Just thinking about it. I have 1" spacers to use already but this HVH super sucker makes come crazy hp claims. Anyone use them? Do they actually work or is it that same general idea as the 1" spacer you can get from mr. gasket at 1/4 the price???

They do work if you have a mis matched combo. If your intake, heads, cam and carb are all optimized to work together, it won't do much. My 383 with a RMBuilder cam only picked up 4 hp wiht a 2" and 2 Hp with a 1", but my combo was pretty spot on and I was really getting the most out of my heads. They did more for my low end torque than anything.

I picked up a 10th in the quarter mile in my 4000 lb lemans with a 468 pontiac. 11.60's to 11.50's

I wonder if it is a more hp application + higher gain kind of thing or what?

I guess I am asking if it is worth buying them for the boat or is this a hp gain that would equal nothing?

No, it's as I described. All it is really doing is allowing for an increase in the airflow velocity. In a properly matched application like mine, I'm already about max for velocity in my ports. A lazy (i.e. overly big) port will pick up much more.

I used a 1" 4 hole tapered Phenolic spacer from JOMAR Performance. It boosted the low and mid range torque significantly, even my daughter noticed. I'm running a 522 with 550+ hp at the time. Best $50 bucks I've spent.

Interesting...no these spacers won't make the carb height to much on an intake like an hp500?

The theory behind smoothing airflow and increasing runner length really helps to increase low end torque. If I was running a carb setup I would give one a try.

If I was running a Nitrous setup I would absolutely run one! Let us know your results.