I'm thinking about using SRP pistons with Eagle H-beam rods I'm installing a 250 blower that I'm getting a chiller for looking to push 5psi, now the motor has about 500-550hp would like at least another 100 also what comp. pistons should I get boat is always trailered and only 93 octane goes in or better on rare occassion I usually cruise at 3500 but would like to be dependable at 4500 cruising and for a few minute bursts of 52-5400.

At 5psi and 93 octane and 650 horses, you can get away with standard flattops. If you are buying pistons anyhow, get dished blower/turbo pistons for an installed cr of 7.5:1 and pulley her for 7 psi. You'll still be safe (spark plugs 2 heat ranges colder).

JE makes a good blower piston, and so does CP either would work on a combination like yours.

thanks guys

What size engine?

J&E, Ross and BRC are all excellent pistons. MAny others also.

For standard bores and rod lengths TRW makes a good forged piston that is coated.

I used Wiseco, I beleive that's the co that Merc HP uses also.

it's a 502

502's come factory with forged JE flattops.

I built my blower motor from a stock 502 crate engine.
I called J & E and gave them the piston part number. It was okay to cut the dome off. I had the engine machine shop cut the dome and I lowered the compression to 8.0 to 1. I had no problems with this.
The only thing is, I wish I had left the compression up at the stock 8:75 to 1. The 250 blower has to be spun with the small pulley to get boost up. I had rather leave the compression up and turn the blower slower and cuts down on the heat.
I ran the 250 at about 7 1/2 #/s of boost on pump gas without any problem

SpeedPro also offers some excellent pistons for blower motors, L2513F, which is a 4.500 bore size, 695 grams weight, and 8.61 compression with 119cc heads. It's equivalent to the JE #106906 pistons that are in my 509 supercharged 509 engines. By the way, mine dyno'd at 644 hp@5400rpm, 5 lbs boost, just before I disassembled them for a ring and bearing job.