C5Natie

Well, after my LS3 let go a month and a half ago, I decided to build a somewhat budget friendly big boost 5.3.
I'll be feeding it boost with my Vortech V7 Ysi with an A&A 8rib direct drive setup. I'll also be running a 2.7 pulley and expecting to see 25psi or so, E85 fuel.
The shortblock and heads are ready to go. Im currently porting an intake for it while I wait for my friends shop to have new lifts installed so we can get going on putting it together. I'll post pics in the next days to come. Only thing new is the motor. The blower setup, fuel system and exhaust setup are already on the car.

Shortblock
LM7 iron block
Wiseco 3.8 forged pistons w/upgraded wrist pins
Callies Compstar H beams
ARP 2000 everything, studs
Scat forged crank
BTR custom cam
Top End
Newer (better casting) 706 5.3L cathedral port heads rebuilt, Manley springs
(Bowl ported and with 2in intake valves installed, all valves stainless steel)
LS9 head gaskets
Pro Comp LS2 96mm Qualifier intake (I know I know, got it super cheap)
Ported runners and cleaned up casting flaws. Opened up for 102mm tb
102mm Nick Williams TB
Exhaust
1 7/8 Stainless Works full length headers
Custom Carven Exhaust full 3in
Fuel
E85
ID1300cc injectors
Custom fuel system
Power Adder
Vortech V7 Ysi w/2.7 pulley
A&A Corvette direct drive bracket system

Not sure how much HP to expect so we'll see
(Added pics on page 2)

jackthelad

With that amount of boost, I trust you are not running a high CR.

C5Natie

Around 9.5:1 which is more than safe on e85

Evil-Twin

better beef up the suspension, that iron block will add a lot of weight to a suspension designed with no design room for more weight.

Vetteman Jack

Looking forward to seeing more on the build. Best of luck getting it all back together.

C5Natie

I have coilovers and will be installing stiffer springs but to be honest, I've been in other iron block c5 and c6's and it's not as big of a difference as people make it out to seem. The motors are so close to center on these cars that you don't feel the extra weight as if it were over the nose.

C5Natie

Thanks man. I'll be posting pics and hopefully we'll have the car back together within the next couple weeks

Rob 02

Just curious. What is the advantage of the smaller displacement and iron?
I'm assuming it is for super high revs and added strength.

I like the torque and weight savings of, perhaps a stroked LS3.

C5Natie

Well you mentioned two, revs and strength. Also cost is a factor for some as a brand new GM 5.3 block can be had for $300, complete used motors for $500. With a big blower or turbos you can make the power come on fast and early. Either way you'll make more power than you can ever really use on the street.

Evil-Twin

Many disadvantages to iron... weight, heat dissipation.. the LSX aluminum alloy is almost bullet proof and can see 400K if properly maintained. You wont see too many 10 + CR iron blocks getting any where near that.

The LSX was built with project management to insure maintaining a tight budget and an on time delivery, there is no over kill or consideration to increase any of the parameters including adding weight to the front end. bearings and springs are not designed for the weight of an Iron block. Will it immediately be an issue? No... But it is a nail in the coffin.

Rob 02

Plus you could have more than 75 more cubic inches with the lighter block. That may eliminate the need for power adders and super high revs.

v8srfun

There is always 2 sides of the coin. The added weight is not going to hurt wheel bearings and shocks/springs. Granted it will not handle well but there will not be damage either. Boost is fun and if a iron block makes it financially feasible go for it.

StayinStock

i say boost her to the moon, awesome setup, should be tons of fun and the best part... when it lets go, call up the local pick a part and grab you another shortblock, back on the road in less than a week. Considered this option for mine but decided to go Iron 6.0 instead... lil more money but same concept. Im doing it with a V3, very curious to see your results and numbers!

1SLO2OH

Sounds like an awesome build. I'll be watching for updates! When making a lot of power, the lower torque and more revs of the 5.3 will help the power come in smoother and more linear and make more on the top end which does wonders for traction. Which for a street car is a good thing. I could see more low end and overall torque being beneficial on a prepped track with slicks, but it all depends on what you want to use the car for.

Roddy13

Cool. I know those 5.3's and 4.8's can be picked up from wreckers from super cheap. $300 for the 4.8's and $500 for the 5.3's are some common figures.

Interested to see how it turns out.

tbrent

Cool. When you do a different motor like this are you using a wiring harness that's original to the 5.3?

jackthelad

LS1/6/7 blocks around 110 lbs

LSX or 6.0/5.3 iron blocks around 220 lbs.

You will ride a little lower at the front without suspension work, and of course the blower, plumbing, etc., will increase weight even more. Stiffening the front suspension will have the side effect of increasing "push". Moving the battery to the back of the trunk area (i.e. behind the rear axle line) would help rebalance the car some.

Rob 02

A stiffer front spring wont feel stiffer with more weight. The stock spring will feel softer.
I think the added weight would reduce under-steer.

jackthelad

Stiffer springs mean more roll stiffness at the front which will cause a little more understeer. And another 100+ lbs. forward of the current C of G will add to that, hence my comment about moving the battery to the rear.

Nothing that can't be balanced out though. A bit more tire on the front would do it - Ferrari did exactly that to get rid of some of the understeer on it's "hot" version of the 488. Not that the 488 isn't "hot" to begin with.....

C5Natie

Thanks man. The bottom end on this one is fully forged so I hope it doesnt let go too soon. Lol