Chicago TDP

iTrader: (3)

So, I pulled the 5.7 Ls1 out of my Turbo Nova project car and ended up picking a good 5.3L truck motor. I figure I can take this motor to its limits, hopefully not kill it too much and in the mean time, sell the aluminum 5.7 L and get a 6.0 to build.

My question is what head gaskets should I put on? I have a set of fresh 317 heads that have been dusted .003" to square up the deck. It seems the searches that I have done say put a set of 6.0L MLS truck gaskets on.

What does the masses say???

Also, where should I get them from???

Thanks for any help

Adam

fenix999

iTrader: (17)

new 6.0L GM gaskets and call it a day. Buy them from the dealer or scoggin dickey, or anywhere that sells 'em the cheapest basically. That part is up to you a million pple sell head gaskets =)

Chicago TDP

iTrader: (3)

What about the gap due to the gasket being larger then the bore of the block?
Will that be an issue?
I am not saying that it is wrong, I am just looking to figure out what is going to "work".
I guess I am looking for the guy who has "been there, done that, still running it" to chim in and say buy "_____" from "__________" and you will be fine.

But 6.0L MLS is what I am looking at right now. Except, local auto parts stores what $70 a piece

NemeSS

iTrader: (127)

I got ls9 gaskets with 241 heads milled .010 on my 5.3 the scr is around 9:1 with the ls9 gaskets and ls1 heads
Thr gaskets were 90$ shipped including gmpartsdirect inflated shipping charges. The local dealership wanted 148$ for same gaskets plus I had to wait almost a week. They prolly get em from same warehouse as just bout everybody else in the nation

408trans_am

iTrader: (263)

I would definitely just go with the ls9 and call it a day. I have had great luck with the ls9's. Those 317 heads on a 5.3 are going to be seriously low compression, probably in the low 8:1 neighborhood. 317's are 71.24cc chambers and 5.3 stock heads are 61.37cc.

Hi Volume

iTrader: (3)

5.3 w/ 6.0 heads is gonna be somewhere in the lower 8:1 CR range right? aka super low, which isnt neccesary (sp) to go that low honestly...

408trans_am

iTrader: (263)

Yup thats correct. Its definitely not needed to run that low compression, will it allow you to run more boost? yes, but when your not in boost the car will not be very efficient and probably a little "dogish" Either way, the stock rotating assembly is the weak point, so i personally would run a little more compression and less boost if it was any sort of street driving car.

MillsMotorvation

I agree!

Chicago TDP

iTrader: (3)

The 5.3 does not have dished pistons though, they are flat just like the pistons in my 5.7 aluminum motor....

Also, the 5.3 pistons come all the way to zero deck height. I do not see how they can be lower compression then what I would be running in any other engine.

I am not an expert obviously and am willing to listen but this is what I am seeing with the engine on the stand.

Chicago TDP

iTrader: (3)

The 5.3 does not have dished pistons though, they are flat just like the pistons in my 5.7 aluminum motor....

Also, the 5.3 pistons come all the way to zero deck height. I do not see how they can be lower compression then what I would be running in any other engine.

I am not an expert obviously and am willing to listen but this is what I am seeing with the engine on the stand.

408trans_am

iTrader: (263)

Kinda hard to explain but the reason being is the bore size is much smaller. With a smaller displacement, you are not trying to force as much pressure into that given space. Here is an example...

Total Displacement/ # of Cylinders = Displacement per cylinder. This total needs to then be compressed in the chamber. multiply this by 16.387 to convert to cubic centimeters (cc) ex...

Ls1 = 346ci / 8 = 43.25ci x 16.387 = 708.738 cc
5.3 = 327ci / 8 = 40.875ci x 16.387 = 669.819 cc

If you put the same head on both these motors( given both have same headgaskets and same deck height and piston height) The ls1 is compressing 2.375 more cubic inches or 38.919cc of air into that same size chamber.

So back to your scenario(again this does not account for gasket thickness, deck height, or piston height) Just so no one take this as actual measurements, its an example. with same variables comparing 2 displacement engines.

Displacement per cylinder is getting compressed into the 72cc chamber of a 317 head ex...

Ls1 with 317 head... 708.738cc / 72cc = 9.844 : 1 compression ratio
5.3l with 317 head... 669.819cc / 72cc = 9.303 : 1 compression ratio

Hope this can better explain why 2 different motors, even both having flat top pistons can have very different compressions. This is even more pronounced when people get into the 400+ci. This is also why a smaller bore engine like a 5.3l has 61.37cc heads from factory and 6.0 have 72cc heads and both motors are close to the same compression.

Chicago TDP

iTrader: (3)

So I will be .5 C/R lower then my 5.7 by going with the 5.3? Doesn't sound too bad!

I see how it is factored now. I am a little rusty but it is all coming back to me now....

So, who has a LQ4 or LQ9 for sale? LOL

I might just run this little motor for ***** and grins though as I do not want to blow up my 5.7 aluminum engine. I am going to build a 6.0 either this summer or over the winter, just need to find a core or good engine. Also more time; I have to finish putting my Harley back together

Thanks for re-educating me, been a while since I have gone through this stuff (10 years or so) LOL.

Adam

408trans_am

iTrader: (263)

Its probably a little more with all real factors accounted for. I would say somewhere 8.2 : 1. Its not a terribly bad thing as you can run more boost to make the same power. But just cruising and non boost driving the motor wont be very efficient and not as responsive and crisp. You will be fine running it.

Chicago TDP

iTrader: (3)

Well hit me up if you score a 6.0 L short block or complete! I will gladly upgrade and give out a finder's fee!

Adam

cjmatt

iTrader: (4)

317s on a 5.3l give you 8.6:1 compression

NemeSS

iTrader: (127)

U got a newer 5.3 with flat top pistons. If not then it's prolly a 4.8 and not a 5.3. What yr is the motor? Both 4.8/5.3 share same block
Different length rods
Different stroke crank
Same compression height pistons. Most ls motors are usually .008-.010 out the bore pistons

tripblackls1

iTrader: (11)

+1 on it being a 4.8, which it will be about 8-1 comp ratio since the 4.8 are 9-1 factory and the 5.3 are 9.5-1 factory, although the 6.0 are a much better flowing heads if your turbo is sized well (spool around 3k) then it might be worth the swap especially if you plan on pushing it to the ragged edge, but be prepared for the car to be a dog out of boost
i wonder if you could spec a cam to make the lower comp less noticeable ? then it could be a win win situation

slow67

iTrader: (2)

I would check the casting number on the crank to make sure its a 5.3L and not a 4.8L. Also Aluminum block 5.3L L33s came with flat top pistons and 243s/799s.

Chicago TDP

iTrader: (3)

Hmmm, the dude that I bought it from said it was a 5.3L engine....

The block says 4.8/5.3.

Well, the pistons do stick up over the deck, I did notice that when I was inspecting it.

I was thinking about just taking it to my local machine shop and having them punch it out and throwing some pistons in there...

But at that point, I might as well start building my 6.0...

I will check this beast out tonight...worst comes to worst, I put it in a 1985 Toyota pick-up

tripblackls1

iTrader: (11)

If you still have the stock head gaskets somewhere, take a look at them and there should be a tab at the bottom that's engraved with either 5.3 or 4.8 just so you know for sure but I would put money on it being a 4.8 which is not a bad thing if you ask me