FWIW, my 98 LS1 that had 172,000 on it looked almost identical when I tore it down. After a simple rebuild, cylinder hone and a crank polish, new bearings and rings, it's working great. Mine even had the 806 perimeter bolt heads like those, which ended up in the aluminum scrap bin as they aren't worth anything. Found a set of cheap low mileage 241's on craigslist to replace them. Not the best either, but the price was right and they looked new.
A Compcams trunnion upgrade will take care of the rockers too. Good luck, cool project!
I've had several motors rebuilt -- and have also bought "crate" motors (if you consider (Smeding Performance a crate motor - which I do). It - like most things - comes down to QUALITY - and QUALITY doesn't come cheap. In order to get the costs down - production has to rise - or corners have to be cut. And like most things -- it all depends. Depends on how you plan to use it. Frankly - you don't need much of a motor to cruise around to car shows... you need a completely different build if you want to hammer it on the drag strip.
A really DECENT motor is the HO350/350 from GM.... you can get one complete carb to pan - including distributor and spark plugs even (the distributor needs to be recurved!!) for very little money. Smeding Performance has some variations of horsey power and use -- also pretty affordable and complete.
Some crate engine builders actually offer a warranty - nice peace of mind....
Or a simple rebuild or yours... like RickPaw pointed out - just do some comparison shopping.
Another thing to check is warranty from rebuilt engines vs GM crate engines. GM crate engines have 24 month warranty (there maybe fine prints). Rebuilt engines may not have warranties. My engine builder said when I picked up my rebuilt short block/heads years back that I have a 10 step warranty (10 steps out the door then I'm on my own).
I had never heard of them until the other day and it might just be a one time fluke but here is my experience.
I saw a stroker moter come out of a crate and had visible aluminum chips where something was ground on after it was assembled and there was a sandy grit all in the motor (beads from a blast cabinet?) I just know there is no way in hell it would ever be put in my car without a complete dissasembly, cleaning and inspection.
I have heard of Thompson, never dealt with them directly, but reviews have been positive.
On that motor, I am not entirely sure I would want to take a 5.3 and bore it out to 5.7. I know the iron 5.3s have thick cylinder walls and can take it, but I have always been against enlarging cylinder walls, just to enlarge them.
For the price you are going to pay for that one, why not look for a completely stock 6.0 with low mileage. If you search hard enough you will be able to find one with under 10K miles, that technically hasn't even been broken in yet, for less than the 5.7 you are looking at.
Your car, your money, just my opinion.
__________________
'89 IROC-Z Turbo 3.8 5SPD
LS1 Brakes|Wilwood Prop Valve|LS1 Master Cylinder|Aluminum Driveshaft|LS1 3.42 Rearend|Adj PHB|Adj LCA|LCARB|Koni Struts|Koni Shocks|Adj Caster/Camber Plates|STB|10 Spoke SS Wheels|PHB Relo Kit|Adj TA|SFC|ARAP Based Prom|B&M Short Shifter|Underdrive Pullies|SMOG!|AIR!|Rag Joint!|Magnaflow|Ported Plenum|Misc Stuff
Check out the Texas classifieds section on ls1tech. There are a few ls1's for sale on there now. Short block and long block configurations pop up for sale fairly often. Rebuilding seems to get expensive quickly, unless your planning a stroker or big power I would look for a low mileage 6.0 as mentioned above, prob your best bang for the buck
Brian Hobaugh SCCA National Tour June 2014
First Hemi 'Cuda Convertible Ever Built
Short clips: Goodguys Pleasanton autocross and pit videos
Hybrid Mode
