Hey guys. I have a 500HP in my 280 Velocity and want to put a blower on it. My buddy had a Wieand 256 with dual 4's he is getting rid of so he can put an 8/71 on his engine. My question is, Can I bolt this blower on to my engine or will I have to change pistons and cam? I am looking to boost around 5psi with it. I believe that the 500HP is 8.75:1 compression?

merc 500 is 8.75 to 1 comp. mercruiser uses a 114 lobe separation on that motor. should be perfect for a blower.

Change the head gaskets too.

Don't go over 5 lbs. unless you add an intercooler or use really good gas.

Blown85,
I have a Darren Mayer Performance Enginnering prepped Mercury/Weiand256 and Whipple intercooler for sale off my 575 that I am having rebuilt as a 540.
I have the matching blue crank pulley and 2 or 3 blower pulleys. The Whipple intercooler is much lower profile (1 5/8"s) than the others and more efficient too. I paid $3000 for the Whipple and will sell the 256 and intercooler for $3500.
I am keeping the injectors. This will work well with carbs or throttle body injection.
Here's a pic.
Steve

HP500 has a 110° LSA. The 500EFI and 525EFI motors have 114°LSA.

True, but I don't think it has much more overlap than the EFI cams.

HELL OF A DEAL!!!

I installed a b&m 250 on my HP500..it is a 509 now...but I called crane to find out a good cam to put in it & they told me the stock cam was a good choice...110* is not ideal in my opinion, but it works fine..only problem I have is my knock sensor comes in around 4000 RPM...air is too hot and fuel aint good enough..I do suggest some sort of air cooling system...definately run the knock sensor system..but no more than 5.5-6 psi boost MAX!...no real need to replace the head gaskets..just make sure your water pressure stays below 20psi..and do NOT run a t-stat if you ditch the water pump and use a crossover..set timing @ 30*-32* no more

Hey Steve, Shoot me all the info on the setup you have for sale. What all comes with it etc. [email protected]