Blower on a 454 makes a 525?
 

Someone said on another site that adding a 10-71 Littlefield blower to a beefed up 454 makes it a 525sc. Is the mercruiser 525sc not based on a 502 block?

Please give me your input.

Re: Blower on a 454 makes a 525?
 

NOPE !! A Mercruiser 525Sc is built on a 454 block. They use a Crane cam and springs and used a blower built by Weind I believe, and use a Dominator on top. A nice package built today would be a 4 bolt 454 with aftermarket heads, hydralic roller and a 256 Blower Shop blower. With this set up I have seen 575 hp thats reliable.

Pwrbt33
Offshore Performance
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Re: Blower on a 454 makes a 525?
 

a 10-71 will more than likely produce more than 525. I had a 454 w/174 B&M with cam and head work that made 560+ reliable HP.

Re: Blower on a 454 makes a 525?
 

I think a 10-71 is too big for a 454. I've got 10-71's on my 545's and had 250's on 509's. I'd call TBS and ask.

Re: Blower on a 454 makes a 525?
 

I believe the 525 is a 454/420 with a blower on it.

Re: Blower on a 454 makes a 525?
 

Merc 525 SC is a 454 with a weiand 177 blower, 7.5:1 compression, 4.5 lbs of boost 1050 Holley dominator carb. 91 oct.
Good motor, needed a bigger blower!. The 256 Weiand would be my pick.

RT

Re: Blower on a 454 makes a 525?
 

Firewalker, I am thinking of making 2 blower motors. If I have the 454/470 engines.If I were to rebuild them, and had Littlefeild 10-71 blowers, what specs would you go with to make the best combination for power.ie(lbs of boost,comp. ratio,cams,heads,lifters,pistons,crank)?

Re: Blower on a 454 makes a 525?
 

Yike,

I am an outboard guy, ask me questions there. I have a little knowledge with blower motors, but would not fell comfortable recomending anything, though I would think 10 71 would be big. 6 -71 would be better I think.

RT

Re: Blower on a 454 makes a 525?
 

jeeze I should check my spelling.......... oh well

Re: Blower on a 454 makes a 525?
 

no need to checl spelling.

the 525sc was a 454 with 177 blowe ron it. I have 454 bored 30 over witha 174 holley and 1050 dominator and its run very well so far and has been very reliable.

Re: Blower on a 454 makes a 525?
 

6:71 would work, but 8:71 would heat the charge less and fit just as easily as the 6.

Re: Blower on a 454 makes a 525?
 

Listening to all this information on the 454's with and w/o the blower, I am curious to know if anyone knows what a stock 454 with 420 hp actually had for hp realistically? How does this compare to the hp numbers of a 502/502 or 454/525?

Re: Blower on a 454 makes a 525?
 

I had a 365 ( 454 Mag ) that I had a B&M 174, with 5 lbs and a 1050 Dominator with Gil Exhaust and it made just under 500 hp........ DOH

RT

Re: Blower on a 454 makes a 525?
 

how many hours were on it when you installed the blower and how many more did it last? Tanx

Re: Blower on a 454 makes a 525?
 

I ran a motor that started out as a 330 and we changed heads to rectangular port GM heads with Inconnel exhaust valves and some port work. The block was bored 30 over and we used J&E blower pistons. I had a B&M 250 with a 850 Holley and a hyd cam shaft. Not sure how much power it made but I ran the crap out of that motor for about 3 years before I installed a 496. With the 330 the boat would run 61 to 62 mph after I installed the 460ci blower motor it ran 82 to 83 mph. After I installed the 496 it was a total terror, the boat would run 94mph and out run most of the hot rod out boards getting there. In my opinion a 10/71 is to much blower for your 454, by that I mean it takes a lot more power to turn a 10/71 vs a 250 or a 256 blower. If I were doing what you are doing I would sell the 10/71s and buy the Blower shops 256. Or build larger motors and use the 10/71's. Add a 1/4 inch of stroke and build a set of 496's :eureka:

Re: Blower on a 454 makes a 525?
 

Any idea how much power any of these engines made?

Re: Blower on a 454 makes a 525?
 

F377,

A 454/HP420 made 420 crank hp. Figure on eating up around 25hp thru the drivetrain and you get somewhere around 395 at the prop.

A 454/525SC made like 525 crank hp. Somewhere around 500 at the prop.

The 502/502Mag carb was 415 crank, 390 prop.

There is no 502/502 (except from GM as an automotive crate motor), but there were 502/HP500 (carb) motors. They were like 470 at the prop.

The 502/500EFI is also like 470 at the prop.

The 502/525EFI is like 500 at the prop.

Re: Blower on a 454 makes a 525?
 

I built two Ho425 crate motors with 177 blower and 750 holly's . The dyno sheet shows 536 HP at 5300 . This boat has been sold and still running strong 5 years of wide open throttle, The best thing the motors would idle all day long. They were in a 29 fountain and would run 83 on gps at 5300 with 28 hydros spinning in. The ticket would be blowers on the new 525efi.

Re: Blower on a 454 makes a 525?
 

The 525sc is a 454 with a 177 Weiand blower. Requires 92 octane. I have 2.

Re: Blower on a 454 makes a 525?
 

I am pulling the 454 mag in the Baja and replacing it with a 525sc next week. Here it is...it looks just like yours OkieTunnel. :D

Re: Blower on a 454 makes a 525?
 

You really need to decide how much HP and $$$$ are in the budget. Don't forget the drive train if HP and Torque go up so does the strain on the drive.

If you have the blocks and blowers already and need cranks I would go with a 496 combination. If you go with the 1071 non-innercooled and low boost I would say no more the 8.25 cr. Cams depend on budget if you want to go hyd roller or not along with HP you are looking to get. If you go with a blower and are not looking at max HP you have some flexibility with heads and cam set up also to save some $$$$. I think we really need some more info on what your final goal is to go futher. Last thing I have is do not get in a hurry and do the research it can save you $$$$ and some headaches. :D Just my opinions and I know nothing!. :drink: :drink:

Re: Blower on a 454 makes a 525?
 

I want to see 80 to 85 Mph and Have good reliability. My boating season up here is so short, I might only get her out 8 to 10 times a year thus no worries on mileage. She'll sit in the garage for the other 8 months of the year. I'm not running her pinned all the time either.

My total budet for engines is around $20,000. Not the largest,but it should be able to build me some respectable power.

Re: Blower on a 454 makes a 525?
 

Sorry I did not get what boat you have and size weight etc. What speed are you seeing now? That will decide how much HP you need.

I have stock 1987 420s with Gil Exhaust and TRS drives..would I be able to simply bolt on a set of B&M 174 Superchargers and use my olley 4150 750s I have on the boat now? Or is there some mods to the engine that needs to be done? I know I have rectangular port heads..Crane roller Rockers and hydraulic lifters which I believe all came stock in those motors! I like this thread..Im learning a lot and since my Port engine is out of the boat now I may pull the other and do the upgrades this winter!

I turned a couple of 420 in to 525SC clones, or Hawk 525SC some years back. I used a B&M 174 with a Holley 850, Imco exhaust and MSD Ignition. I used the stock pistons, new rings, bearings and inconel exhaust valves. Those engines were turn key, I never had any issues with them. I was running 4psi boost.
In your case you would need a bigger carb than a 750 and if you plan to use the stock ignition, you should get a V6 ignition module (less advance). This mod will add 80-100 hp to your 420s.