davo

Does anyone know whatthe max you can bore out a 5.3 iron block?
I have it bored right now to 3.898 but would like to know if it safe to go to 3.905. Or could it be bored even more due to its an iron block?

Thanks David

Hemi Killer

iTrader: (6)

I think you have to get it sonic tested, that's just what I heard...

Evil F1 SS

Mine is 3.905 and has servived a while.

dacajun

iTrader: (19)

My info on this supports the above 3.905. However I have the same question can this go to a 4" or above bore? And as Hemi killer stated, the answer to this is to have it sonic tested to determine cyl. thickness. Although I have read somewhere that these blocks can go 100 over I have never seen anything to support that claim.

-Dave

Uthinkso

Same as the 5.3L aluminum blocks, 3.905" is the limit.

zo6vetteman2003

iTrader: (1)

I believe the max. safe bore is 99mm up from 96mm stock. This is a 5.7L, (3.893" bore). The problem is the .100" cylinder liners. The stroke also needs to be 3.662", so you can reuse the stock 3.662" crank, or install a forged one. I don't have any other info., but this is what it said. All LSx series heads will fit this block. The stock ZO6 cam will fit without any problem, so alot of cam selections are available. I believe with the stock heads (61.1cc combustion chamber) will make more power than the LS6 stock heads, unless the LS6 heads are milled and a piston change would be needed to get the compression back up.
Hope this info. helps. The book I used for this info. was the Will Handzel book.

kickassT/A

iTrader: (3)

what?

zo6vetteman2003

iTrader: (1)

You can safely bore a 5.3L out to make it a 5.7L. That doesn't mean 3.905" isn't doable. Your just .012" overall, further into the .100" cylinder liner beyond what GM Performance Parts recommends.

Nate_Taufer

iTrader: (1)

You do understand we are talking about iron blocks here don't you? Iron blocks don't have sleeves. I have pondered this myself as the 5.3L is still on a 4.4" bore spacing and could technically hit 4.0" if it didn't hit water. I really don't see why it wouldn't work unless the water jackets are too close.

zo6vetteman2003

iTrader: (1)

Yeah went back and saw iron, sorry about that. It says here that 5.3 Liter iron blocks (LM7) can be bored out to a 3.893" bore. The 6.0L block's 4.00" bores are max. for the wall thickness. I interpret this to mean that a safe bore on a iron 5.3 is 3.893", max would be 4.0"

PREDATOR-Z

What do you mean by that? You can bore 6.0 Iron to .060 (after sonic testing). Mine is bored .030 for a 4.030 bore and 370 CID.
(BTW I've seen a 6.0 bored .080 but those are far and few between)

zo6vetteman2003

iTrader: (1)

It says here "The 6.0L engine block's 4.0" (101.6mm) bores are nearly the max. for the wall thickness, so it isn't recommended to bore these out for more cubic inches." It sounds like you have a slight bit of wiggle room that you indeed took, seeing it says "nearly the max."

PREDATOR-Z

You can bore 6.0 iron "Very Safely" to .030 and that is common practice, like I said .060 needs Sonic Test and beyond that is race only for custom strokers.

davo

So I take it that it is safe to punch the 5.3 iron block I have to 3.905 safety without any problems? I want to pick up the 383 kit from Summit racing part number ESP-B12804STD.

I had my 5.3 block machined to 3.898 and then decided to make a change. That is why I asked the question about taking it to 3.905 safetly.

Also is this kit from Summit racing a good kit??

Thanks for all the help in advance..
David

zo6vetteman2003

iTrader: (1)

I would look into this further, due to the two seperate casting numbers 5.3L and 6.0L just to be safe.
P/N 12551359 (5.3) and P/N 12551365 (6.0)

Predator Z, I've seen your postings for a long time now, your very knowlegable. If you have safely done it, then it can be done without problems. Sonic testing must be the real recommedation here.

Evil F1 SS

Well if it helps my 5.3 Iron block has had a 3.905 bore for a while and is a boosted car that puts down around 840rwhp. 3.905 is safe if you ask me.

yobabiesdaddy2001

iTrader: (20)

If you are getting 800hp out of a 5.3 iron block then I might try one?

Bo White

iTrader: (59)

I know of quite a few 383 "5.3"(3.905 bore/4.00 stroke) engines that are in std cab short bed trucks and some are sprayed/boosted like was said above. The 6.0 being bored .030" over...wouldnt think twice about it...very safe.

bgoedeker07

Those cylinder walls are thick as hell. You should measure out 3.905 on your cylinder you might be surprised to see how small of a difference it is from 3.78 to 3.905 is. Anyways my machine shop guy actually talked me into going to a bigger bore size. Oh and you can always sonic test the walls if your worried about it. If it fails the test, you get to have the fun of pulling another 5.3 from a yard.

G Atsma

You DO know this is an 11-year old thread right?