Mast Motorsports 427 v. Katech?

[Corinthian]

Hi, I'm looking at motors for my project and I was pretty sure I wanted to go with Mast's http://www.mastmotorsports.com/2010/product-view.php?cat=Black%20Label%20Brand%20Engines&id=155 black label 427, but lately I've been hearing really good things about Katech.

Most of my research on Mast brings up magazine tests but not much real world stuff. DSE seems to be having good luck with the Mast motors, but from what I see Katech has a more real world track record. I guess I'm just on the fence and looking for final nudge in either direction before I drop way too much money.

I plan to drive this on the street as well as regular HPDE and some autocross.

Also I had a Q about O2 sensors, a buddy was saying that they are only needed in swaps to modern cars, but I thought they were a must for FI. Putting aside the fact that most packages come with O2 sensors and it's part of the harness, why wouldn't you just do it?

Car facts:

1969 Camaro
T56 magnum
3.73 or 3.90 gear

Thanks for the help!

[71RS/SS396]

Here's another alternative http://www.kurturbanperformance.com/ he doesn't list his engines on his website but he does build a similar package to the Mast one you posted. Ask Finch how he likes his if you want some real world feedback.

[rocketman]

Mast or Katech there 2 of the best engine builders out there can't go wrong with either.

I have had a Mast engine and it was an awesome piece. I have used Katech( not an Ls engine thou) and they are well built also.

[68sixspeed]

Katech just based on race experience, spintron testing of their cam packages, and they helped develop the LS7 with GM.

[armourmark]

You will need the front O2 sensors.