port job could cost $1000+. A decent set of as cast bare heads can be bought for about $1500. So, you could have aluminum heads for $500 more than you were going to spend anyway.
You would have to do some serious port work to overcome not only the larger runners in the aluminum heads, but the increase in compression that the aluminum heads allow. That's where the biggest benefit comes in. You can get more aggressive all the way around. More compression, higher cylinder pressures, more timing, etc.....all because of the higher dissipation of heat. That same 540 can now make well over 700 hp. You will also should end up with an engine that is safer do to the lesser likelihood of detonation.
Hope this makes sense and helps.
Eddie