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Repower costs

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shy_d

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"Hello, I think my 84 Merc 30

"Hello, I think my 84 Merc 305 is seized up. How much should I be looking at to repower?
Thanks"
 
"a short block costs about 120

"a short block costs about 1200-1500+ depending on quality and options, a long block from 1500-2500+
are you happy with the 305? or do you want a bit more. You can drop in a 350 long block for the same money and get about 40-80hp more with a 2bbl carb and 50-100hp with a 4bbl carb, all depending on options (heads, camshaft pistons, stroke, compression ratio, intake manifold, exhaust manifold etc.. the list is extensive."
 
I was wondering if the 350 wou

I was wondering if the 350 would be another option. I figured the block size is the same. Would it cost less going with a 350? And does the 350 have to be Marine spec? or will any 350 long block work?
 
"There's many ways you can

"There's many ways you can go, if I had the money and I was going from a 305 to 350, I'd go for a what's called a 383 stroker engine, but that gets $$$ real quick, a step down would be an upgrade to a 290hp 350 engine with a 4bbl manifold and carb, that cost will be a little more but you get some good gains, if you go for a 260hp and use your 2bbl carb and manifold you might only be about 240hp-250hp costs about the same, depends how close you match to the 305 as far as dipstick tube, if you upgrade to a 4bbl intake, if you get on for the same year, as there are changes 83-85, different dipstick locations, cylinder head changes, etc..

Marine spec yes, because, marine uses brass freeze plugs for the water jacket, better ones have forged pistons versus cast pistons(low quality), you can more easily get a hi-performance 4 bolt main block ( car ones are 2 bolt ), also the camshafts can be different depending on the setup. Car or truck engines aren't setup to run in the 3000-5000rpm range as much as boats."
 
"Thanks for the help, I do hav

"Thanks for the help, I do have the 305 with a 4bbl, I am in the process of getting some prices for the repower, so far it is not looking to hurtful."
 
"then if you already have a 4b

"then if you already have a 4bbl, then get a 350 for the same year, you need to watch a couple simple things, I think.

1 for a longer lasting engine, make sure it at least has forged pistons

2 if you have a mechanical fuel pump, you need to make sure the replacement has the hole and mount for a mech pump ( some have the spot but the pump rod hole isn't machined )

3 make sure if you have a RH oil dipstick, that the replacement has the same

4 even better than forged pistons is a 4 bolt main cap setup and if you can get a windage tray kit. ( the better marine engines have this, it helps with oil control in the bottom end )

5 your 305 carb shouldn't be an issue for the 350, the primary and secondary fuel jets should and typically can handle the change (as long as the heads and cam isn't upgraded to much)

6 dont accept an engine that has been bored more than .030 ( piston oversize ) this limits your abilities later if needed.

Everything else on your engine will be fine again as long as you dont go far over stock 260-290hp (though a 290 might want bigger primary jets)

good luck !! - Safe boating"
 
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