Steve Zuckerman

Hello BobL and Dave, and anyone else that wants to chime in,
I will be adding aluminum heads to my motor, as well as new roller cam and ECU reprogram.
I have the cam (Comp) and ECU (AZSM) worked out. A friend with 575s did this mod over the winter and picked up 400 rpms, and lots of midrange acelleration.
The heads are another matter. I looked at a set of Edelbrock marine (hard anodized) heads yesterday, and for the money, they look like a nice improvement (flow and weight) over my HP GM iron heads.
I can get them for hundreds less than the Dart Pro 1 Marines, which were my 1st choice. Maybe I just don't have the right price yet on the Darts ? Bobl, are you a dealer for either? I can get the Edelbrocks for $1300 (internet), or $1500 locally. That's complete less springs, which I will be getting from Comp anyway. The Darts are $2000.
What do you guys think about the 2? Are the Darts worth the extra $$?
I am trying to make 825ish total horsepower (more is OK )with these modifications. I'm shooting for 90mph, and based on our formula (1 mph increase requires 17HP), it's going to take another 100 HP. Is this realistic? I've never dyno'ed the current setup, but based on stock HP, current mods and performance (85 mph), I think I'm around 725pshp.
Regards,
Steve

Nordicflame

Steve,
Just real quick a couple questions come to mind real quick…
Do you boat in salt water?
Is your blower up to the task?
Has chamber size on heads been considered for compression purposes? A smaller chamber would maybe get you up closer to 8.5:1 or so which would take some of the stress off of the blower at 7.5:1 and still be very safe with the aluminum. By running more initial compression you will require less boost to make the same hp.
Have you looked at Canfields?
Would you be willing to spend the extra $$ to have Jim Valako fully port the exhaust and assemble the heads?
Curious on cam selection…
Dave

Linster

The Edelbrock heads dont flow much more than the GM head unported. The Pro 1 flows much better and in my opinion is second only to AFR. AFR's are $3K.

GM
Lift 0.100 0.200 0.300 0.400 0.500
Intake 82 151 218 258 290
Exhaust 53 113 140 167 187
% Ex 65% 75% 64% 65% 64%

Edelbrock
Lift 0.100 0.200 0.300 0.400 0.500
Intake 76 146 210 255 290
Exhaust 70 132 156 181 207
% Ex 92% 90% 74% 71% 71%

Pro 1 & Iron Eagle
Lift 0.100 0.200 0.300 0.400 0.500
Intake 0 154 226 295 324
Exhaust 0 130 184 219 241
% Ex #DIV/0! 84% 81% 74% 74%

AFR
Lift 0.100 0.200 0.300 0.400 0.500
Intake 0 163 241 300 344
Exhaust 0 135 192 237 268
% Ex #DIV/0! 83% 80% 79% 78%

I used the Iron Eagle just because of cost vs flow. They flow the same as Pro 1

Good Luck

If you want I can email you the entire excel spreadsheet of all the heads I have had tested.

Steve Zuckerman

Dave and Linster,
Thanks for the input. Looks like this subject is like every thing else. You get what you pay for.
Dave, I have considered raising static compression with smaller cc heads, and I agree that would help. The Edelbrocks are 118cc. Stock ??
One of my local gurus says that smaller cc heads will offset the "open chamber" flow #s because they will shroud the valves. Your opinion?
Linster, Thanks for the flow #s. Sounds like you are happy with the Iron Eagles? I am going aluminum for sure.
As far as full port job, not at this time. Maybe when I stroke it to 540"s, which is a while away.
Not much of a saltwater boater, which I know opens up a lot more head choices, but I would still prefer the marine versions, just in case.
Re the cam, a friend of mine here has friends at Comp from his car racing days. They came up with a custom grind for his 575s, which are now running very well, and AZSM nailed the reprogram on the first shot. So I know that we have cam/ECU curve that works. The stock flat tappet is so mild, I know there is room for improvement. @ 5500, I'm probably already past it's peak efficiency. The only reason the boat/motor is still pulling is the additional boost @ rpm.
There may be better, but I don't have the information. Any recommendations?
Linster would love to see those flow #s! Send them.
Thanks again,
Steve

Nordicflame

Steve,
Some heads like the Canfields that are available with smaller chambers are available in a CNC version relatively inexpensive. This helps with the unshrouding a bit but IMHO with the boost the compression will be more important than the shrouding of the valves
I'm not pushing the Canfields but if you look at the flow numbers on the AFR site, there's no one close on the exhaust side for the $$$ and that's all that matters for your blower. This has proven true on the (almost) 100 mph Heat although the exhaust was worked over by Jim Valako and had Ferrea exhaust valves.
They do come in anodized and best pricing is from Competition Products.

I'm thinking that more compression is a must going to aluminum beings it effectively drops compression due to heat dissipation. 7.5:1 and aluminum would be pretty lazy. You'll want to get it to 8.5:1 somehow.

A cam with a compatible program is really good but does it match the head flow of the head used to select that cam? Maybe you should just duplicate your buddy's setup. Something "known" in this arena is always good.

Dave

Linster

I agree with Dave, get the compression to 8.5 or so and the blower will work less to get the same result with much less heat. After Daves remark, I do remember hearing the canfield offers a small chamber head. Use a cometic .027 gasket and you should be able to get there.

Steve,
PM your email & I will send it.

Steve Zuckerman

Dave,
I will check on the Canfields. Several of my old drag boat friends have used them and are high on them.
Looking @ Competition Products website now. Thanks for the lead!
Linster, I'm not shy , it's [email protected].
And thanks for your advice!
Regards,
Steve

bobl

Sounds like the guys have you on the right track. I don't think the Edelbrocks will get you where you want unless you send them to a good porter. If you're going to stick with a non CNC out of the box head the Dart Pro ones work pretty well, as do the Canfields. I agree bumping the compression would be the way to go. That blower will not support much more HP. It's kind of a catch 22. You increase the air flow through the engine with heads and cam, you will lose some boost. But you don't have a big enough blower to up the boost without really spinning it. So you'll make good power with less boost, but you may find the blower to be the limiting factor. Raising the compression may help. Just more food for thought.

I don't have a good line on heads. Comp products is an excellent source.