120/140 motor question

[p3ghost]

Hey All,

I posted this in Starcraft section and they recommended that I come here to get the true expert opinions.

Here's my scoop. I got a "free" '78 Starcraft with 140 hp I/O with a cracked block. I've managed to score two 120 hp engines, but they are in pieces. One of them has a cracked block, but the other is golden.

What I really want to do is use the head, exhaust manifold, and carb from the original 140 hp engine and mount it up to the 120 hp block (casting number 3915991).

Can I do it?

Thanks,

Chris

 

[fishrdan]

Re: 120/140 motor question

Well, you could, but if you did, you'd be wanting that extra 20HP a year down the road and wondering why you didn't get a 140. The 120 to 140 swap is common, not so much with a 140 to 120 swap.

How cracked is the block, people have been known to JBweld an external crack and have it hold. If it's an internal crack, it's hosed. (It's hosed either way, but you might be able to run a JBwelded block)

 

[p3ghost]

Re: 120/140 motor question

Crack was internal and a pretty bad one at that. Whoever had it before me left water in it for several winters without use. I tried looking for a 140 on craigslist, but no luck. The 120 block was the only affordable option. I'm not all that concerned about the reduced HP, I'm just hoping the head, exhaust manifold, and carb are all interchangeable between the 120 & 140 blocks.

 

[wardfamid]

Re: 120/140 motor question

DONT JB WELD THE BLOCK! You will be sorry you did. Just use the 120 hp, 20 hp is not much difference at all.

 

[Fordiesel69]

Re: 120/140 motor question

This is only my personal opinion. Iwould run TWO bilge pumps. One low that is auto/manual, and then an auto up a tad higher for redundancy. If you JB weld the block and it leaks a bit the pump will be able to keep up. After all it is free.

I don;t find this a saftey issue as there is plently of pump power. If it ever cracked more and started leaking too much, turning off the engine until the bilge empties out would suffice.

Or search for a 140HP drop in engine. You can find them, but they are harder to find than a 120.

 

[fastryker]

Re: 120/140 motor question

I saw a couple of 140 engines for sale on ebay yesterday, one was at 1000 bucks on bid, all together and ready to go. Check it out man! If you want a 140.

 

[starcrafter65]

Re: 120/140 motor question

DONT JB WELD THE BLOCK! You will be sorry you did. Just use the 120 hp, 20 hp is not much difference at all.

I JB welded my block 3 years ago - works great - external crack under exhaust manifold. Details on my resto thread - I beleive making sure it is clean is the key. Remember there is no pressure on the exhaust side.

What outdrive do you have?

 

[p3ghost]

Re: 120/140 motor question

I'm not really sure what outdrive it is....I don't see any numbers or anything on it. I know that with the coupler I have, I was able to mate everything together. Main reason I want to use the head, carb, and exhaust manifold from the 140 block is because of the way the linkage connects. It would be so much easier to connect everything if I can use those 3 parts.

Thanks!