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Tell me about the 396 BBC

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Found a mid 70's 20' V Drive boat that caught my interest. It has a 396 BBC 4 bolt main and a velvet drive. I know nothing about them as I asked if 396 was a typo for 496. How is the 396 overall and how does it perform in a marine V drive application? Speed and big power isn't too important to me. Just looking for something that is reliable, enough power to plane easy, and top speed around the 55 mph range. Parts easy to find and repair? What are the thoughts on velvet drives?
 

mash on it

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What's to know?
Same stroke as a 427, at 3.76".
Smaller bore tho.
Same physical size as a 427, 454, 496, 502, etc.
Early 70's Chevy 396's had a 325, 350 and 375 hp versions.
Guessing on how much hp a 396 is in a 40+ year old boat is nearly impossible.

A stockish 325 hp should be 50-ish mph. A lot depends on rigging, gearing and prop size, bottom condition, plus weight of the boat.

396's have typical big block problems/issues. Nothing that enough money can't solve.

Dan'l
 

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What's to know?
Same stroke as a 427, at 3.76".
Smaller bore tho.
Same physical size as a 427, 454, 496, 502, etc.
Early 70's Chevy 396's had a 325, 350 and 375 hp versions.
Guessing on how much hp a 396 is in a 40+ year old boat is nearly impossible.

A stockish 325 hp should be 50-ish mph. A lot depends on rigging, gearing and prop size, bottom condition, plus weight of the boat.

396's have typical big block problems/issues. Nothing that enough money can't solve.

Dan'l
Thanks for the info. I've seen many for sale ads but don't recall ever seeing a boat with a 396 for power. It seems rare. I just don't know anything about them. If they are a good engine for marine use or should just stay on the road? Temperamental on the water like Fords or pretty good like 454s and 502s? I would have no interest in building power out of it. I get it's a mechanical device... but want something that is add gas and go. Are there USCG approved parts for a 396?
 

rivermobster

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Thanks for the info. I've seen many for sale ads but don't recall ever seeing a boat with a 396 for power. It seems rare. I just don't know anything about them. If they are a good engine for marine use or should just stay on the road? Temperamental on the water like Fords or pretty good like 454s and 502s? I would have no interest in building power out of it. I get it's a mechanical device... but want something that is add gas and go. Are there USCG approved parts for a 396?
It's a BBC. Same as all rest of em, just a different displacement. https://en.wikipedia.org/wiki/Chevrolet_big-block_engine

Any engine, ford, dodge or chebby, is only as good as the guy that built it, and more importantly, tuned it. You'd have to talk to the guy that built it to see if it was built to marine specs, or not. It's unlikely to be stock after all these years, since it's probably around 50 years old.

If it runs good, run it! 👍
 

mash on it

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Thanks for the info. I've seen many for sale ads but don't recall ever seeing a boat with a 396 for power. It seems rare. I just don't know anything about them. If they are a good engine for marine use or should just stay on the road? Temperamental on the water like Fords or pretty good like 454s and 502s? I would have no interest in building power out of it. I get it's a mechanical device... but want something that is add gas and go. Are there USCG approved parts for a 396?
USCG approved parts?
Alternator, yes
Distributor, yes
Starter, yes
Carburetor, yes
Fuel pump, yes
Flame arrestors, yes.
I think that's about it. All of these would fit a 396 or a Mk IV 454.

Likely half of this wasn't USGC approved when it was new.

I'd check block casting numbers to determine what it started out as.
Same with head #'s.

Fwiw- a neighbor down the road bought a '74 ish Nova. It was advertised as a 383. Ended up a 283 by the casting numbers. It ran ok, but not like a big cammed 383 should run.

Dan'l
 

gottaminute?

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USCG approved parts?
Alternator, yes
Distributor, yes
Starter, yes
Carburetor, yes
Fuel pump, yes
Flame arrestors, yes.
I think that's about it. All of these would fit a 396 or a Mk IV 454.

Likely half of this wasn't USGC approved when it was new.

I'd check block casting numbers to determine what it started out as.
Same with head #'s.

Fwiw- a neighbor down the road bought a '74 ish Nova. It was advertised as a 383. Ended up a 283 by the casting numbers. It ran ok, but not like a big cammed 383 should run.

