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Bbc blower motor help!
Currently running a 509 bbc with a b&m 250 blower, ready to do some upgrades and looking for advice on which way to go?!! |
You are going to need to be a little more specific on what you want and what your budget is to get any decent answers.
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Budget $10000 give or take a little, current motor was in the boat when I bought it and said to have 12hts since dyno fresh when I bought the boat, dyno 660 hp at 5lbs boost at 6100 rpm and was still climbing. Known parts list is gm block 509 cubic inches, dart pro 1 aluminum heads, crane gold rockers, unknown cam assuming decent size as it was still building power at 6100rpm, b&m 250 blower with intercooler, twin 750-850 carbs with Nickerson stickers on them, msd ignition. Was thinking I’d do leak down and compression test first along with pull timing cover to research cam per number, then assuming the cam is a good blower grind move up to a 1071 intercooler and twin dominators setup. Or option #2 is a motor for sale locally it consists of a new gm block setup at 540 cubic inches 8.5-1 has eagle crank and rods floating pins je pistons, afr 357cc heads, Jessel shaft mount rockers, solid roller cam haven’t seen cam card but assume it would need switched out to hyd roller marine grind, has 871 blower shop blower and intake with dominator carbs has brass freeze plugs and marine grade head gaskets less than 500 miles.. Can buy it for 15000 or less Motor #2 seems to be the way to go, after selling current motor it puts me in the upgrade for 5000 give or take and with a 540 vs 509 also has a lot better hardware afr vs dart heads, shaft mount rockers, bigger blower and carbs ect, it can be bought for 15000 or less and after selling my current motor has me into the upgrade for 5000 plus any parts needed to make it boat friendly, besides a possible cam and lifter swap what else would need to be done to motor #2 to make it boat friendly?? Does a boat motor have different clearances on valves, bore, and lower end bearings than a car motor? Seems if I buy a blower for my current motor I’d have around the same investment with less cubic inches, less cylinder heads ect?? |
Not sure of all your internals, but I had a pair of 509's. Dart Blocks, Dart Aluminum CNC Heads, T&D Rockers, Crane Cam, Callie Rods and Crank. 10-71 blower shop, Intercoolers, msd, And my first pulls with 7lbs of boost made almost 980HP at 6000. I detuned them to 5lbs of boost, 5600 RPM and they were making about 875. Reliable. I am no expert but block geometry is better on a 509 then it is on a 540. I have also had 540's but they were NA.
Seems like your base motor Idea is the way to go. but LOTS OF VARIABLES in your ideas. |
I’m looking to make 850-900hp on a safe tune and have reliability that will last several seasons without a lot of maintenance? If my heads are just factory castings is that an achieve able goal?? |
Originally Posted by Daytona25
(Post 4653876)
I’m looking to make 850-900hp on a safe tune and have reliability that will last several seasons without a lot of maintenance? If my heads are just factory castings is that an achieve able goal?? |
Nice heads rockers and pistons in that 540. Could use more blower but sounds like a nice setup. A blower swap on your motor would be pretty simple too. |
I was just thinking the 540 seemed like a better package all around and possibly the better deal $ wise if I sell my motor complete to return most of the purchase price vs spending the money it would take to swap mine to larger blower and carbs and all. |
My opinion, more cubic inch in a boat, I would go to the 540.
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Kinda what I was thinking along with better flowing heads!! |
a 509 with a decent head&cam package and an 8.71 with a pair of 850 carbs will easily make 850 reliable hp.if starting fresh with no parts go with a 540,if you already have a 4 in stroke crank go 509.the power output is pretty close on both combinations.
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Originally Posted by Daytona25
(Post 4653908)
I was just thinking the 540 seemed like a better package all around and possibly the better deal $ wise if I sell my motor complete to return most of the purchase price vs spending the money it would take to swap mine to larger blower and carbs and all. IMO, you'd prob get closer to 7-8k for your 509. With those numbers you'd be at 9-10k out of pocket. If you sell your 250 setup and swap to bigger blower, you could probably keep it to around 5k out of pocket. Now, do you have 15k for a drive that will last behind it??? |
It’s goin in a 25’ Daytona with a brand new hp transom assembly and new built xr upper with a bmax 2” shortie lower all new from bravo shop last season. |
A turned up little motor or a moderate bigger motor making the same power, which one will last longer, which one has a better chance of detonation.
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Originally Posted by GPM
(Post 4654007)
A turned up little motor or a moderate bigger motor making the same power, which one will last longer, which one has a better chance of detonation.
