455 to small block chevy

[old rigger]

gochappy,
no parts, but you'll be just as happy running a small block chevy as you are with the olds, if your boat is a 18 footer, give or take a few inches. Any bigger, like a mini cruiser and you'll want the grunt of a big block.
We sold a bunch of 18 bubbledecks at Advantage with the sbc/berk combo (e pumps no less) and they'd run low 60s all day long with the stock engine. Plus, when you go to rebuild the sbc, it'll cost you a 1/3 of what the olds will.
I like the olds, don't get me wrong, but for an everyday fun boat that you only want to ski and dick around in, smart choice with the chebbie.
Jethro over on the banderlog board runs a sbc in his boat, or one of his many, and I think he runs about 63-63 mph.

[miketsouth]

Fix the Olds...........A lot less work and expense, and a SBC won't put out the torque in a jet RPM range..............MP
so they told me
i am tickled pink with my small block chevy plenty good enough for 60 mph or so in my 18 ft flatbottom. couldn't ask for a better torque curve in the useable range. plus, it's WAY cheaper to maintain and repair.
so i found.
my wife likes it too (http://mywebpages.comcast.net/katiej...blastanna1.wmv)
Fact is that it will take a very light tunnel about 70. It is cheep (mine was, POS ebay <9:1 engine). It will take WOT all day. It needs WOT all day if you riding with others with big blocks.
I used a b impeller and am going to try a c this year, as well as a better engine. Somehow i dont think the c is going to do as well as the b even though i will be using more gas and producing more wear and horsepower. 4800 w/30lbs intake pressure@70mph.

[mrossum]

Is it turning a jet, or a prop????????
it is turning a decent shape panther jet

[mrossum]

Fact is that it will take a very light tunnel about 70. It is cheep (mine was, POS ebay <9:1 engine). It will take WOT all day. It needs WOT all day if you riding with others with big blocks.
again, i do not want to start a flame war, but...
i am afraid i just don't understand. if my boat goes, say, 60 mhp turning pump at 5500, what difference does the engine type make? 5500 is 5500 regardless. coming from a dirt track racing background, i have to believe that a stock small block can run 5500 all day without really stressing the motor. i do not believe a big block in stockish trim can do that. i have stock 83 chev truck 350, 8.2 to 1 short block with mild cam, edelbrock rpm air gap intake and edelbrock 600 carb. can run 5500 all day, and maybe even get to 6000 on occasion. total of $1000 in the engine, including cost of engine to begin with.
if i am way off line, please splain it to me so i understand better.

[Moneypitt]

First, a jet is not a dirt track car, or a truck, or a prop boat. 2nd, a jet requires a constant amount of torque to maintain a given RPM. Very few SBC will deliver that torque in the lower RPM ranges, the same ranges that are required to pull skiers, and especially hydrodynamic challenged tubes and other water toys your kids may want to ride on. Imagine trying to pull 2 kids on a tube at, say 25 MPH. The boat will not be planed, and will be mushing through the water at 2800-3K. What kind of torque does a SBC put out at those RPMs? You mention 5500 like a jet will allow you to spin it that hard, most won't, a stock pump will limit you to about 4500-5K in an empty boat pulling nothing. A bigger inch motor, like the 455 will make the torque in a much lower range, allowing the use of the above mentioned water toys at a safe speed for the kids. There are pumps that are worked and dialed in to allow the higher RPMs with a whole bunch of HP and torque, and there are boats that run just fine with SBCs. But ask yourself, if you were building jetboats back in the heyday of jetboats, and could get the same results and performance from a SBC WHY would you spend the extra money for the Hardin Marine Oldsmobile 455s? When you could buy SBCs for about 1/2 the cost? The is no substitute for cu in. In a prop boat, you can gear and prop the boat into the desired RPM range of the SBC. A jet drive is direct, no gears, no "crutches", between the motor and the pump. Take 2 identical boats, with 2 identical pumps, put a SBC in one and a 455 in the other, and I guarentee you, you will see the reasoning behind my statements.......MP

[Beer-30]

YOu could actually go BIGGER with a small block chevy!:
http://www.ultrastreet.net/ultrastre..._675_ultra.jpg

[maxwedge]

So when I read all the "Jet pumps require large amounts of tourqe" threads, I always wonder why we aren't all running hopped up turbo diesels and gearboxes. Sure they are a little large and weighty but 1000+ ftlbs at 2500rpm seems nice, doesn't it? I've decided I'm swapping in a nice Cummins when my Olds dies

[Moneypitt]

It all comes down to "bang for the buck". The power plants just shown would work in just about anything. But the cost is off the scale, compared to rebuilding the existing Olds, or replacing with a reasonable priced SBC. I really don't care what he decides to do, but after doing some engine changes, one brand to another, I am just relating the reality of all the work that could be avoided, and the expense of the changeover spent on bettering the Olds. From what I've read, he doesn't have a kick ass SBC sitting around, and to go through the trouble of this change over for a run of the mill SBC, I feel he will be disapointed. I will also add, if the olds is all there and just in need of TLC, he won't have any problem selling it to another jetboater that likes the brute feeling of the torquey BB Olds...........BTW, anyone priced SBC exhaust systems lately?...................MP

[canuck1]

First, a jet is not a dirt track car, or a truck, or a prop boat. 2nd, a jet requires a constant amount of torque to maintain a given RPM. Very few SBC will deliver that torque in the lower RPM ranges, the same ranges that are required to pull skiers, and especially hydrodynamic challenged tubes and other water toys your kids may want to ride on. Imagine trying to pull 2 kids on a tube at, say 25 MPH. The boat will not be planed, and will be mushing through the water at 2800-3K. What kind of torque does a SBC put out at those RPMs? You mention 5500 like a jet will allow you to spin it that hard, most won't, a stock pump will limit you to about 4500-5K in an empty boat pulling nothing. A bigger inch motor, like the 455 will make the torque in a much lower range, allowing the use of the above mentioned water toys at a safe speed for the kids. There are pumps that are worked and dialed in to allow the higher RPMs with a whole bunch of HP and torque, and there are boats that run just fine with SBCs. But ask yourself, if you were building jetboats back in the heyday of jetboats, and could get the same results and performance from a SBC WHY would you spend the extra money for the Hardin Marine Oldsmobile 455s? When you could buy SBCs for about 1/2 the cost? The is no substitute for cu in. In a prop boat, you can gear and prop the boat into the desired RPM range of the SBC. A jet drive is direct, no gears, no "crutches", between the motor and the pump. Take 2 identical boats, with 2 identical pumps, put a SBC in one and a 455 in the other, and I guarentee you, you will see the reasoning behind my statements.......MP
Well sorry Money Pit but you are wrong. A stock ZZ4 will provide more than the average 455 will. I can pull tubes all day long at 22 - 2800 with out a diverter on plane or run around at 5000 and stomp on your 455 instead....Your choice.
Maybe taking a couple of hundred pounds off the ass end will help some of the slugs from the 70's. Big blocks are for tow vehicles

[Moneypitt]

So he is installing a stock ZZ4? What does one of those sell for? And just for laughs I'll run you with MY 455 anytime...............Mp