BBC 509cid tunnel ram efi build.
#31
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From: Finland
Fwiw I know someone that used that ron sporl grind in a modded 502 mag, had a chopped down , extrude honed intake, bored tb, dart heads. He advised customer to advance it some, guy randomly advanced it i think 4 degrees without bothering to degree it, broke 620 hp on my dyno at about 5500/ 5600 using J607, dry dyno headers with mufflers and no accessories fwiw, Smitty
#32
FWIW, the guy with the modded 509 w that cam ran 84 in a 280 PQ at LOTO shoot out on day one and 85 on day two (after tearing all the interior out of cockpit and putting it in back of his truck on saturday night)! think that was 3 years ago. We saw 78/79 on local river when checking/touching up the tune before he tried multiple props.
Last edited by articfriends; 04-07-2024 at 12:28 PM.
#33
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From: Finland
Yes, the runner length of 14/15" dictates hp peak on these restricted intake engines, even with intake mods, You can add more and more cam on them and gain nothing, just shifts tq peak to a higher rpm with less overall torque. Modding the runner length and cutting dividers gets them to carry about 200 rpms higher. With your tunnel ram Id expect that cam to easily pull to 6000. IF your dynoing it, would be interesting for you to install a adjustable timing chain and cover that allows you to easily access it and move cam timing around on the dyno and see where your tq vs hp peak goes then make a decision of which ones more important to you.
FWIW, the guy with the modded 509 w that cam ran 84 in a 280 PQ at LOTO shoot out on day one and 85 on day two (after tearing all the interior out of cockpit and putting it in back of his truck on saturday night)! think that was 3 years ago. We saw 78/79 on local river when checking/touching up the tune before he tried multiple props.
FWIW, the guy with the modded 509 w that cam ran 84 in a 280 PQ at LOTO shoot out on day one and 85 on day two (after tearing all the interior out of cockpit and putting it in back of his truck on saturday night)! think that was 3 years ago. We saw 78/79 on local river when checking/touching up the tune before he tried multiple props.
#34
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FWIW, the guy with the modded 509 w that cam ran 84 in a 280 PQ at LOTO shoot out on day one and 85 on day two (after tearing all the interior out of cockpit and putting it in back of his truck on saturday night)! think that was 3 years ago. We saw 78/79 on local river when checking/touching up the tune before he tried multiple props.
#35
There a stepped hull, Ive heard that steve Stepp or something to do with Velocity had input on that 280 PQ hull. I bought a stock one a couple years ago w stock 502 as a quick flip/plus used it to fully develop a 60 lbs injector tune for mefi3 on 100% stock boat, it ran 67/68 gps after bottom was cleaned and was running perfect. Most those 26/27/28 ft boats will barely break 60 gps w stock 502 mags.
Another customer had one and another 509 I dynoed and tuned with promax heads made around 610 on a glory pull and around 580 with marine exhaust and water in exhaust, that boat ran 81/82 at shoout a year or 2 before the other one I mentioned
Another customer had one and another 509 I dynoed and tuned with promax heads made around 610 on a glory pull and around 580 with marine exhaust and water in exhaust, that boat ran 81/82 at shoout a year or 2 before the other one I mentioned
#36
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From: SW Ohio
Jani,
I have an '02. I think it runs really well for the power you give it. Mine has the 496HO with the Whipple stage 2 tune and an M1 ProCharger. Procharger advertises this kit at 615HP. Opinions vary as to what it actually puts out; some suggesting as low as 500. I turn a Bravo1 28P prop, and we run 76-77GPS, maybe 78 on a perfect day, and it will still pull my fat ass out on a slalom. It climbs on plane with little more than 3K RPM, cruises at 30-35MPH at about that same RPM. I think there's more in it (mine) with a more efficient (labbed) prop, but I don't think I can pull a 30P with a happy engine. I've seen videos of them running 85 or so, but I have no idea what power was in it. They run clean and stable at that speed. I think the hull is actually spec'd at 27'6", including swim platform.
Thanks. Brad.
