406 small block install

[ironeel]

Im thinking of installing a 406 small block in my scarab. Anyone out there familiar with this motor and if it makes a good marine application? Any info would be helpful.
Thanks

 

[Bt Doctur]

Re: 406 small block install

Never heard of a 406
might be helpful to supply some more info, mfg.

 

[Mkos1980]

Re: 406 small block install

400 SBC bored 30 over = 406

Its a good engine, just build it like any other marine build and you should be fine.

 

[skargo]

Re: 406 small block install

I have a Pontiac 406 for my 1967 Lemans, it's a punched out 400 (.30 over)

 

[Bondo]

Re: 406 small block install

I have a Pontiac 406 for my 1967 Lemans, it's a punched out 400 (.30 over)

Ayuh,... But a Pontiac motor Ain't goin' in a Boat...

The 400 Chevy wll work Just Fine....

 

[skargo]

Re: 406 small block install

Ayuh,... But a Pontiac motor Ain't goin' in a Boat...

The 400 Chevy wll work Just Fine....

Never said it was, just relating my 406 to the subject matter at hand.
I do know of 2 pontac powered boats BTW

 

[Mkos1980]

Re: 406 small block install

If you can find Dennis Moores SBC Marine Performance book, he writes very highly of the 400 motor and the steps it take to build one for a marine enviroment.

 

[Bondo]

Re: 406 small block install

Ayuh,... The 400 was a Truck motor.... The Problems arose when it was adapted to Hot Rodding...

 

[Bt Doctur]

Re: 406 small block install

What ever happened to those 327`s with 375Hp

 

[Mkos1980]

Re: 406 small block install

There out there but you need to turn some serious RPM's to get there. Sorta like the 302 Chevy. I think some of those were turning 7500+ RPM's to achieve those numbers.

 

[skargo]

Re: 406 small block install

What ever happened to those 327`s with 375Hp

I have 2, one in car, and one on a stand.

 

[bigblocksarefun]

Re: 406 small block install

I would NOT put a 400 (406) into a marine application. Those engines had a lot of problems (and is why GM stopped making them) and I don't believe it would hold up very well in marine duty. The biggest issue is they had weak main bearing webbing and with 2-bolt mains had a tendancy to come apart when pushed hard for extended periods.

The fact you simply never seen an OEM use it in a boat should tell you something... As in GM never offered it for marine use. I don't know if you can even find marine gaskets (head) for it.

In addition to the above, 400 SBC's are a very thinwall casting (if you are using an old production casting). They don't hold up to overheats well at all. Now a 383 stroker (350 block with 400 crank) makes for a good torquey engine, big block power in a small block package.

 

[MikDee]

Re: 406 small block install

On a side note here, I had a 72' Chevy Caprice 2dr Sport Coupe one time with a 402/396 4bbl it was sweet. I happened to find out that if you ordered the V8 eng with a 2bbl, you got a 400 small block and if you ordered the V8 4bbl version you got the big block, I was pretty happy

 

[wca_tim]

Re: 406 small block install

I've had a couple of 400 small blocks, one that was significantly modified with no real problems...

I love the 383 I had built for my current boat.

I think that either would be great as would one of the longer stroke 4 inch bore set-ups like a 408 (0.25 more stroke than 383.. as in 4" stroke s,mall block...) serious amounts of both torque and horsepower in the right set-ups.

 

[skargo]

Re: 406 small block install

On a side note here, I had a 72' Chevy Caprice 2dr Sport Coupe one time with a 402/396 4bbl it was sweet. I happened to find out that if you ordered the V8 eng with a 2bbl, you got a 400 small block and if you ordered the V8 4bbl version you got the big block, I was pretty happy

hehehe, I had a 72' Caprice myself, but with the 400. That car was a great highway cruiser! I bought mine used though, I was only 5 in '72.

 

[bigblocksarefun]

Re: 406 small block install

My uncle came into possession of a 70 El Camino that someone had dropped a healthy 400 SBC into (probably pushing about 360 hp or so). Fast car, but scary to try and stop with the original manual drum brakes!

 

[gotchacovered]

Re: 406 small block install

I've got a 406 in my dirt late model. 4.155 bore in a 184A block. 3.750 stroke. 18 degree bowtie heads. puts out 718 hp and 600 lbs of torque. great engine. however in my boat I have a 120 mercruiser, runs so quiet I can hardly tell its running.

 

[Don S]

Re: 406 small block install

Wait till some of you "Car Guys" find out that a boat engine operates completely different from a car (aka hot rod, street rod, etc.)
What works great in a 70 El Camino (as an example) may be pure junk in a boat within a few trips.

 

[ironeel]

Re: 406 small block install

Thanks for the input guys, the engine is a 1972 chevy 400 that's bored .030 over. The block is a 2 bolt main high nickel block. My engine builder is putting speed pro pistons (10.1 compression), scat H-beam rods and a forged crank. He said marine gaskets wouldn't be a problem as well as fitting vortec heads to the block. We are going to run a mid range comp marine cam and I was told this engine should have similar characteristics to a 383 but more torque at lower RPM. The motor is going into a 22 scarab.
I was looking for a motor that could get the boat out of the hole and cruise 50 mph all day.
This is what was recommended to me??
Maybe I should have done a 383?

 

[Mkos1980]

Re: 406 small block install

My 350 will cruise all day at 50MPH.