1968 Rayson-Craft 18' Jet Resto Project

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SyTy Speed Shop

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Ok, as some of you know i have been looking for a jet boat project for about a year and a half, found what i thought was a cool 72 Sea-Ray Jet with an Olds 455 but it turned out to be way to rotten so i scrapped it and parted it out.  Kept looking and i knew i wanted something cool and unique and not like every other boat at the lake(or river) and to me once you get into the mid-late 70's they all start to look the same, and while google searching i came across this 68 18' Rayson-Craft, and unlike most of there boats that were v-drive this one was a jet.  Now from more research i found that RC only made around 250 boats a year, no exact numbers on how many were jets vs v-drives, but id say its not many.  I also found this advertisement that shows a boat that looks almost identical to mine, except for the windshield, which i found was an optional accessory, im not sure if this one had it or now, and i am missing the original engine cover, but since its probably next to impossible to find one im going to build it as an open engine compartment.  The boat was originally red and gold, but im thinking about doing a plum crazy purple and white color scheme and naming the boat "Plum Crazy" LOL but just not sure yet.

Anyways here is a link to pics, i have all of these posted in my other thread, so i wont re-post them here.  Will post pics from this point on in this thread.

http://s1146.photobucket.com/user/HotRodV6/library/1968%20Rayson-Craft%2018%20Jet%20Boat

 
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SyTy Speed Shop

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I've got a gen 6 454 Block and going to get a 3.766 one piece seal Crank and build a 427, I want to build the engine for around 650HP at the Crank and I have an edelbrock pro-flo xt EFI intake and am looking at some AFR 265 magnum heads.  I have a build sheet for a similar Carb engine that was a 468 and made 620, and that was with low CR, so I think with more CR and a better cam profile and the EFI I can hit my number or get dam close!
 
Patchman

Patchman

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That's some serious horsepower for a small cu n/a motor! looking forward to seeing the build! :smile17:
 
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SyTy Speed Shop

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DISTURBED said:
What RPM are you planning on making peak HP at?
Click to expand...

Not planning on spinning it past 6500, and the AFR 265 heads rec a max RPM of 6200, and capable of 700HP on 396-460 cube, its all in the tune and cam profile.

XR300HR from Comp Cams. It a 0.560/0.580 lift split, a 248/254 duration split, and a 110-degree LSA

This cam on a  ~10:1CR 468 with the AFR 265 heads with 112cc chambers AFR 265s, the 468 BBC produced 613 hp and 559 lb-ft of torque. The spring package provided by AFR allowed the hydraulic roller motor to rev cleanly to 6,500 rpm. In terms of average power production from 3,500 rpm to 6,300 rpm, the AFR 265s produced 501 hp and 536 lb-ft of torque, while knocking down 520 lb-ft at 4,000 rpm.

I think with 11:1CR and a cam more optimized the get the valves open faster to maximize the head flow in the mid lift range i can make the 600HP mark pretty easy, and i think i can get close to the 650.

Has anyone gotten a custom cam from Clay Smith before? was thinking about giving them a call and seeing what there thoughts were.
 
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SyTy Speed Shop

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Patchman said:
Post a link to the build if you can. think.gif
Click to expand...

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjKmO2OjY3QAhUriFQKHV3ICnYQFggdMAA&url=http%3A%2F%2Fwww.superchevy.com%2Fhow-to%2Fengines-drivetrain%2Fsucp-1206-oval-port-big-block-chevy-cylinder-heads%2F&usg=AFQjCNH4GV0PB1VRnxXMw2wsUExWcTJUWg&sig2=KC6qRuE06wbOvlXlFeRorw
 
Patchman

Patchman

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One thing you have to keep in mind is you are talking about building a boat motor. RPM range will come at a sacrifice. If you have to spin 6k, you will loose low end cruise. Imagine having a single speed transmission, and all you can change is differential gears! Welcome to the world of the jet pump. To see that kind of rpm in a heavy hull like that you will have to drop down in impeller size. Which means more RPM to get the job done. If I were you, think torque and get it to work in the 45k to 55k range max. For a family boat an A impeller is the most common. I'd build a reliable stump puller! Also to get an impeller that will live at 6K will set you back close to a grand. Just thinking out loud. :smile30:
 
Patchman

Patchman

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And when looking at cams, look into the term reversion! It is not your friend! :smile30:
 
Patchman

Patchman

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http://lightningheaders.com/tech-info(2).htm
This is put out by Lightning headers. Running manifolds reversion is still a concern.
 
D

Disturbed

Active member
Patchman said:
One thing you have to keep in mind is you are talking about building a boat motor. RPM range will come at a sacrifice. If you have to spin 6k, you will loose low end cruise. Imagine having a single speed transmission, and all you can change is differential gears! Welcome to the world of the jet pump. To see that kind of rpm in a heavy hull like that you will have to drop down in impeller size. Which means more RPM to get the job done. If I were you, think torque and get it to work in the 45k to 55k range max. For a family boat an A impeller is the most common. I'd build a reliable stump puller! Also to get an impeller that will live at 6K will set you back close to a grand. Just thinking out loud. :smile30:
Click to expand...

This is exactly where I was going with this.  :smile30:

It's a big, heavy boat.  You'll need a large impeller to get it out of its own way.  My $.02
 
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SyTy Speed Shop

New member
DISTURBED said:
Patchman said:
One thing you have to keep in mind is you are talking about building a boat motor. RPM range will come at a sacrifice. If you have to spin 6k, you will loose low end cruise. Imagine having a single speed transmission, and all you can change is differential gears! Welcome to the world of the jet pump. To see that kind of rpm in a heavy hull like that you will have to drop down in impeller size. Which means more RPM to get the job done. If I were you, think torque and get it to work in the 45k to 55k range max. For a family boat an A impeller is the most common. I'd build a reliable stump puller! Also to get an impeller that will live at 6K will set you back close to a grand. Just thinking out loud. :smile30:
Click to expand...

This is exactly where I was going with this.  :smile30:

It's a big, heavy boat.  You'll need a large impeller to get it out of its own way.  My $.02
Click to expand...

Yeah, i originally came up with the idea of building the 427 for nostalgic reasons, but i was looking at some balanced rotating assemblies and i can get a complete kit to do a 489 with my block for 2K, and then about 3200 for the AFR heads, and with  EFI and the right cam this thing should be a stump puller on torque and still make the power numbers and be a nice cruiser. 

And yes i was reading up on the reversion issue, which was one reason why i was thinking about running the headers dry, and the outlets higher up on the transom than they are now.
 
S

SyTy Speed Shop

New member
Patchman said:
Don't run those logs dry! They won't like that at all.  :smile20:
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No, i dont plan in running the logs at all, the guy just threw them in with the boat.  My intention is to run headers, and since i want to run EFI and need O2 sensors i was gonna just run the headers dry, but have been told thats illegal, so i may have to come up with a different plan.
 
Patchman

Patchman

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If you run them dry, I believe your only option will be over the transom. think.gif
 
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