Merc 420 Cyclone engines

Man that appears to be some really decent prices on some of those crate engines.


Has anyone dealt with them before?
 
I've been pondering the idea of two used chevy LS2 engines... the only thing is i'd have to figure out is the wet exhuast. Would be cheap way to atleast get it running? My friends have been putting these things in classic chevy's and import cars and said if you buy it with the ecu its cheap reliable power.

thoughts?

Also, need to move on from the old engine. How much do i list it for?

thanks
 
Brian, I'm a proponent of the cubic inch school. I understand that that the original 420s were 454s, but if you can get a hold of a pair of 502s then you have the room to add cubes with a naturally aspirated engine without doing anything overly special or exotic.I'll admit that I don't know a tremendous amount about the LS2s but it seems to me that whenever you go outside powerplants that use more off the shelf components you're just asking for aggravation especially if budget is a concern.
 
Ok, I would think there would be some "marinizing" involved. Especially to meet USCG.
Hp sounds ok, but torque is what makes ya move. And that's a lot of boat.
Even twin 420 isn't gonna move it much over 60, and that's only if they are built for marine (torque).
Not pissing on your parade, but rather trying to save you a possible mistake - unless well thought out.
 
They would have to be an almost giveaway for me to even consider them. You had big blacks in your boat. Every bracket, mount, wiring, flexplate, etc is going to be for big blocks. Small blocks you'd be starting over, then wanting to change someday.

A apir of completely stock 454 marine engines would put you more ahead than a pair of modified small blocks. I'm assuming you plan on keeping the boat for life because of its importance, so tweaking the big blocks over the years will be a much better overall plan than a conversion now, then a complete re-conversion someday down the road because of the limits of the small block platform.

Now, this is my opinion, and I have been wrong before........
 
If you had a little 26 or 28 with bravos maybe.

By today's standards your boat is underpowered with BB 420's. You are looking in the wrong direction looking at any SB..

If they were free you would be wasting your time and effort to make it work.
 
Lets just pretend they are free and start a list of things you will need.
Exhaust, props and or gear ratio change, brackets, harnesses, starters, thermostat housings. Does it have the same bell housing pattern? Will the drive plate attach to the flywheel? Most every aluminum head engine has fresh water cooling. What type of pulleys and belts are you going to run? Probably need to buy new sea pumps. Oil filter adapters. Wonder if the pans clear the mounts? Thats just what immediately comes to mind. There must be more.

Say you find all that and it doesn't cost anything. You are still going to have to buy the whipples and inter coolers. Then you will have to tweek the fuel system and re program the ECU to make it work. Don't forget the probes for the exhaust gases and the software for the ECU.

After all of that all you can do is hope it runs as well as it used to.
 
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Jim, that was brutal. But, very honest. I'm not an engine guy, but i know enough to know a swap like this is the equivalent of a sex change.
Just find a pair of 454 takeouts and have fun.
 
haha you guys are great... i love to stir things up on here!

Ok, so let start with how much can i post that 454 for for a reasonable price of what it is worth. need to move the thing asap. I have to move again for the 3rd time this year, have not had good luck with housing. Anyways i was going to put all of the parts for the boat back in the engine compartment and just sell the 454 on the stand for $1000? Boat is going to storage yard for the meanwhile.
 
I would think you'd be pretty lucky to get that much for it with everything gone except the long block I'm assuming???? Keeping everything else?
 
They would have to be an almost giveaway for me to even consider them. You had big blacks in your boat. Every bracket, mount, wiring, flexplate, etc is going to be for big blocks. Small blocks you'd be starting over, then wanting to change someday.

A apir of completely stock 454 marine engines would put you more ahead than a pair of modified small blocks. I'm assuming you plan on keeping the boat for life because of its importance, so tweaking the big blocks over the years will be a much better overall plan than a conversion now, then a complete re-conversion someday down the road because of the limits of the small block platform.

Now, this is my opinion, and I have been wrong before........

Big whats in the boat?:eek:
 
Happy Hollidays Gents! So I sold the old engine to a guy locally. He was very interested in the boat and the history of it. Very cool guy, he called and updated me that he had torn down the engine. Looks like he is going to be able to make it work. Not sure what his plans are but I think he's looking for another 420.

On another note... Ill be storing the boat outside. I got a deal through a friend and they are also allowing me to put a canopy over it. So.... whats the best bang for the buck? I was thinking of just ordering a 13x40 or 12x40 canopy but not sure which path ill be taking. I also had thought about making on my own... thoughts? probably secure it to either the trailer or get something heavy to weigh it down. The boat is in a pretty secure place that some of you might have heard of, Lockheed Martin. $50 a month :)
 
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