I was refered to your forum here and found it increadibly helpfull. I am in the planning stages of building up a newly acquired low mile 5.3 long block. My goal is 400 rwhp.

Is 400 hp obtainable N/A?
I am thinking: cam, 11:1 comp, prorting, tuning + ?

OR

I have a 6.5 turbo available, I have read this turbo will work on a 5.3, has anyone here actually used one?

Any tricks or advise on building a 400 rwhp 5.3 would be great!

Thanks for your time.

Pete

 

I don't see why you can't hit 400RWHP with just the right set of heads and cam with longtube headers. What I don't understand is why our 5.3's can't hit 400HP with just cam and longtubes. I have a buddy with a cam headers only LS1 pushing 414HP. The heads and intake on a 5.3 flow better then a LS1 but why don't they show the same kind of gains the LS1 does?

 

Pete, here are some “generalities” that can be applied to Chevy SB engines:

One (1) engine horsepower per cubic inch (ci) with a normally aspirated intake (no turbo, no blower, no nitrous oxide) is obtainable with good quality control during engine building. A 5.3L displacement is about a 325 ci. Look at the Corvette 400 ci 406 HP engine rating. Oh yes…I forgot the two R words: repeatable – that is, every time your foot hits the go pedal, and reliable – after all, who wants to be turning wrenches every other day!

The engine HP is applied thru the vehicle drive train (transmission/rear end diff) to the rear wheels, but 25% to 30% of the HP is lost in the drive train…the drive train is not 100% efficient in transferring the engine HP to the drive wheels. In your case, let’s use the 25% loss figure.

You want 400 RWHP – So the engine must produce 25% more HP so: 1.25 X 400 = 500 HP required at engine. But your engine is 325 ci! Or about 325 HP (remember the two R’s – repeatable/reliable) Even using nitrous pushing a 150 HP boost (a pretty hot shot!!) is only 475 HP!

My suggestion is: if you heart is set on the 400 RWHP figure, get more ci’s…there is no substitute for cubic inches! You can push a BB to 500 HP on pump gas with the same effort as building a SB and it will be reliable too.

One last item…bring money! For the drive train (you will need a new transmission and rear end!) and green stamps (is still the commonly used phrase for tickets?).

…JJ

 

Thanks for the input so far. I guess I need to spill out some more info. The vehicle will be 80% drag and the rest for cruising and getting to the strip. The engine I have now is a 300 ci V8 dyno'd stock at 167 rwhp. I modified the engine by: porting, cam, rockers, 6 psi boost using a 6.5 turbo and now dyno's at 287 rwhp. and running 12.2 at the track (the engine is not a sbc). Now for the quest for more speed and a new project I am starting over as I did the first time with the engine I already have.
As mentioned N/A 400 rwhp sounds a bit more of a challenge than boost, and am leaning more towards the turbo myself. I guess most of my questions I can work through myself, but am really interested in input from others who also are on the quest for home made hp. I don't mean to sound cheap but I really like building, and watching the car run the strip knowing I put it all together. It just seams once I am done building and the breaking stops....it's time to start all over again.

Does anyone have a link for a home built 6.5 turbo build up on a sbc? or other wrecker/rebuildable turbos?

Does anyone have a link for a home built N/A 5.3?

Thanks again for our time and thoughts.

Pete

 

A 400rwhp 5.3L is going to require a good solid base with great compression. An awesome set of heads (high compression) and a beefy cam with long tubes, pulley, no cats (or high flows) etc.... and some prayers

No one here has done it yet so you'd be the first.

The LS1 doesn't compare to the 5.3L mod for mod. Lots of reasons why but just suffice to say it doesn't. Avg. HP for a cam and longtube LS1 is 370-400. Generally speaking most cars don't dyno much above that unless they have a really strong motor or there are other tricks involved. I see lots of crap on this board in the LS1 seciton about 440rwhp stock with just a cam dyno #s and lets just say in the real world or at least california this doesn't generally happen.

 

Pick up the new Car Craft, the did a LPE cam/heads(i think stage 1), rockers,headers, and got like 458 hp on an engine dyno, and the cam they used was a rather large cam for a driver with fuel costs, so figure you would need another 100 hp to get your 400 at the wheels, the thing that impressed me was that the cam/headers, mad an extra 100 hp over stock, bringing it up to like 413, and the heads only made an extra 45 approx. horse. We all know that headers aren't worth as much on our trucks, so that little cam is worth it's weight in gold compared to a pricey set of LPE heads. I'm thinking of slapping in a decent cam, a set of patriot heads, and a little spray for the occasional oomph i might want to smack a lightning.

 

Thanks again for the answers so far.

F8L Z71 do you have a website or build up thread of your modifications?

As you can see by the 290 rwhp right now pushing us 12.2 in the 1/4 this set up is not being built to go into a C/K truck. We are looking to run solid to mid to low 11 sec and estimate 400 hp is required for this task. Also as time goes on no doubt we will continue to try and go faster. With spray not being an option for us, n/a at best will give me close to what we want with no room to go faster.

As I have been reading, stock bottem end 5.3, 6.0L heads, free flowing intake and exhaust, cam, porting, along with a good supply of fuel and ecm tunning we will be set. Or is there something I missed?

What cam do you run F8L Z71 or other turbo 5.3 owners? What supplier is preferred?
Do you guys still run the stock 5.3 intake with a turbo set up?

Thanks again.

Pete

 

I don't have a site yet although I should at least create a page. They are so simple anyhow LOL

N/A I ran a 226/.535/112 cam with AS&M long tubes and no cats. Made good power and got me a best of 14.29@97mph at a 4900lb raceweight. My dyno was only 304rwhp due to ZERO tuning before hand. I picked up 2+mph in the 1/4 after tuning so I should have been in the 320-330range according to traps vs weight. This was on stock heads and no pulley.

On teh turbo setup I am running a 226/220 .591/.554 116 and stock manifolds.

I have always used the stock intake manifold. I didn't wanna mess with the LS1 and screw with my smogability.

I think you can reach your goal if you do everything to the hilt and dont have all the power robbing accesories that a standard daily driver has.

 

Hey PBJT, look at my signature for some ideas on the 5.3/4.8 block. It can be bored out very easily to the same size as the stock LS1 and maintain > 0.150" of cylinder thickness. I have not dynoed the motor yet but I can tell you this: it has SICK torque and acceleration! Lights up the 31" BFG's at will from a standstill, even up here at 5000ft. Not sure but would estimate the power near 350 rwhp or so. If we had gone crazy with some better heads and cam 400+ would easily be there.
Boring out the block gives you access to a HUGE amount of LS1 internal parts and the security of having an iron block if you do decide to get heavy with the turbo. Only difference in 5.3/5.7 is aluminum and bore ( 3.78" to 3.898" ).
Last, the "bring your pocketbook" is true. While the LS1 parts are becoming much more available they are still quite expensive. Conservative guess is $500 machine shop, $2000 for lower end, $300 for ARP bolts, $1800 for stageI heads/cam.
Lots of options and cheap 5.3 motors out there! Good luck, let us know how things are going.

 

buddies running 420rwhp and 500 trq on z06 cam vig 2700 stall ASM headers heads done by elliot headwork with a 2.0 valve size i believe and an air intake with a 100 shot very reliable last truck he had (before wreck no it was not racing) ran two or so bottles a week for almost six months with similar setup hope this helps