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Thoughts on 30 swap

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baba_bluey

Regular Contributor
"Right now i have a 1980 470 i

"Right now i have a 1980 470 in the boat. Been putting band-aids on the boat for a few years now. Wanted to drop a v-6, or v-8 in, but i think there will be a weight issue. So i'm looking at the 3.0 right now. What are your thoughts on this motor? It would be going into a heavy 22ftr."
 
"Well, the 3.0L 181ci range fr

"Well, the 3.0L 181ci range from 135hp to 140hp when brand new which is less than the 165-190hp from the 4cyl 470/488 224ci engines. the V6's 4.3L 262ci get from 175-220hp.

With the 4cyl you may not need to change much for the mount but I think the engine is a little shorter. for the V6 or V8 you'll need mounts on the sides of the engine. I think the V8 is about 100 lbs heavier than the V6.

I've seen 3.0L's in heavy 21's it's not bad but tops about 32-35mph in calm water.

Going from the 470 to a V6 may be about 100-150 lbs, but you have more torque and hp to play with.

Also doesn't the 470 use a 1.65:1 (inline 6) or 1.8:1 ratio drive? same as the V6 a 3.0L uses a 1.98:1 ratio drive, so you would need to drop the pitch on the prop.

If you go with a 4cyl 3.0L I'd get new, not rebuilt or remanufactured. If i went V6 i'd get used but low hours newer then '93 when they went to the "balance-shaft" block, a little smoother running, I could go either 2bbl or 4bbl carb (190 or 210hp)"
 
"Thanks for the input Brian. T

"Thanks for the input Brian. The stern of my boat sits alittle low in the water, that's why the v-6/v-8 is out of the question. My boat only tops out at 24mph. Tried changing props too. And that's at 4400rpms."
 
"The only difference in outdri

"The only difference in outdrives from a 470 to a V6 is the gear ratio, I think you have a 1.65:1r like mine, a V6 drive is 1.80:1r and actually with the HP gain you might be able to stay on the same prop maybe drop from a 19p to a 17p or a 4blade 18p. 24mph is a little slow for a 22' considering my father in laws does 32-35 with a tired 140hp on a 19p prop. Maybe you have some extra weight in the boat ( hidden water maybe? )

I used a 4cyl drive 1.98r on my inline 6 1.65r and went from a 19p to a 23p!! prop for a while, no problem, came out of the hole quicker and wasn't even using a marine cam so I was @ 110hp instead of 165hp. and still did 35mph ( with a 21' alum cuddy boat)"
 
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