Small Block 400 swap

reswest101

Recruit
Joined
Apr 9, 2009
Messages
3
Hi there

I own a 1998 22 foot cuddy with a Vortec 305 and an Alpha Leg. About 4 years ago I froze the motor and cracked the block. It still starts up fine and has no water in the oil but leaks alot into the boat. Originally we had considered trying to weld or somehow patch the block from the outside but was told that it would not likely work.

I have since been considering purchasing a long block 350 to replace the 305 on the understanding that most parts would swap over quite easily and I would only need to purchase a four barrel manifold, a new carb to replace the two barrel on my engine, and perhaps a few other minor items.

Recently I was able to locate a newly rebuilt 400 small block out of a mid 70's chev pickup. What I would like to know is how much extra work/expense will I potentially be getting myself into by not going with a newer Vortec upgrade, if it is even possible? Will most of the parts such as the manifolds, ignition, starter, etc still bolt on as I have been told? Will the Alpha leg withstand the extra power of the 400?

Any input or advice will be greatly appreciated.

Thanks Gary
 

pole position

Petty Officer 2nd Class
Joined
Dec 14, 2008
Messages
156
Re: Small Block 400 swap

For one thing those 400 small blocks are balanced differently. You need to use the flywheel and harmonic balancer for the 400. They are different from any other sb. I made that mistake before. The oil pan end seals are not one piece like the 1985 and up. You would need a new pan. Starter is different. I would think you'd be better off with a new 350. You can get a nice 300-325 horse 350 for not much more than a stock one. Just my 02 cents.
 

picklenjim

Chief Petty Officer
Joined
Mar 11, 2009
Messages
528
Re: Small Block 400 swap

I once patched up an exhaust manifold on a 327 in my old Chris Craft with JB Weld.It worked fine,never leaked again.I guess it probably depends on how big of a crack you have.
 

Howard Sterndrive

Rear Admiral
Joined
Nov 5, 2008
Messages
4,603
Re: Small Block 400 swap

400 is not really popular for RWC marine apps. because of the steam holes in the heads.
350 the best bet
I'm not a fan of rebuilt engines when a crate is available affordably.And a crate 350 is readily available.
 
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