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Originally Posted by Daytona25
(Post 4653992)
It’s goin in a 25’ Daytona with a brand new hp transom assembly and new built xr upper with a bmax 2” shortie lower all new from bravo shop last season. |
Mike Tkach what speeds do you think 850hp will put me at, 105-110? |
im not sure but a oso member [the deep] has a 25 warlock with a 509 i specked for him,your boat should run almost the same as his.maybe he will chime in on this one.i had a 26 american offshere with a little more hp and it did 106.it was almost 900 hp.i destroyed a standard brave in short order and replaced it with an xr,it was still on the boat a few years later when i sold the boat.
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So I should be ok with the xr and bmax lower then mike?? |
Also do you recall what drive ratio, prop, and rpm you were runnin on the American offshore?? |
The center pod of the Daytona is raised higher than the Warlock or the American Offshore. 1000 HP and a -2 should get you close to 120 mph.
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Originally Posted by Daytona25
(Post 4654032)
So I should be ok with the xr and bmax lower then mike?? |
Originally Posted by Daytona25
(Post 4654033)
Also do you recall what drive ratio, prop, and rpm you were runnin on the American offshore?? |
Originally Posted by mike tkach
(Post 4654026)
im not sure but a oso member [the deep] has a 25 warlock with a 509 i specked for him,your boat should run almost the same as his.maybe he will chime in on this one.i had a 26 american offshere with a little more hp and it did 106.it was almost 900 hp.i destroyed a standard brave in short order and replaced it with an xr,it was still on the boat a few years later when i sold the boat.
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That’s a lot, 660hp currently I’m turning a 1.5 ratio and 30p bravo 4 blade 5600....I didn’t think 850 would let me step up to a 1.36 ratio and keep a 30p or go up to 32p the extra power must really wake these boats up!? |
So I found a good deal on a new 871 which for my 509 is sized appropriate, is there a difference in performance from a billet blower shop blower to a Weiand?? Also with a 509 and 871 would I benefit to move up to dominator carbs over the 750-850 carbs I have now?? |
Daytona - I have a 2001 26 Daytona and running 650 HP and -2 imco lower the boat ran 94 MPH best 90 to 91 anytime. That was with a 1:5 ratio and a 28 pitch Bravo 4 blade.
Today I am running a 598 NA at 800+ HP at 112 MPH anytime. that is with a 1:34 ratio -3 IMCO lower and a labbed 28 Bravo 4 blade at 6100 RPM. My propshaft is 2 inches above the lowest point on the hull. |
Originally Posted by Daytona25
(Post 4657593)
So I found a good deal on a new 871 which for my 509 is sized appropriate, is there a difference in performance from a billet blower shop blower to a Weiand?? Also with a 509 and 871 would I benefit to move up to dominator carbs over the 750-850 carbs I have now?? |
That seems like your prop is really shallow, I have a -2 lower I’m about 2” lower than rub rail at top of drive and still 2”-2.5” below the bottom, I’d think at 2” above the bottom the boat would just cavitate and not plane out?? Mike I’m leaning towards a billet blower shop blower I was assuming they would make the best power out of them all and they look a lot better imo was thinking the 3 circuit dominators would have the best tuning capability but the 4150 1050 would allow me to keep my flame arrestor and stuff I already have! |
So I found my dyno sheets and original paperwork for my current motor also decided to keep it and ad the 871 billet blower shop blower with blower shop intercooler do these sheets give us any valuable information about current cam ect??https://cimg0.ibsrv.net/gimg/www.off...e7c35f807.jpeg |
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That dyno sheet looks Rich on af. |
Originally Posted by Daytona25
(Post 4653992)
It’s goin in a 25’ Daytona with a brand new hp transom assembly and new built xr upper with a bmax 2” shortie lower all new from bravo shop last season. |
I’m more wondering what is causing the dip in power above 5300rpm, is it a cam or blower restriction??
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Second wind I’ve heard that, and also heard a lot of people have fairly good luck with xr in smaller cat with big power if you drive it right?! |
Daytona25 - before i cut the hole and mounted my neutral extension box I called Eliminator and asked them what the IDEAL height for the prop was for max speed.
They told me 2 inches up from the lowest point on the bottom of the boat. They also told me the boat would be a challenge to get on plane. But with some Tinkering I was able to get the boat on plane without much trouble. With a Bravo 4 blade prop. |
Originally Posted by 14 apache
(Post 4669191)
That dyno sheet looks Rich on af. Needs wideband.:) |
Originally Posted by SB
(Post 4669303)
Most dyno's do when using airflow vs fuel flow for AF. Waste of time, Don't know why the dynos are even set up this way since this way of doing AF is always way off..
Needs wideband.:) |
Originally Posted by Daytona25
(Post 4669237)
Second wind I’ve heard that, and also heard a lot of people have fairly good luck with xr in smaller cat with big power if you drive it right?! |
Also gonna cam swap when I do the blower swap do you think the 651 crane will work for my setup? |
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