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STV_Keith

FS: 2 - OMC V8 Stage 5 Evolution drop ons - 430hp each, will separate

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One motor is disassembled. Both started life as a 1994 300hp V8. Modded by Evolution Marine back in 1995 to their Stage 5 level. They claimed 430hp. Intakes are ported, rod slots are done up, finger ported, etc. (see pics below)

Big bore carbs, no VRO. Rapair 8500rpm power packs. Heads are studded.

Motor 1: Compression is 125-130 port bank, 110-120 stb bank. These numbers were recorded at 2000' elevation, so add 8# to these numbers for sea level.

Motor was disassembled due to a vibration that was loosening the upper bearing bolts. 2 of those 8 bolt holes are stripped. I planned to heli-coil them, but now I'm not doing anything to it. :)

The vibration came from the crank being loose in the block. I found this while putting a different crank in it. I thought the original crank was bent, causing the vibration (which it might be), but the bearing saddles are wallowed out. They need to be welded up and line bored to spec again. Jim Ruck can do this, but I didn't get a quote for it.

Motor ran hard, right up until being disassembled. 6500+rpm, no problem (actually turned them 7200 or so when I first got the boat as they only had 20" props on them). This pair pushed my 30' Scarab 74mph. Block has not been welded on.

$1800 + shipping or pickup in Vegas.

intake1.jpg

front-half1.jpg

front-half2.jpg

front-half3.jpg

transfer-ports.jpg

exh-porting.jpg

Motor 2: This is the sister powerhead in perfect running condition. They were built at the same time as a matched pair.

This motor has compression numbers of 115-122 on the port bank, 107-115 stb bank IIRC. I have all the numbers at home. These numbers were also taken at 2000' elevation, so again, add about 8# per cylinder.

This motor had some kind of a patch on the exhaust chamber that came from the outside into the water jacket, one on each side. These patches leaked water at one point, so I had them ground out and a plate of aluminum welded over them. Did a nice job, but I didn't paint the alum when it was done. Here's what it looked like before:

port-leak.jpg

$3500 + shipping or pickup in Vegas.

$5000/pr if you buy both + shipping or pickup.

Here's a few vids so you can see/hear them run. :)

Planing off

Top end run - 6500rpm

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