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mercruiser 350 to 383 stroker, 2mph gain??? what gives.

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mercruiser 350 to 383 stroker, 2mph gain??? what gives.

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Old 05-30-2019 | 07:23 PM
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Originally Posted by guimond47
my ratio is 1.50... i've tried to use the mercury calculator but theres no prop diameter input...
This doesn't add up

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Old 05-30-2019 | 07:29 PM
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Originally Posted by AllDodge
This doesn't add up
sorry,typo. The 19p mirage i was at 5200-5300RPM.- 54-55mph

23P prop was 4400-4600 depending on trim- 52mph
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Old 05-30-2019 | 07:32 PM
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Originally Posted by guimond47
here is the cam part number 295-124188. it is comp cams.
276, 282 at.006"
224,230 at.050"
.503".510" with 1.5 rockers
.537".544" with 1.6 rockers
112°

====================================

So, 425(9:1)-450hp(10:1) capable with RPM Intake and a good tune w/dyno headers.

Difficult, but not impossible for a Quadrajet carb

=======================================

How fast are these boats with a stock 300MPI or 330hp/454 ? hat prop man/model came on boat new with what motor?

For the rest of us that don't know what the OP's model boat style and bottom looks like:.

Last edited by SB; 05-30-2019 at 07:41 PM.
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Old 05-30-2019 | 07:34 PM
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Originally Posted by SB
276282224230.503.510112°,537".544 " lift with 1.6 rockers

====================================d
alright..?
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Old 05-30-2019 | 07:36 PM
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Better numbers

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Old 05-30-2019 | 07:38 PM
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Originally Posted by AllDodge
Better numbers
so the 23p has about 10% more slip. but now if the 23P that is currently 14-1/4" was bigger in diameter like 15.6". slip should go down....
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Old 05-30-2019 | 07:43 PM
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Originally Posted by guimond47
alright..?
Came out weird from a copy/paste. I fixed that post.

Great cam, for marine 383.
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Old 05-30-2019 | 07:48 PM
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Originally Posted by guimond47
so the 23p has about 10% more slip. but now if the 23P that is currently 14-1/4" was bigger in diameter like 15.6". slip should go down....
Maybe, lots a variables in there and slip reduction is good, but sometimes a bit more slip means higher mph. All depends on how well power is transferred from the motor to the prop to hull
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Old 05-30-2019 | 07:50 PM
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Originally Posted by SB
276, 282 at.006"
224,230 at.050"
.503".510" with 1.5 rockers
.537".544" with 1.6 rockers
112°

====================================

So, 425(9:1)-450hp(10:1) capable with RPM Intake and a good tune w/dyno headers.

Difficult, but not impossible for a Quadrajet carb

=======================================

How fast are these boats with a stock 300MPI or 330hp/454 ? hat prop man/model came on boat new with what motor?

For the rest of us that don't know what the OP's model boat style and bottom looks like:.
My compression ratio is around 10.4CR.

JET Performance sells Stage 2 and stage 3 Quadra jets. I am thinking on purchasing one. What do you think. I also was looking at Aftermarket EFI Kits. hard to find one without O2 sensor.... Like FITECH.

STOCK 260 hp merc would say 46-50mph depending on prop.
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Old 05-30-2019 | 07:57 PM
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Whoever is doing the carb. call them and give all specs of engine and boat to order,

Your compression is a little too high for my tastes. Kind of Okay for a LS motor maybe, but this is an old style 23* degree motor. Interesting. 2nd small block here this spring with that high compression.
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