jb7241986

iTrader: (4)

let me know thinkin of running a setup with an iron 6.0. what kind of numbers with set of 5.3 heads a decent streetable cam with a nice lopey idle and an ls6 intake? would 243 heads be better or make less power? thanks fellas

$O$OE

iTrader: (14)

The iron blocks are about 60lbs heavier,I would pick up some L92s instead of the 5.3s, but then you will need to run a L92/LS3 manifold with those heads.

bluebird00

iTrader: (9)

i think it like 40lbs difference. my bro is running a 6.0 iron block with a mild cam he is pushing 380 rwhp.

Rob's 02 SS

iTrader: (31)

I thought a 6.0 iron was 80

vicouSS00

iTrader: (47)

mine made 512/502 with the TEA 5.3's off my ls1 and a fast 92/92 through a cutout

1slo_ls1

i heard its not worth the swap cuz its heavier and their is not much of a hp difference

Cliff

iTrader: (19)

There's no need to run a iron block on a N/A motor with heads a cam, it's just 80 lbs of extra weight. 243 heads have slightly bigger combustion chambers and have better flow numbers when comparing 5.3 heads if they are ported the same. Hope this helps.

SUTTERERMAN85

iTrader: (42)

about 80lbs

Tootall

iTrader: (78)

58lbs more
run the 243's, but have them milled 30, and run your LS6 intake . . . higher compression

or get a set of L92s , and the L76 intake, run a mild cam, and have better numbers/street performance

dry_kill

iTrader: (12)

gotta remember too, with the 06 6.0s i believe the rods are a little beefier, letting you spin the engine a little higher

NemeSS

iTrader: (127)

a lq4 with milled stock 317 heads will get around 10-10.2:1 scr depending on gasket used. the heads flow just as well as 243, a vj and backcut to the valves. equipped with a lpe gt11 cam, it will make for very aggressive acceleration engine on wot,when driving around normal, u would think its the stock cam.

Jip99z

iTrader: (1)

The iron block is better for modding vs the alum block, less flex throughout the block and able to withstand higher pressures, etc. If your only doing a mild cam and heads, I would try and stay with the alum block to save the 80 lbs but if you want to add dope or anything else down the road then i'd grab a 6.0 block.

Reject

iTrader: (24)

MM makes over 1000hp on his alum ls2. not much flexing. iron is just cheaper to mod

thats_10kid

iTrader: (15)

i got a 6.0 iron block with MS4 and p/p 243s and i put down 431/404

MSUGTP

Have there been any problems with running aluminum heads on an iron block? I didn't know if there would be, never heard of any complaints of it. Just thought it would be something to consider with different expansion properties of the different materials.

00fastta

Nope look at the lq4s and lq9 on all or most trucks.

Dirty 30

iTrader: (96)

I did 435/425 with an LQ4, MS3 cam, and LPE mild ported 853 heads in my 30th back in '05.

Dirty 30

iTrader: (96)

Some early LQ4's had iron heads.

69_YENKO

iTrader: (16)

So the consensus is that its only 80#s more? . Im about to drop a 408ci in mine and was told it was closer to 100# more, maybe the beefer rotating assembly is adding to the weight?

CarsandWomen

iTrader: (19)

yeah the longer stroke adds iron to the crank. The books ive read say the block is 80 lbs heavier

on the flexing part, The LS1's were designed around aluminum. they use iron in the trucks because weight is a non issue and its cheaper and tougher. The original design of the motor was for aluminum so all flex and associated problems were accounted for. Adding power can change the equation yes but still.......

im going NA aluminum block and 5.3 heads, L92's if i can find em but that intake kinda sucks compared to the ls6