Do they use their own gears or mercs?

I've heard nothing but good things also. It seems they are well made. A guy at our local lake busted his Alpha 1 and was going to order an SEI replacement but they would not honor the 3 yr warranty if the Alpha was behind a 454BBC. He ended up going for a Merc reman on Ebay.

Their own gears. The patent ran out on some of the Merc drives.

?? the alpha 454 was oem, though for a short time...

Yea the boat is a 87 22 Baja Sport 454BBC Alpha 1. He called SEI and they told him no on the 3 yr no fault behind a BBC. They would only warranty the Alpha with a SBC.

Can you get a warranty on a new OEM Mercruiser Alpha drive behind a 454 now though? Or are they also only warrantied up to 300 hp now?

I am going to stick my neck out here, but I would think if it is one of the factory 454's that came with an Alpha it sure would be warranteed.

My assumption was that before the bravo drive they figured they'd absorb any additional warranty costs with the profits from selling the whole engine/drive packages but I thought even the OEM alpha drive purchased a la carte was warrantied only up to 300 hp.

I'm slightly curious as I currently have a pair of 350 mags but at some point would like to get some more speed. For now I purchased a pair of SEI116s and am pleased by the price for what you get. I figured even if I went with OEM now, that warranty is only for 1 year unless you have them installed by their certified partner builder list so it would be up before I got new engines. The SEIs have a 3 year warranty which is great but I'm limited to 300 hp if I replace the engines in that time... though even if I voided the warranty later on the OEM warranty would have been up anyway, so it was a win in the short term and maybe a wash in the long term.

we have also been using sei for alphas and bravos without any problems to date. The only thing that is weak link is alpha water pump impellers seem to spin the hub prematurely. replace w/ merc kit and no problem

I've been beating the crap out of the alpha version for two years. and as above the water pump failed... after about three weeks. otherwise, it's working like a champ. know a number of others with similar experience.