Help me decide which engine
 

I have been talking to Katech and MTI racing on motors. The following are the two choices I'm considering but cant make up my mind on which way to go. Any input or suggestions would be greatly appreciated.

This is the one from MTI:
Built 6.6L Stroker engine
LS2 based
Forged pistons, forged rods, balanced and blueprinted
MTI Racing CNC ported heads
Ported LS6 Intake manifold
MTI Racing/Comp Cams private label Camshaft
MTI Racing lightweight valvetrain (valvesprings, locks, retainers, seals, seats)
comes with valve covers
comes with oil pan
550-575hp depending on cam aggressiveness

This is the one from Katech:
Estimated 650+hp
7500rpm redline
427ci
LSX based
Carbureted
Includes Katech valve covers, coil relocation, coils, electronics, and carburetor

I would go with the LS2 based motor in a pro touring car as you save a bunch of weight over the LSX based motor. For dragracing I would do the LSX based motor.

Tonny

Some basic truths that may help your decision:

A bigger displacement engine doesn't have to work as hard to make power.

A lower-revving engine will outlast a higher-revving engine. RPM is hard on parts.

So, if you go for a larger-displacement engine that redlines at 6,500 rpm, it will outlast a smaller-displacement engine that redlines at 7,500 rpm.

You may not be considering longevity as part of the plan right now, but maybe you should be. This engine will require significant investment, and an engine that requires rebuilding in 3 yrs vs. one that requires a rebuild in 6 yrs is worthy of consideration.

I like big-inch engines that are done by 6,500 or so. I like iron blocks (yes, they weigh more. The also don't move around as much with temperature, and you'll be getting internal coolant and oil temps up pretty high in an engine like this.) Once you start moving past 7,000 rpm, stuff get's pushed pretty hard.

Just some stuff to think about...

Both companies are solid and your choices sound great.
I would go with the Katech engine, just because it's a carb'ed based LSx. I like that. ALSO, Katech has a killer reputation. MTI does as well, but I like the options on the Katech engine. 427 LSx = good stuff.:thumbsup:
GOOD LUCK!!:cheers:

Need more info..

No mention of crank.. I assume forged but who's? Big price differecen between say a Lunati (made in USA) and a crank forged and machined overseas.

On the Katech unit, is it LSX as in the iron GMPP block? Which style heads (cathedral or rec like in the LS3 head)...

On the first engine which oil pan.. which valve covers..

I would focus more on quality of parts than on marketing terms like displacement and such.

Yeah it's a cast iron block, I had talked to Jason about this some time ago.
As for choice well that is kind of up to you isn't it? everybody has their own opinion.
Try and do some homework on them to form your own opinion.
I know it is hard knowing where to begin sourcing info..
I struggle with that as well, maybe someone can guide you in the right direction.

it depends on your use of the car... autocross/canyoncarving.. the ls3 based for sure... street use, long trips, ... possibly the iron engine...

take a look at MAST motorsports, they can do you a supercharged engine for about the money katech charges..

Yes, these are some of the questions that I need to ask. I am also very comfortable with Katech knowing exactly what's needed to put an LS motor in a 69 Camaro as they did my previous motor. Not sure about MTI as of yet on the 69 application, they have built a few motors for my Z06 but that has been my extent of dealing with them.

Just some food for thought, check out Wegner Automotive. Depending where you're at Prodigy reps Wegner. They are hooked in with NASCAR and longevity will not be a problem. Great bang for the buck!