Summit Brand LS Blocks ?
 

Does any one have any info on these steel blocks 4.8 /5.3 for 399.00 with machine work done ?? Seems like a heck of a deal when I add up tearing one of ours down running it to the machine shop for freshening and then picking it back up..Time alone is a lot versus something that shows up for that kinda money and just needs a hot bubble bath , ck some tolerances and toss it together.. I would be interested in what foundry they are coming from...One of you big hitters should know someone that knows someone that slept with someones sister that now is married to a Summit Racing executive ?

Wondered this myself. I was placing an order a few years ago, and I asked my salesman if he knew who manufactured Summits gear sets, and he quickly told me that he had no idea. Probably the same with these blocks. I believe that these units even come with cam bearings installed, for this price.

They are unmachined blocks. I have already call on it and they actually changed the description because of my phone call about 6 weeks ago.

The web site says that it has finished cylinder bores.

but when you read dimensions, they are undersized unless they changed it again

My Summit description says "Factory Overstock" which I believe was an over-run of GM parts and bore is Finished 3.780 which is 4.8 or 5.3 liter finished bore size depending on which crank you drop in it. Woops the Summit on line description says "Summit brand block" but finished bore "yes"

I guess I can order one and see what it is when I get it. I am however very curious as to the origin of this particular block, it is not a motor that has a huge high performance(build platform) following nor do I see it being a huge replacement block market for standard repairs.( most are still running ) It would be easier for me to believe they bought a bunch of overstock ( phased out of inventory) blocks from GM..I cant see anyone tooling up to make an aftermarket iron block that had no improvements or raised deck height that didn't have a huge standard replacement need for daily drivers ? STRANGE...
I will check with some friends that own machine shops and see how many LS motors they are doing standard rebuilds on.. These days the motors outlive the vehicle...

I wonder if these are from ATK? Summit sells a 6.0 LQ4/9 block that is .030" over and supposedly finish machined that they get straight from ATK. Those blocks are seasong (used) blocks that have been cleaned and bored.

Here is the listing for the 6.0 block:

http://www.summitracing.com/parts/SUM-150105/

Here is a thread on ls1tech detailing the 6.0 block:

http://ls1tech.com/forums/generation...-ls-block.html

There were som naysayers in that thread but overall it seemed like most were pleased.

Yup that's exactly what I was thinking...

After thinking about this, your probably right about these simply being over stocked blocks. The LS series is done, and GM has moved on to producing the new LT stuff, so it makes sense.