terry318

I am new to the site and trying this out. I am in the process of building a 408 for my a 87 SWB C10.I have a 5.3 in it now all stock and want to build something with some power. I have some thoughts for the build starting off but any advice or input would be appreciated. I plan on buying a rotating 408 assembly for TSP seem to be reasonable plus they talk and try to help me get the parts I need for a strong engine.Plan on using LS3 heads and the L96 intake and that's all I have for now.Plan on getting TSP to help me with other performance I need such as cam,push rods,oil pump,water pump,etc.If anyone have build a 408 recently please give me some input

HCI2000SS

iTrader: (2)

TSP and TMS have great prices and service for this kind of stuff. I went with TMS for my 370 and am very happy

ragtopz28

iTrader: (57)

After a lot of research, I abandoned my 408 build. Stay stock stroke for a DD/longevity. The LS cylinder walls are to short IMHO for a 4" stoke and the piston is pulled out the bottom at BDC (not good). There are some major engine builders that don't even offer a 408 for that reason. I'm sure there are plenty of stout 408 out there and are doing fine. The physics don't make sense to me to risk it (unless you go tall block). Just my .02...Let the flaming begin.

terry318

First time hearing such thing about the stroke for 408.My build will be for a street car and longevite will be a must.So what kind of power could I make with the 370 but I still would like to go 408 but dnot want any issue down the road.

HCI2000SS

iTrader: (2)

Great power can be made on the 370 as well, you just need enough compression and a good HCI. 500 rwhp can be done with a good top end

terry318

So what makes a lq4 a 370 and what type of top end that will help me accomplish this goal of 500 rwhp.

HCI2000SS

iTrader: (2)

What makes the LQ4 a 370 is a slight bore. The stroke is still stock. Any good aftermarket casting (TFS, AI, Mast, etc) with a Fast intake and good size cam will get you there. But of course your exhaust has to flow great as well

ragtopz28

iTrader: (57)

Edit...Ha ^^ beat me to it....
.030 over bore and stock crank/stroke make a 370" Some BA cathedral heads and matching cam should get you close to 500whp.

Tuskyz28

I'm thinking the 5.3 sleeve is even longer than the LQ4 sleeve. I'm go have to dig that up. I got it wrote down somewhere.
What is your horsepower goal?
Total budget for complete motor?
Me personally would build a iron 5.3 to a 5.7 or like the other guys mentioned the 370ci shortblock..
I would avoid the fast intakes due to the cost and go with a trailblazer SS intake. They sell for 150 bucks average. Peak speed shop ports them nicely. It'll accept a 90mm throttle body no problem. Then for the heads I would look into a "as cast 220 tfs" head with guides to accept the factory rocker arms with the trunion upgrade.
I'm not sure what rear gear and stall converter you are running now so it's hard to recommend a camshaft. Hard to beat a tried and true 224 duration cam with a factory stroke engine tho. Great power down low and it'll hang on up to as well.

terry318

My HP goal is 450ish and my budge is 5k-6k and I plan on running 373 postive rear end with the least stall as possibe depending what I need to make everything co-mingle together.But the help and all the input about the 370 might be the way I go because I would wether build it right once then twice.

Tuskyz28

450 at the crank or at the wheels ?

terry318

450 to wheels and I probably will be using the 4180 trans as well

HCI2000SS

iTrader: (2)

450 rwhp through the 4l80 will to be a little harder but again very doable with info said above

terry318

Have anyone ordered and LS product from Dream Stell Garage.They sell old muscle car parts and now they are getting into selling LS parts for low prices so have me worried eventhough everything seem to be legit.

cookseyb

Don't forget Scoggin- Dickey Chevrolet. They have been a great help to me building my 6.0. They helped size my cam etc. Nice Folks...

Aaron at SDPC

We can definitely help get you fixed up with the right parts to reach your goals. Let us know if there is anything we can help with.

KCS

iTrader: (20)

There are a lot of reliable 4" stroke combos out there. It's not necessarily how much of the skirt is pulled below the cylinder at BDC, more like which part of the skirt. As long as the major diameter doesn't come out and the bottom of the cylinders are deburred, it will last a long time.

I've got a 4.250" crank in an iron 6.0L block and at BDC, the piston doesn't rock any more than a 4" stroke piston. It's a custom piston with thin rings and a short compression height, but it makes this kind of combo possible.

I've seen the same. I measured a bunch of blocks and recorded the casting numbers and cylinder length. The aluminum 5.3L (12571048) was 5.560" long, the iron 5.3L (12576177) was 5.540", and my iron 6.0L (12551864) was 5.530" long. The LS2, LS1, and LS3 were shorter.