Looking for information on the performance potentials of these engines.

Me Too.

There is a lot of discussion and build threads about them HERE.

The comp eliminator racers are making > 100hp/cylinder in NA form.

The engine can easily make 400HP turbo'ed and good fuel. What do you want to do with it?

The 2800 is the 4 cylinder version of the 4200 and uses common parts with the '02 to '05 4200 (except the cams and crank). The 2900/3700 got a bigger bore and uses the same valve train parts as the '06 up 4200 except for the camshafts.

To bad GM did go to the bigger bore on the 4200..

I recently got a 2900 donated to me..

Having a bigger bore allows the cylinder head to flow better. What could be wrong with the 4200 bore size?

I think he's just meaning in a generic manner that there is always room for improvement. However, Leo's new engine makes 1150 HP with a mild tune up, so I don't see anything wrong with the bore size up to this power level.

I'm just wondering about a Colorado or what ever small 4X4 pickup with a 2800-2900 four. (odd #s of cylinders doesn't work for me)

I don't know what Leo's new engine is. I'm not racing just trying to get home. The wife's 2014 Jeep just impressed the heck out of me with it's V-6 and "Trail Rated" electronic 4X4. It came up the 2 miles of snow over mud better than 1,500' of elevation in 2 miles as well as we have done in the past chained up on all 4 in older rigs. I'm wondering if a Colorado is worth thinking about or just stick the 292 in the old '70 blazer add deal with it.

Leo has switched over to Atlas power with a 4200 in his Stude.

Nothing wrong - just wishful thinking. When GM update the 2800/3500 they went to a bigger bore - 1 year after the 4200 got its mid-life upgrade.

I'm pretty good at wishful thinking. It's actually doing things that challenges me.

Tom,

You would be surprised at what a 2900 will do.. add a freer flowing exhaust/cat delete & tune and I think you would really like it. You could find a 3 pedal 2900 colorado/canyon 4x4 with the Z71 option.

I get around fine here with my 2wd with posi and good snow tires no problem.

I need to find one on a car lot and take a test drive.

I had an 04 4cyl colorado with a 5 speed and it moved just fine. And I drove it in the mountains a lot. I think it would be lots of fun with a turbo on it.