Re: Shortblocks - Buy, Build, or Rebuild - Looking for opinions, experience...
 

Starting to plan for the future here... looking best bang for buck but be more than I need for my goal power wise. (650-700whp)

Options
#1 - Rebuild current LS1 w/forged parts
My LS1 has 100k right now. If I yank it out I would have it built to handle 800hp but won't come near that. Add aftermarket cam, use the 317 heads I have now.

#2 Buy off the shelf built LS3 rated for 800hp add my 317 heads guessing I will need new intake mani, tb setup...

#3 Build a (used) shortblock 5.3, 5.7 or 6.0L to handle 800hp.

I don't know how to build motors or yank them out so labor will be added on top of parts.

So, end of the day what would be the best route, down time not a factor as I don't drive the car much now due to bad AC compressor and shitty FLA weather...

If I'm overlooking major cost somewhere clue me in please!!

I'd buy a " junkyard " iron 6.0 shortblock, order a custom spec'ed cam and valvetrane for your 317's. Then drop it all off at your builder and have him machine the block to be certain there's no cracks and all the surfaces are square. I'd have him cut and use the factory crank, get some ARP bolts, get new rods & Pistons/ rings for your combo. New oil pump, timing chain , balancer, pin the crank, ls9 head gaskets .

Are you planning to do a supercharger

I'm about 8k into my longblock. 390ci iron turbo longblock from AES. I did the engine swapping myself on the garage floor. No lift.

Thanks for the reply, yea I have a Frankenstein kit and fuel system for E85 that should be good for 800hp. Decided to do the motor first. Guess i'll start pricing parts out now. Definitely don't want to be in this thing for 8k though ouch!!

Yea, It's a hard hit but my motor has some nice parts in it. I wanted to do it just once. The builder said he has the same shortblock in another car and it's already been north of 1200 RWHP

I built a free 4.8 ls with gen 4 rods with good bolts, forged wiseco 040 over pistons, std factory crank

factory short blocks are very strong and the 4.8/5.3 no one wants make good power and can rev to the moon with good heads small bore size can limit valve sizes though

it's for sale, see my add in c5 section will handle 800 hp all day, and is quite affordable

the ls3 is great if you are staying head and cam but expensive

I have a turbo solution for that level of $$ pm me if interested

Do you have any pics?

I haven't read or seen much on 4.8's going into C5's all that much. Is it the same with other GM blocks, anything unusual about the install? I'm assuming I wouldn't want to use or even can use my 317 heads with your motor since yours is already at low compression. Would I need to get 243's instead or use my LS1 heads just rework em? Is a motor built for a turbo setup good to use with supercharger type FI? I admit the price is enticing...

Sorry for the noob questions...

I think they're passed up for the 5.3Ls but otherwise the same block. IIRC since the LS1/6 blocks aren't available shops will use the 5.3 block to make a 346/347.

I've read about too many people breaking their LS3 blocks and after speaking with Steve @ RED, I now understand why. I'm a big fan of the iron blocks. They usually don't add as much weight as most people think and they're much heartier than their aluminum counterparts. I owned a forged 6.0L setup for a couple years and beat the piss out of it, making over 1kwhp on pump gas. It broke a valve and I took it out and parted it out.
I use one of 2 engine builders for my engine builds. I really like them both because they care and pay close attention to their work and care enough to not let any sloppy work leave their shop. Lots of talented shops out there that have lost their desire to take the time to do it right. I not only sell the engine parts, but I often spend hours consulting with my customers to make sure they get what they need. I don't push things on people, rather help them make decisions that best suit their needs. PM me if I can help.
:cheers:
Bret

Cheapest will be to upgrade your existing block. And at 800hp, that shouldnt be an issue.

As for heads, if you re-use your old heads, there is no need to change intake or anything relating to it regardless of what bottom end you bolt them to.

If you are not doing the labour etc...then there probably isnt much benefit to buying another motor to rebuild.

Just drive into a shop who can do all...and let them do that with your current block.

Although new blocks are relatively cheap and if you've a motor sitting waiting that can speed up the process and you could always keep your old one as a spare.

If people would just listen to you and quit changing their mind life would be so much more simple.:crazy:

I like the way you think!

I think it's about a 60 or 80 lb difference and a whole bunch more peace of mind.

My experience comes from linehoning them Boring & or cylinder honing them and decking them and it's incredible how much the aluminum moves around compared to the iron. So in my little head I think ok if I'm torquing main caps or a torque plate and I see that much movement, what's going on at 6,000 RPM or higher with a bunch of boost on top of if.

It makes me shudder to think about it.

My personal belief is that once you break 600 hp with a boosted LS1,2,3 its time to go to an iron block. Again josh my belief and I know they get pushed harder much harder all the time.

Aluminium will handle 1k easily. There may be some "bad" blocks out there, but they must be few and far between.

And it does seem there are quite a few guys who have burst cylinder walls on 6.0 iron blocks too....

The strongest factory aluminium block, if you have the money go for the LS9, which will already have oil squirters and stronger pinned main caps and 12mm head fasteners vs the 11mm

600hp shouldnt be troubling any block though. I wouldnt even consider iron until well above 1k, and even then it would probably end up being LSX.
But sub 1k...unless you got the iron block for free or something I see no reason to consider it.

Thanks for all the replies back, I learn a lot from you guys in this section. However I just received my planned budget back from the board and it looks like I'm going to be building my current LS1...

So now, a new set of questions.

Who to use for piston and rods?
Do I want dished/domed/flat for boost (using 317 heads with LS9 head gaskets)
I do know I want to get one of Englandgreens lines of cams, I get giddy every time I hear one of those cam vids and the car is lopey AF!
Should I spend the $$ on ARP fasteners?

If you're buying a cam from EG, I presume he could spec and supply any other items needed ?

You need pistons with a dish to create the compression ratio you want for your setup.

And yes ARP studs etc pretty much always make sense.

I went with Callie's crank and rods, coated Diamond Pistons with full ARP hardware.

hi folks if anyone wants "lil thumper" here she is

https://www.corvetteforum.com/forums...-engine-2.html

bret,

I'm thinking of doing an alum l33 style block and really debating using that block vs iron block I have both and my goals are 1k hp and I would love an ls9 block but they are too much $$$

I have also been looking hard at the LS Next block as I do have a set of 6 bolt heads.

I probably should just throw lil thumper in there and call it a day!!

Interested in how you like the haltech!