Dan'l
the 396 will run an early vdrive all day long for summer after summer. late 60s early 70s their were a lot of them racing up and down the river/lake. They came in 2 and 4 bolt main versions, cast and forged cranks. the original rectangular port heads were developed for the 396. it was factory bored to 402ci for the 70 chevelles and pickups. then the bore increased to 4.25 and the 427 was born. Later the stroke was changed from 3.76 to 4.0 an we had 454s. A bigger bore made the 502.

if the boat is the one you want, buy it. you can always build more horsepower. with the exception of just a few parts, everything on the 396 will transfer to a bigger big block.
as far as carbs, fuel pumps, starters, flame arrestor etc, such approved parts are not required on an open hatch boat. state laws may be different . Early v-drives used 390/406/427 fords, 394 oldsmobiles, 389 and 400 pontiacs, 401 nail head buicks.... embrace the nostalgia and RUN IT.
 

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I should have mentioned the boat is a Howard day cruiser. Dog house engine hatch.
 

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the 396 will run an early vdrive all day long for summer after summer. late 60s early 70s their were a lot of them racing up and down the river/lake. They came in 2 and 4 bolt main versions, cast and forged cranks. the original rectangular port heads were developed for the 396. it was factory bored to 402ci for the 70 chevelles and pickups. then the bore increased to 4.25 and the 427 was born. Later the stroke was changed from 3.76 to 4.0 an we had 454s. A bigger bore made the 502.

if the boat is the one you want, buy it. you can always build more horsepower. with the exception of just a few parts, everything on the 396 will transfer to a bigger big block.
as far as carbs, fuel pumps, starters, flame arrestor etc, such approved parts are not required on an open hatch boat. state laws may be different . Early v-drives used 390/406/427 fords, 394 oldsmobiles, 389 and 400 pontiacs, 401 nail head buicks.... embrace the nostalgia and RUN IT.
Thanks for the information. Sounds like the 396 is the predecessor to the 454. It's just a smaller big block making less power due to size but has that GM reputation.
 

gottaminute?

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Thanks for the information. Sounds like the 396 is the predecessor to the 454. It's just a smaller big block making less power due to size but has that GM reputation.
correct, BUT, The doghouse engine cover does change the rules a bit. As kids, we had a family we camped with that had a 24ft Taylor with a 354 hemi that came out of their retired 17 footer. no speed demon . pulled the kids and the "full size" dad on a water ski for quite a few years before it was upgraded to a 454 chevrolet.
 

74 spectra20 v-drive

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dimensionally the 396 is the exact engine as a 454, the "meat on the bones" so to say is different. In a typical 396 block, boring the cylinders to a larger diameter could cause some issues with heat down the road. I am actually doing some homework on one right now for a friend. My current game plan is to use the 396 crank in a 454 block and make a 427. It's a good motor not going to push that howard much past 50 to 55 in my opinion, but can be a solid cruiser.
 
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obnoxious001

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dimensionally the 396 is the exact engine as a 454, the "meat on the bones" so to say is different. In a typical 396 block, boring the the cylinders to a larger diameter could cause some issues with heat down the road. I am actually doing some homework right now on one right now for a friend. My current game plan is to use the 396 crank in a 454 block and make a 427. It's a good motor not going to push that howard much past 50 to 55 in my opinion, but can be a solid cruiser.
If you are going to the trouble of getting a 454 block, get the crank as well. More cubic inches just means a bit more power and torque given the same basic parameters. Or for that matter, buy a new cast 4.25" stroke crank for more cubic inches. The cast ones are super reasonable and good if you aren't doing something with big power. 1 horsepower per cubic inch is very easy now days with a good match of cam and heads.
 
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74 spectra20 v-drive

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Hey Barry, we are just screwing around with a worn out 396 in a friends Sanger. She is in her early 60's and just cruises the boat on Kings river during the summer, I re rigged the boat for her and she loves it but its generating so much crank case pressure that it pushing oil out everylace, has terrible compression as well. Was supposed to have been a fresh rebuild but i don't think so. She says the boat is plenty fast for her and I have always just loved saying 427... :) Thanks for the input and i may just heed your advice as well.
 
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