SoCal Jet Boats
Tech Talk => Projects => Topic started by: steigst on June 04, 2023, 08:06:23 PM
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Hey guys, it?s been a few years but I?ve gotten back in the jetboat game and have a few questions for the salty veterans. I picked up an 18? 1973 Apollo Starfire with a 455 olds and a dominator pump. It?s in my shop getting transom wood and stringers but I had the chance to take it out once before I started to tear into it. I couldn?t get my GPS app to work but my ass-o-meter says the BBO was pushing me between 55-60 mph at 4500rpm and AA impeller. It?s a pretty neat boat that is all original except for the dominator which was installed in the 90?s (12s) and appears to have had very little use. The 455 is the packajet 445-2a model with 330hp@4700rpm and 10.25:1 comp Ga heads w/ quadrajet. I have the engine out and plan to freshen it up. I thought about putting in a camshaft but it seems like the motor and pump are already matched up well.
TL:DR my main question is this:
If you had the pump and intake of a 330hp/55mph runabout lake boat sitting on the shop floor what would you do to it? Best bang for buck? I read this thread from the archive: https://www.socaljetboats.com/jet-pumps/best-performance-jet-mod/
My first thought is to start with a place diverter and go from there but I?m curious to see what other people?s opinions are as far what would benefit my setup the most i.e. shoe, ride plate, loader, etc.
TYIA
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Nice start to a fun ride!
What are the intentions for the boat? just looking for a little more speed?
i would do upgrades in this order.....
1.) Place diverter - Definitely
looking for a bit more money to spend?
2.) nice quality loader
still got a few hundred in your pocket?
3.) HPH nozzle.
out of curiosity, what intake is on the olds? What oil pan? Also, i doubt the engine still has 10.25 compression if it has ever been apart and had head gaskets changed.
Good luck, keep us updated
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This boat will be a runaround on the river. The place diverter is a for sure, if nothing else for convenience of having trim. Adding top speed is always a bonus. Would a loader require me to change impellers? I don?t want to overload the pump if my wot rpm?s are already where they are at. What is the benefit of the hog nozzle? Why not a full droop and ride plate combo?
The previous owner said the motor was untouched and he bought it in the early seventies. I don?t have the casting numbers off the intake, unfortunately. I have no reason to believe any parts are not original. I also have all the paperwork from all the work orders done to the boat since it was new from the boat shop.
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Forgot to add that oil pan is only 5 quarts.