430 hp 70

iTrader: (3)

guys, some will say to search, but after a few hours im not much further. im looking for gen 4 5.3 aluminum parts #s. so far ive found three; 12566910 and 12571048 for RWDs and 12569004 for the FWDs. just wondering if anyone knows of any other part numbers that will work.

i plan to call steve at RED again tomorrow, but last i talked to him he didnt have exact part numbers, just said to get a gen 4 block.

thanks.....

Che70velle

iTrader: (6)

Tim, what block is that in you engine bay? It looks aluminum in the pics. Stay away from the fwd blocks. They won't work for what your going to do. If your going to sleeve a block, look into a used ls7 block. Just about every one you'll find needs a sleeve. It's often number 7. Hmmmm. I'm also glad your back on your feet, and working on the car again. Your build is what inspired me to build mine. Can't wait to see yours finished.

430 hp 70

iTrader: (3)

its a gen 3 block that im using for mockup. steve at red said they can only be wet sleeved which is a bunch more money.

i did read that the fwd blocks are alot different. i was hoping the block was the same with a different accessory drive etc, but its not even close.

id love to run a ls7 block, but ive been told the gen 4 aluminum truck blocks make the best starting point for a sleeve job. if i could find a ls7 block for close to the same price i wouldnt mind, i just dont ever see them cheap.

btw, thanks for the words. feeling much better now and want to get this done......

430 hp 70

iTrader: (3)

just found something listing 12571048, 12601900 and 12568573 as the 5.3 and 12568952 as the 6.0. both sets aluminum gen 4 truck blocks. it did not list the 12566910 which is one of the blocks steve at RED recommends. i talked to him yesterday and he said to be careful because there are some blocks that are a hybrid between the gen 3/4 (edit. he says this is the 12569513). it sounds like they look like a gen 4 with cam sensor placement, but use the gen 3 cylinder setup and cannot be dry sleeved.

430 hp 70

iTrader: (3)

well after actually checking the number on my block, it appears to be a gen 4 6.0 truck block with the 12568952 stamped in the back. im also not seeing any cam sensor hole in the top, but rather the 8 little "stands". problem is its not mine (i borrowed it a few years back) and was told it wasnt any good. any good with a bad sleeve or any good with a crack i have no idea. im going to pull it next week and give it a good look. heads and exhaust are bolted up right now so i have no way of seeing anything.

Che70velle

iTrader: (6)

Thats great news! I'll bet it can be had for a great price.

430 hp 70

iTrader: (3)

well i pulled the heads last night and found the issue. there are 3 "nicks" in the deck surface with the worst being about .040 deep. they are all between the lower bolt and the edge of the deck on 3 cylinders. in addition, there are 3 nicks on the front of the block. one where the front cover would seal, one where the water pump would seal and another that doesnt look like it would matter. just not sure i want to chance having an issue. im going to call steve and see what he thinks and how much he would be decking anyways.

edit. called steve and he said the deck is not an issue and the front can be worked around. now i just need to find the guy that loaned me the block and make he still wants to sell it. if not, steve should be coming across some in the next few weeks.

430 hp 70

iTrader: (3)

just updated to change the 12569513 to the gen 3/4 combo which is according to steve.

Later-A-body

iTrader: (1)

I have a 430" LS motor based on a Gen 4 5.3 block that I had ERL build for me. If you need a source for the block, call Shaun at SMC Performance. His number is 248-276-0483. I purchased my 5.3 from him last year. He has a lot of other parts as well which I purchased from him.

LS6

From the thread I understand that block casting number 12571043 & 12571048 are good for dry sleeve. How about 5.3 GEN IV block with engine code as LH6, with the following casting number:

P/N: 12569513

P/N: 12601900

Are they good for dry sleeve?