Suburbazine

83 octane? Good heavens, what 20th century part of the world are you living in?

If you really meant 83 octane, no that won't work. If you meant 93 octane, that will run just fine.

I went with forged rods on mine for extra insurance, I don't think you need them but if any boost or nitrous is in your future I would highly recommend them.

iamkeniff

iTrader: (16)

Pistons can be had for cheaper
Do coated cam bearings imho
You need rod bolts main bolts head bolts. Arp is the only way to go.
Get away from the 706 heads they are problems
Leave the 102mm alone its worthless other than for looks.
Why do a flex a lite fan kit just do an 05+ radiator dual fan swap.
Also the fuel rails are pointless on an oem intake.

fastgmc53

iTrader: (33)

shame were not closer.. I have a 5.3 bored for 3.903 forged pistons that is still just sitting in the bag... I had all work done then decided to go aluminum block I was headed the iron ls1 direction

cousblake11

The intake is 26mm bigger than stock how would that not help the air flow? the fuel rail was for that intake, I wouldnt put it on a stock intake..whats wrong with the 706 heads? they work really good for being stock, where would I get cheaper pistons at? that was Ebay pricing, I didnt even think about that fan swap, where would i get those at?

69Camaro427

The LSx intake will run better than a nbs above 4000rpms and will run the same or slightly worse down low. You would loose some low end tq with it, and the $900 manifold, $3-500 TB and $200 fuel rails not worth the 15-20hp it brings. Plus a lot of people have a hard time tuning the LSx intake with a good size cam in it. Bigger is not necessarily better especially with small cube motors.

The 706 heads are more prone to cracking than 862, 243, and 799. Your 706 heads are 61.15 cc! The 243 and 799 are 64cc These also have larger valves intake 2", exhaust 1.55" verses your 706 intake 1.89" exhaust 1.55".
The 243 and 799 heads intake runners are 10cc larger and exhaust are 5cc

Engine Size and Compression Calculator
use this to calculate your compression. If you are staying N/A just get some good shape used ls1 pistons, they are flat tops, so with ls1 pistons NON milled 706 61.15cc with stock 0.053-0.051 gasket height you will be at 10.9 to 11:1 compression, which is fine for 93 octane. Especially if you don't live in brutal heat conditions.

A 6.0 probably averages from $800-1200 so if you can get all your machine work and pistons for under a grand then you are only giving up 0.3L.

69Camaro427

Call a local machine shop and let us know the price for machine work and assembly of the short block is!

cousblake11

I was gonna get the 706's milled to 64cc and bigger valves, I can get the block bored and ready for me to put together between $400-$600, id put it together and put it in the truck myself. Would it be cheaper to just get 243's? if so id prob just do that. but I still think that with the iron 5.7 id have heads that flow round 64cc's, XR265HR, LS6 springs, and 7.4" pushrods. so now where would the best piston's and rod's be found at?

1FastBrick

iTrader: (17)

You can't mill up to 64cc on a 706 head there around 61 cc from the factory. if you mill you lose CC's in the compression chamber.

Some of the 706 heads were known to crack at the casting seam in the head bolt area. That doesn't make them all bad. They need to be checked before performing any work on them.

69Camaro427

$400-600! Yea I would do that if the motor is out and not on a time crunch project. It is expensive to change valve size and port heads! It is cheap to mill heads however. Anything over a 5.3L should at least run 243/799 or larger heads. In general the smaller the intake runners and valve size the more low end tq your motor will make due to a high velocity of air, but less top end hp b/c the motor starts suffocating for air. The larger the runners and valves the more flow/volume which will make more top end hp providing the motor with plenty of air, but the air velocity will be lower causing some loss in low end tq.

With that said if you run you stock 706 heads you will make more lowend/ midrange power, but ported heads will give you more top end. I think a set of 243 heads would be perfect. They will give you more top end, but wont hurt the bottom end.
243/799 64cc
706/862 61cc

Compression difference with 3.905 flat tops, stock NON milled heads, and stock height gaskets.
10.55:1
10.95:1
Roughly for every 0.007" milled 1cc is removed from the camber so if 0.030" was removed 4cc will be removed. 243/799 with 0.03" milled will flow more roughly 15-20 more rwhp and will make 11.1:1 compression.

If you leave the heads non milled than a 7.4 push rod should work, it would be wise to get a pushrod length checker and check, especially if you mill the heads

If you are staying n/a you don't need forged. Plenty of stock parts rolling to 300K+ miles. If you plan on nos/boost in the future I would get forged pistons and rods with arp studs and bolts. The stock crank is good to 800-1000 hp. Again you don't have to by the best forged pistons/rods if you are only making 600-800hp lets say. The higher the power/boost/rpms the better quality of parts you need.

cousblake11

Okay so ya'll help me with the list then. tell me if this sounds bout right

3.905 LS1 pistons (forged flat top -2cc?), Moly Rings
Hardened rods 6.098
stock crank (3.622 stroke)
Stock heads? 243 heads? stock or ported?
Xr265HR
LS6 valve springs
Pushrods?
Stock intake? or aftermarket?
Fuel injector? what size? stock or bigger?

also I was meaning 87 octane the lowest, I know that's not the best gas to use but I was just wondering what the lowest grade id be ok running, ill prob use the highest on the pump but just to know, how low should I go?

also since I already have the tranny figured out (B&M 4l60E), what should I do about the transfer case? what kind would it be? and should I get it rebuilt or does an aftermarket brand make a better one? never messed with those before, what would the average price be for either a rebuild? or a new one?

any help would be appreciated, Thank ya!