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

Mtb_05 08-13-2019 11:01 AM
353 Fastech N/A or Blowers
 
I’m looking for some insight on which direction to go for upcoming off season. Currently have carb HP 500’s. Starboard motor was a complete rebuild 15hrs ago due to broken oil pick up tube. Portside has 75hrs on topend and 340hrs on bottom end. Thinking about pulling motors this winter to repaint bilge and freshen everything up. This is where I need some input.

Do I (A) build current motors for a benchmark of 600HP N/A
or (B) keep my motors as is and add blowers? If option (B) which blower setup? Weiand 177’s or B&M 250’s which I was told you can’t get hard parts as they aren’t made anymore.

Currently have installed MSD ignition, Holley electric fuel pumps, water crossovers and upgraded Holley carbs.

badmonkey 08-13-2019 01:29 PM
IMOP build fresh 600HP N/A motors...simple.....

MR.HAPPY 08-13-2019 03:40 PM
Will be a fun boat with 600 per side!!!:ernaehrung004:

Apexwarrior 08-14-2019 04:27 AM
Mine came with 525's and I put Whipples on it the second season I had it.

They made it an entirely different boat.

The only drawback at all has been the drives. I had to accept a rebuild every few years or lay out $35k for Imco's and be done. I went with rebuilding them.

Mtb_05 08-14-2019 05:12 AM
Originally Posted by Apexwarrior (Post 4701946)
Mine came with 525's and I put Whipples on it the second season I had it.

They made it an entirely different boat.

The only drawback at all has been the drives. I had to accept a rebuild every few years or lay out $35k for Imco's and be done. I went with rebuilding them.
My drives are going to be my weakest point. You already have an upgrade with having 525’s. So I’m assuming you have XR drives.

Apexwarrior 08-14-2019 05:14 AM
Yes - XR's.

VoodooRob 08-14-2019 06:40 AM
Look into having your drives built at All American Drive Service. George knows every way to get the most out of a Bravo setup. Stage 4 is what I did behind 600SCIs with Stage 3 upgrade. http://www.allamericandriveservice.com/Hi-Performance.html

Mtb_05 08-14-2019 06:52 AM
Originally Posted by VoodooRob (Post 4701952)
Look into having your drives built at All American Drive Service. George knows every way to get the most out of a Bravo setup. Stage 4 is what I did behind 600SCIs with Stage 3 upgrade. http://www.allamericandriveservice.com/Hi-Performance.html

Thanks Voodoo, I’ll check him out

Nothing personel 353 08-14-2019 07:26 AM
Go without blowers my 02?

TomZ 08-14-2019 07:37 AM
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!

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.

Apexwarrior 08-15-2019 04:19 AM
I agree with Snap above. I don't see how 600 hp make it a 90 mph boat. Unless you put boxes and shorties on..

I run mid 90''s with the Whipples (750-780 hp) and nose cones on Bravos.

Mtb_05 08-15-2019 04:59 AM
Originally Posted by Apexwarrior (Post 4702099)
I agree with Snap above. I don't see how 600 hp make it a 90 mph boat. Unless you put boxes and shorties on..

I run mid 90''s with the Whipples (750-780 hp) and nose cones on Bravos.
As stated above. I’m currently running 83mph @5300 rpms. I’d like to think I’d gain 7+mph by building 600hp a side. That would put me at an honest 88mph ballpark.

snapmorgan 08-15-2019 12:04 PM
I took a 502mag MPI and added some Edelbrock heads and a cam and got 567hp out of it. Pretty much by upgrading your heads and camshaft, you should be able to get 600hp. I have a proven 700hp 540 EFI build recipe if you are interested, but the only piece you would be reusing is your blocks and would probably spend another 30K on parts.

Mtb_05 08-15-2019 12:29 PM
Originally Posted by snapmorgan (Post 4702201)
I took a 502mag MPI and added some Edelbrock heads and a cam and got 567hp out of it. Pretty much by upgrading your heads and camshaft, you should be able to get 600hp. I have a proven 700hp 540 EFI build recipe if you are interested, but the only piece you would be reusing is your blocks and would probably spend another 30K on parts.

Does it have to be converted to EFI in order for your recipe to be achieved?

snapmorgan 08-16-2019 10:17 AM
I am sure it would make the same power with carbs, but I have no idea if it would idle good enough for docking

snowrunner 08-17-2019 07:25 AM
Originally Posted by Mtb_05 (Post 4702035)


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.
A friend ran 5 blades on his 353 with 525's and boxes - snapped many drives. Moved to 4 blades and stopped the carnage.

offthefront 08-17-2019 09:16 PM
Originally Posted by snowrunner (Post 4702470)
A friend ran 5 blades on his 353 with 525's and boxes - snapped many drives. Moved to 4 blades and stopped the carnage.
Slip is your friend.....


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