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-   -   353 Fastech N/A or Blowers (https://www.offshoreonly.com/forums/formula/362418-353-fastech-n-blowers.html)

F-2 Speedy 08-14-2019 07:57 AM

I think your budget will determine the route you take, if your goal is 600 hp Id build what you have with cams and heads and the Holley HP EFI and carb TB.........jmo

Mtb_05 08-14-2019 08:15 AM


Originally Posted by TomZ (Post 4701960)
If you’re concerned about drive longevity, then 600 NA is your friend.

600 NA isn’t too hard to get, though you’ll need to figure out top ends. 540s could get you there with the iron heads you have (assuming a mild 1.1 HP per cube). Change the rotating assembly, clean up the heads, and update the cam. You’ll probably get to your goal without much effort.

I want to do the same for my 311, though I’ll probably go one more season on the 502 MPIs. I’ll be watching your thread!

I’m leaning towards the N/A route. Mainly because of my drives. To much coin to re rig in one shot. The more research that I do on blowers I’m finding that I really should be looking at the 671’s and not the 250’s or 177’s. Now it’ll be finding the right parts to get an honest 600HP to the prop.

snapmorgan 08-14-2019 08:53 AM

Going from 500hp to 600hp is such a small step that you will hardly notice it on the speedo. I wouldn't get caught up in the number. I would build them for reliability and go boating.

Mtb_05 08-14-2019 09:19 AM


Originally Posted by snapmorgan (Post 4701969)
Going from 500hp to 600hp is such a small step that you will hardly notice it on the speedo. I wouldn't get caught up in the number. I would build them for reliability and go boating.

Factory hp500’s are 470hp. This will be a 130hp per side increase and a total of 260hp. To me that’s a huge difference. Should be a 7-12 mph gain. If you read my original post my motors are rebuilt and refreshed with low hours. This is strictly going to be for more reliable HP.

MR.HAPPY 08-14-2019 09:35 AM

600 per side will make it a 90+ mph boat...

Mtb_05 08-14-2019 09:50 AM


Originally Posted by MR.HAPPY (Post 4701976)
600 per side will make it a 90+ mph boat...

My current setup i’m running an honest 83mph right now @5300rpm’s. If I saw a true 88mph+ aftet builds be happy with that.

dennis r 08-14-2019 02:35 PM

what kind of speed did you see Apex

Baja Rooster 08-14-2019 02:54 PM


Originally Posted by snapmorgan (Post 4701969)
Going from 500hp to 600hp is such a small step that you will hardly notice it on the speedo. I wouldn't get caught up in the number. I would build them for reliability and go boating.

This is my exact experience going from 500 to 600 in a 272 Islander. I’m still breaking things in and haven’t played with props yet though. It would occasionally struggle up to 63 in perfect conditions and will now hit that much easier and quicker but will be surprised if I see 65mph. I consider this the limits of the boat itself though.

And here we’re talking about 100 per side for a 200hp increase. That should be noticeable and 600hp NA is pretty reliably obtainable.

A “reliable” build here may be taking the drives into strong consideration.

jwurl 08-14-2019 03:11 PM

No problem getting 700+hp out of a mildly built 540-572 with the correct parts. I have a 713 hp fastech 271 with a slightly built xr that I have been running for years with no problems. Just be easy getting on plane and don’t launch it and they will last a long time. Stay away from the superchargers, you don’t need it. Jeff Wurl

Mtb_05 08-14-2019 03:30 PM


Originally Posted by jwurl (Post 4702030)
No problem getting 700+hp out of a mildly built 540-572 with the correct parts. I have a 713 hp fastech 271 with a slightly built xr that I have been running for years with no problems. Just be easy getting on plane and don’t launch it and they will last a long time. Stay away from the superchargers, you don’t need it. Jeff Wurl

Thank jwurl. I’ve been told stick bravos are good to 600hp. Like you said roll on the throttle and throttle off if you happen to exit the water. I’m running labbed 4 blades now. Not as much of a bite as 5 blades. Now to find the right builder on the east coast.


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