Anyone try one of these? They make some pretty big claims of HP gains. According to the them, they will be in a Hot Baot tech article in a couple months. The spacer is 125.00, so I would like some input before I become a guinea pig. The guy told me about 14-16 HP on my 502 over any other conventional spacer.

I know a couple of guys that have tried these on dirt cars. They said they seemed to cleanup up the throttle rsponse somewhat but didnt really notice any gains in overall horsepower. Havent heard of anyone trying them on a boat or a drag car yet.

Hot Rod did a test several months ago with a bunch of different carb spacers. I think the most gained was something like 14hp. But there was really no relationship between the cost and fanciness of the spacer and how much power it made. Frankly, I'd just stick with a cheap 1" plastic 4 hole spacer.

The Super Suckers work very well, but here is the problem: A spacer is used to tune the combination, it will help break up the fuel, and more your power band up or down (depending on the style) So there is no end all be all that will always work better, it's a matter of what your combination needs if anything at all. I've watched a spacer pick up one motor 26HP, and put the same spacer on a similar engine and loose 5HP. The Super Sucker Style spacers (a lot of people make them) will generally increase the air velocity through the intake tract, (making the engine think you have a smaller carb, & intake) this will generally give you crisper throttle response, better torque, and move your power band down some RPM

The only way to know is to actually test it. Just like a prop on your specific boat, there is no end all be all answer.

In general do you think that 4 hole spacers are better on marine engines or open spacers? I guess that the Super Sucker is a third choice kind of open on the bottom and a 4 holer on top.

As a rule of thumb, I would never say any spacer is "better or worse" a spacer should be used as a tunning add, using the following guidelines:

As a rule of thumb a 4-hole designed spacer will increas the air velocity through the engine at lower speeds (can help overcome too large of an intake, cam, carb or too large of an exhaust) this will give you crisper throttle response, better low end torque, and will effectively move your power band down (100 to 300 RPM depending on the specifics)

Now an open plenum spacer will decrease your bottom end, and give you more top end (can help compensate for too small of a carb, intake, or cam)

Generally the thicker the spacer (1/2", 1", 2" etc) the more of an effect it will have.

Some of the split designs 4-hole to open can actually do both !

Bottom line if you have an idea of what you are looking for (more top end, bottom, etc) you'll have an idea of where to start, but it is trial and error.

will these simple open spacers do anyting for my stock 330's?
If I want top end power improvement at 4600-4700rpm

Man, you must really be worried that I will be faster than you this summer Rob!!!!!!

Canfield makes a 1 inch spacer that works very well, cost 50 bucks , and has shown 8 hp gains on almost every motor burke power tried them on, dyno proven, call him 513 942 5117

The four hole spacers also eliminate the the possibility of dropping a loosened base screw from your Holley into the intake.