I have a 2001 358 with 500 EFI,s with ZX drives. Speed now is 78mph at 5200. My question is I have a set of Custom built 509's that put out 600hp at 5500 rpm,s just sitting in my garage collecting dust. The 509's have all the goodies to bolt right up with out too much modifieing. Also the 509's have just been rebuilt 0 hours, about 135 hour's on the 500 EFI's. I'm thinking about installing the 509's instead of rebuilding the 500's next year,

How much of a speed gain might I see with the 509's over the 500 EFI's. Also I might add the 509's are a much better built motor with the exception of the Fuel Injection on the 500's the 509's are Carberated.

So if anyone has any suggestion or opinions please let them FLY!!

Yeah....Pull those worn out 500's and sell me the set for $10,000.00. Then you can run the real motors that you already have. I'll even come clean the dust off them for you!!!!

I would think you would get high 80's with 600's.

You will be in the mid 80"s. But watch your drives. The XZ drives may not last very long. You can rebuild them with stronger parts. Max Machine Worx uses a stainless tower that they insert into the case that keeps the upper and lower halves from twisting,their bearing cap(top of the drive) is made from a billet piece that is almost two inches thick which also has a stainless insert, They also make stronger gears and shafts.They offer a one warranty on the drive if they do the mods.Here is a photo of their modified drive.

NJSONIC how much was it to get that done?you sent them your drive?how long did it take them to do?thanks,dave

Prowler,
The drive was done before it was mounted on our new Sonic. I really don't know the upgrade price but call Jason or Aaron 1-928-505-7860. Max Machine Worx will be at the Miami show. From what I have heard they will be in the Doller Offshore booth.They are going to be showing their new drive. I think it will be a 100% billet case. They have some of their drives holding up to 1200hp. I was shown some info proving their claims when I was at Sonic two weeks ago. Hope this helps.

Gerry, I think you will see at least 105mph out of that combo if you keep the wife and the new puppy out of the boat. You know, the weight issue! HA HA Don't tell Sue!!!!!!!!!!!!!!!!!!!!! Enjoy the new rug pisser! Wrink

Yea, put the 509's in and rebuild the 500's. They may come in handy someday.