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Big block to small block need info?!?!?!

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oddjob

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I have recently picked up a rinker 236 for a little bit of nothing bc the BIG block was locked up and they sold the bravo 1 but it came with a new SMALL block and a alpha outdrive so my question is will the sbc be enough for this boat bc the bbc is 320 hp and the sbc is 230 hp any info would be greatly appreciated thanks
 
If by SBC you mean 5.0L... yes per KGHOST too small! Iv'e been there done that more than once, going the other way, i.e. 4.6 to 5.7L . My fuel consumption and % WOT RPMs needed to plane improved dramatically when I went to a 5.7 on my deepV 23 ft (24degree deadrise, 4000# dry cuddy cabin).
 
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First... what are your expectations from this 23 footer?

If you expect high speeds and performance, and have previously been satisfied with BBC power, I'll agree.... you may be disappointed in a SBC.

FYI: a well built 6.3L (aka 383) SBC with a good quench dimension will produce close to the same torque. Not quite... but close.
The key is in the "quench", IMO.

The 5.7L SBC will not perform nearly as well as the 6.3L SBC... but again, the key is the quench.



The A drive's limit is approx 300 hp and 26 foot in hull size... according to Merc and other sources.

The A drive is a Dog Clutch drive.... the B drives are Cone Clutch.


.
 
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RicardoMarine said:
First... what are your expectations from this 23 footer?

If you expect high speeds and performance, and have previously been satisfied with BBC power, I'll agree.... you may be disappointed in a SBC.

FYI: a well built 6.3L (aka 383) SBC with a good quench dimension will produce close to the same torque. Not quite... but close.
The key is in the "quench", IMO.

The 5.7L SBC will not perform nearly as well as the 6.3L SBC... but again, the key is the quench.



The A drive's limit is approx 300 hp and 26 foot in hull size... according to Merc and other sources.

The A drive is a Dog Clutch drive.... the B drives are Cone Clutch.


.
Click to expand...

I just want it to go up and down the river and sound good i didnt know if it would have problems planing out i could care less of it running 60+ like it would with the 454 and the small block is a 305
 
In short it will power the boat,

It is way under powered to push a boat that size at any high rate of speed. Not 60 but more like 30 + will be difficult!!

So if you want to use it knock yourself out.

But remember it is the wrong power to wieght ratio and you asked and we answered..........

And yes you WILL have a problem planing out..........without a doubt!!
 
RicardoMarine said:
First... what are your expectations from this 23 footer?

If you expect high speeds and performance, and have previously been satisfied with BBC power, I'll agree.... you may be disappointed in a SBC.

FYI: a well built 6.3L (aka 383) SBC with a good quench dimension will produce close to the same torque. Not quite... but close.
The key is in the "quench", IMO.

The 5.7L SBC will not perform nearly as well as the 6.3L SBC... but again, the key is the quench.



The A drive's limit is approx 300 hp and 26 foot in hull size... according to Merc and other sources.

The A drive is a Dog Clutch drive.... the B drives are Cone Clutch.


.
Click to expand...

FYI

The 383 stroker falls extremely short replacing a 7.4......

It is a poor replacement.
 
oddjob said:
I have recently picked up a rinker 236 for a little bit of nothing bc the BIG block was locked up and they sold the bravo 1 but it came with a new SMALL block and a alpha outdrive so my question is will the sbc be enough for this boat bc the bbc is 320 hp and the sbc is 230 hp any info would be greatly appreciated thanks
Click to expand...


There is no replacement for displacement.


If you do this you will also need to change the transom assembly.
 
Docksidemarineservices said:
FYI

1.... The 383 stroker falls extremely short replacing a 7.4......

2..... It is a poor replacement.
Click to expand...

1.... The 6.3L (383) SBC, as built by most shops, would fall short. No disagreement there.
The Full Dished piston is the downfall!

2.... Keep in mind the weight differential between the BB and SB.


I will agree..... there's no replacement for displacement! :D



.
 
Ditto KGHOST's post!

A 230 HP 302 (5.0L) engine is a gutless wonder, more suited to a 19ft boat. Its not HP that moves a boat, its CID displacement! Small displacement engines get their HP rating by running the engine faster and specifying it at higher RPMs. The 30 mph quoted in a previous post for your proposed engine would be for wide open throttle... not a place you want to run it for more than a few seconds. The smallest engine I would recommend in your boat would be a 5.7 (350)... If you got the FI version you'd likely have a 30 mph cruise and a 40 mph WOT. I've got the 2BBL carbed version (intentionally) and cruise @ 27 MPH (80% WOT) and have a 38 mph @wide open.... (Deep V's eat power).... at 2400 RPM, my boat has a nice sedate, comfortable cruise at about 18 MPH... and with the exhaust out thru the transom with a pair of 3" Centek mufflers, sounds nice.
 
oddjob said:
I just want it to go up and down the river and sound good i didnt know if it would have problems planing out i could care less of it running 60+ like it would with the 454 and the small block is a 305
Click to expand...

It probably went mid 40's with the 454
 
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