I have an '02. I think it runs really well for the power you give it. Mine has the 496HO with the Whipple stage 2 tune and an M1 ProCharger. Procharger advertises this kit at 615HP. Opinions vary as to what it actually puts out; some suggesting as low as 500. I turn a Bravo1 28P prop, and we run 76-77GPS, maybe 78 on a perfect day, and it will still pull my fat ass out on a slalom. It climbs on plane with little more than 3K RPM, cruises at 30-35MPH at about that same RPM. I think there's more in it (mine) with a more efficient (labbed) prop, but I don't think I can pull a 30P with a happy engine. I've seen videos of them running 85 or so, but I have no idea what power was in it. They run clean and stable at that speed. I think the hull is actually spec'd at 27'6", including swim platform.
Thanks. Brad.
Last edited by Brad Christy; 04-08-2024 at 08:49 AM.
#37
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From: Finland
Jani,
I have an '02. I think it runs really well for the power you give it. Mine has the 496HO with the Whipple stage 2 tune and an M1 ProCharger. Procharger advertises this kit at 615HP. Opinions vary as to what it actually puts out; some suggesting as low as 500. I turn a Bravo1 28P prop, and we run 76-77GPS, maybe 78 on a perfect day, and it will still pull my fat ass out on a slalom. It climbs on plane with little more than 3K RPM, cruises at 30-35MPH at about that same RPM. I think there's more in it (mine) with a more efficient (labbed) prop, but I don't think I can pull a 30P with a happy engine. I've seen videos of them running 85 or so, but I have no idea what power was in it. They run clean and stable at that speed. I think the hull is actually spec'd at 27'6", including swim platform.
Thanks. Brad.
I have an '02. I think it runs really well for the power you give it. Mine has the 496HO with the Whipple stage 2 tune and an M1 ProCharger. Procharger advertises this kit at 615HP. Opinions vary as to what it actually puts out; some suggesting as low as 500. I turn a Bravo1 28P prop, and we run 76-77GPS, maybe 78 on a perfect day, and it will still pull my fat ass out on a slalom. It climbs on plane with little more than 3K RPM, cruises at 30-35MPH at about that same RPM. I think there's more in it (mine) with a more efficient (labbed) prop, but I don't think I can pull a 30P with a happy engine. I've seen videos of them running 85 or so, but I have no idea what power was in it. They run clean and stable at that speed. I think the hull is actually spec'd at 27'6", including swim platform.
Thanks. Brad.
Last edited by JaniH; 04-08-2024 at 12:17 PM.
#38
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From: Finland
Damn it was hard to decide put the domes are now machined to 6cc, wich gives me 9.8 to 1 comp for N/A power. Now trying find the perfrect lobes, and imo howards has the most interesting cams with less duration split. Someone said that picking a cam more complex than picking a wife.


#39
Jani,
I have an '02. I think it runs really well for the power you give it. Mine has the 496HO with the Whipple stage 2 tune and an M1 ProCharger. Procharger advertises this kit at 615HP. Opinions vary as to what it actually puts out; some suggesting as low as 500. I turn a Bravo1 28P prop, and we run 76-77GPS, maybe 78 on a perfect day, and it will still pull my fat ass out on a slalom. It climbs on plane with little more than 3K RPM, cruises at 30-35MPH at about that same RPM. I think there's more in it (mine) with a more efficient (labbed) prop, but I don't think I can pull a 30P with a happy engine. I've seen videos of them running 85 or so, but I have no idea what power was in it. They run clean and stable at that speed. I think the hull is actually spec'd at 27'6", including swim platform.
Thanks. Brad.
I have an '02. I think it runs really well for the power you give it. Mine has the 496HO with the Whipple stage 2 tune and an M1 ProCharger. Procharger advertises this kit at 615HP. Opinions vary as to what it actually puts out; some suggesting as low as 500. I turn a Bravo1 28P prop, and we run 76-77GPS, maybe 78 on a perfect day, and it will still pull my fat ass out on a slalom. It climbs on plane with little more than 3K RPM, cruises at 30-35MPH at about that same RPM. I think there's more in it (mine) with a more efficient (labbed) prop, but I don't think I can pull a 30P with a happy engine. I've seen videos of them running 85 or so, but I have no idea what power was in it. They run clean and stable at that speed. I think the hull is actually spec'd at 27'6", including swim platform.
Thanks. Brad.
#40
Confirmed the dome volume from JE tech support, for the 0.079" dome height what is left after machine work. JE confirmed that it is approx 7.48cc instead of 6cc that was my own calculation. This gets me 10 to 1 compression. I repeat approximately 7.48cc 🤣🤣🤣. I got the answear in 1 hour, gotta love Je tech support 👌



