aftermarket 346xp top end on a 350

[JT78]

I need a new piston for my 350 but noticed a couple decent looking aftermarket topend kits for 346xp just wondering how much more I may pick up power wise by using the aftermarket kit vs the 350 piston cylinder. I should add the 350 cylinder is already ported but I plan to port the 346 kit if I get it. Also have a question having never pulled apart a 346 I understand its closed port, does it have a windowed piston? Any feedback would be appreciated.

[SawTroll]

That will like to a large degree depend on what aftermarket 346xp top end is in question - they vary a lot both in design and quality! I am no expert on aftermarket top ends though, so don't ask me which one to use - I would use an OEM one.

[JT78]

The one I was looking at is made by hyway and has a nikisil coating I understand they are not mahle just wondering if the difference in power is worth an extra 80 bucks. Also does anybody here know if the 346 piston is a window piston or full skirt?

[JohnG28]

346 piston won't work. I'm finishing a build on a 350 now, use a 353 flat top piston instead of the dished normal piston for a compression boost. I got a meteor piston for $40 and it's nice looking,  better than the oem piston IMO. I'm going with no base gasket, measured around .020 squish clearance without it. Did a little port cleaning and slightly opened the transfers and exhaust. Not back together yet but should be soon. Pretty cheap way to go and others who have done so say it's a good improvement. If you decide to go this route pm me and I may be able to help you out.

[SawTroll]

346 piston won't work. .......

He asked about a 346xp top end - not just a piston!  ;)

[JT78]

I still very much appreciate the info you wouldn't happen to have a part # or link to that piston would ya also mine is the older 44mm piston not the newer 45 so don't know if that will change things cause I think the 353 was 35??

[JohnG28]

Apologies on the piston only, thought the end of your post was asking about the piston only. I was referring to the newer 45 mm piston,  it shares (almost identically I believe) the 353 top end. The older 49 cc one may fit a 346 piston and they had a windowed piston I believe and were also 44 mm.

[Spike60]

There are several changes that need to be made to the case and hardware in order to put a 346 cylinder on a 350. Nothing major, but it's not just a straight bolt on.

[NCFarmboy]

There are no windowed pistons in 340,345,346,350,353.  340=42mm, 345 and some 350's =44mm, 350 and 353=45mm (350 is dished, 353 is flat top), OE346= 42mm, NE346= 44.3mm.  The Hyway kits have gotten some rave reviews.  I plan on getting a Hyway kit for 359 Husky it's closed port like 357.  You could really call it a BBK for 357.  IMO the NE 346 kit is well worth the $80.  I've got 2-350's I'm converting when I get round to it.
Shep