speed on a 358 sonic
 

I just wanted to tell everyone my results, I have a 358 sonic with 496 ho in it, the boat would run 68 to 69 on gps. I removed the restitor plates and put 26 pitch props. the cruise speed went from 47 at 3600 to 53 and the top speed went to 72 mph.. I am very happy with the results I think I might try 26 labbed might be able to get another 1 or 2 mph out of it. What are the average speeds for a 358 with 496?? Is this good or can I get more???

Re: speed on a 358 sonic
 

I have a 358 with 525's and switched from 4 blade Bravo1's to Hydromotive 5 blades and picked up 2-3 mph. The 5 blades also made a drastic improvement in the handling of the boat. Madprops, what are the resistor plates that you removed and how do they effect performance.

Re: speed on a 358 sonic
 

So how fast are you running now ? and Cruise speed ?

Re: speed on a 358 sonic
 

82 mph @ 5200rpm's is the best that I have ran on top speed. I don't remember what rpm's that I was running at cruise speed.

Re: speed on a 358 sonic
 

I spelled incorrectly they are restrictor plates in the exhaust manifolds

Re: speed on a 358 sonic
 

how much effort is it to remove these resistor plates? 3-4 hours per motor?

Re: speed on a 358 sonic
 

I just spoke to my mechanic and he cautioned against removing these as these plates keep water from backfilling the motors

Re: speed on a 358 sonic
 

What size 5 blades did you go with ? and what size bravo's did you have ? I'm trying to figure out what the pitch difference is when you go to a 5 blade.

Re: speed on a 358 sonic
 

I have heard that as well but after removing the plates there is no way the plates woulf have prevented that, now the are use to prevent moisture but again I personally think that it will get in not matter what but I am not a mechanic

Re: speed on a 358 sonic
 

No it took me about 1.5 hour per motor