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Need help with 454

A

ak375hh

Well-known member
I have a 454 on my 18’ airgator hull It does run some ground, but not like i want it to. I was told it was based off a 425/454ho when I bought the boat, but the pitch of the prop and the rpm doesn’t seem to coincide with 425 horse. I do not know the cam specs. I did a compression test and will post a picture with those results. It has flat top aluminum pistons and a set of 781 heads with oversized exhaust valves. Stainless 1 piece valves, hardened seats and good dual springs. It has a 78” 3 blade power plus set up with a 2:1 belt currently, and like I said it pushes through some ground ok but I bought the boat with the intent to make it run ground well. I’m wanting to know if this motor is ok to bump the power up in, or what your opinions might be?
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I should also ad it spins 4800rpm wot this way. And the oil pressure is good 60 at idle and runs up to 80-90 while running. I guess what I’m wanting to know is this motor worth putting money into...
 
It’s all about the boat set up when i got mine it wouldn’t run the ground at all i tweaked the hull and before the engine blew i could pit on the trailer with 4 ppl and hunting load. It’s all about the set up
 
How does the bottom of the hull look? If its flat or cupped you'll have problems running ground. It really helps to have a slight bow to the bottom so you can rock it slightly when it's on hard ground or concrete.
 
The bottom of the hull is straight. I did put a bow in it just in front of the motor stand. I do have a set of S blades and a 2.3 pulley that I’ll be able to try and purchase if it works out. I am looking at some cam/head/piston combos that would put me in the 450/500 range. Or would you think just buy a whole new engine? Obviously I want to take the route that doesn’t waste money, or spend more than necessary.
 
I did look at Superchargers for the 454. Does anyone have any reason why that wouldn’t be an ok idea?
 
In general terms the engine you are pairing it to should be a lower compression build and would be best to have forged pistons.

Can you slap a Pro-Charger on and push a low boost say 3.5psi....probably

We are back to the purpose built part of the game as supercharged engines normally run different clearances to prevent ring breakage also.

ps: S blades are the shizt, we love them for big heavy powerful boats
 
I did get the s blades on a killer deal. I’ve got the big and heavy part down! Now I’m working on the powerful haha
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Did go out again yesterday.
 
Crowhater

Oh where oh where has the Crowhater gone?

Anything Marshall has or had saw EXTREME duty. That dude had haul ass offshore sport fish boats, corvettes, airboats

I just asked about him the other day so it's sort of ironic you dropped his name Mike.

If it had a rev limiter Marshall would find a way around it. Dang I miss hearing his exploits.
 
So, I bolted on the s blades to try them out. I don’t have the 2.3 pulley yet so I tried it with the 2:1. It would only pull 3000 rpm on the 2 mark on the trailer. I re-pitched to the 1 mark but haven’t ran it yet as it’s 9:40 at night and that’d be a bad PR move out there. In the neighborhood. I’ll see what it does on the 1 mark tomorrow after work.
 
It takes power to spin them up but they push like a bulldozer !

Did I mention that my old 542 Cadillac spins 4 of them at 2+ :stirpot:
 
The s blades are 80”. There were 2 motors mentioned to me last night that are for sale. Alum top end 502/502 w/efi and an LS3. Both marine power engines. 502 being cheaper obviously. So those are possibilities as well.
 
2.3 gear and 3 80 inch s blades are perfect for a 454 but you need a lil more power. As mentioned,look up crowhaters budget 496 build,that will give you what you need at a reasonable cost.
I run a 454,stock steel crank,7/16 gm dimple rods, JE flat top pistols custom FELBER cam and head work. Edlebrock intake and holly 750. Im right at 550hp Gear box and 3 s 80 inch blades past the 2 mark. I've got like 8 years on the motor so far and it's still running strong!! It will go where I want and some place I shouldn't. Even pull an aircraft boat up the hike on 40 canal that sank. My boat is 14x8 but I have no doubt it would push your hull
I broke a 2.3 gear box and when I bought a new one went 2.68 when it was all the rage and can tell you first hand it's the wrong box. 2.3 is the way to go.
 
I was looking for his build and couldn’t find it. I saw one that was kind of vague. Didn’t give any part numbers or anything. Just prices for what he paid for some components.
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THEY LOOK COOL THOUGH! too bad I can’t spin them yet. #1 mark went about 3500.
 
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