marcus769

Next spring i am planning a big hp project but i cannot decide between going with a big cubed engine such as the SDPC 402 or stick with the 346, forge it and go w/ FI. I am by no means an expirenced mechanic, nor are there places close to me that know much about f-bodies to help. I come here for this support.

My ultimate goal is to have 500whp, but stay somewhat grounded w/ pricing. I was looking at doing a forged 402 w/ FI, but that soon went out the door when i started pricing. I think i have narrowed it down to 2 options.

1. Go with the SDPC 402 shortblock, w/ AFR 225s, nice cam etc.
or
2. Stick with the 346 LS1, forge it and run the new Hi-Flo turbo kit. (how much boost can I safely run if i were to fully forge?)

Things to keep in mind..
A. Must keep good driveability/reliablity
B. Dont plan to track the car much
C. HP goal= 500whp

I dont think I am forgetting anything.... Thanks for any/all help!

Slowhawk

iTrader: (12)

500 is real easy with a 402/FI.

We ran a LS2 402 with AFR 225's and a 232 Cam. Added the existing P1 Procharger(way too small) and hit a mind boggling 4lbs of boost -Dyno #'s were 550hp/540tq with 24 degree's of timing Probly could of run 30 degree's of timing since the motor was laughing at the lack of boost.

Ed Blown Vert

iTrader: (2)

A forged 346 with FI should do it.

WS-Sick

Yeah, 500 rwhp is definitiely easy to get with a 402 and the price should be easier on the pockets in the long run. You can also avoid some headaches associated with FI.

Avengeance

iTrader: (4)

Personally I would go the forged 346 and FI. To my knowledge the Hi-Flo kit hasnt been tested yet, havent been on the site for a couple weeks to check. As for their reputation Im sure itll be a really nice kit and drivability will be there as well.

For drivability... reliability.. and EASILY the power you want... I would go forged 346 with a D1 or even a F1 Procharger with a real nice FMIC.

bboyferal

iTrader: (9)

For 500 rwhp, go forged if you can, but you don't really have to right away. Eventually you'll need to when you turn the boost past 7-9 psi (approx. 500 rwhp), especially if you beat up the car, but there are so many users here running FI reliably to the tune of 500 or so rwhp that are running stock pistons, rods, oil pump, etc. that are testaments to what you can do on a tight budget. If you have the money right away (Don't let an FI system's price fool you, it's always more, ALWAYS! ), yeah, buy the kit, the forged bottom end, and the little miscellaneous things that creep up all at once, of course. Leave some room for a 12-bolt and a clutch in that budget, though.

abbaskhan

500 should be no prob. go with the 402 you will be happy. more cubes means a easier time making power with less boost (you can run pump gas and get even a higher number with the 402 than the 500 you want, 700rwp should be attainable easy ). get at least a 80mm turbo (if you can a 88mm) with the 402, should boost good and allow for expandability and increase in power when u want more to play with.

marcus769

wow thanks for the quick responses!

I will have the money to do it right the first time (hopefully). I just dont want to be blowing it all before i really need to.

SLOWHAWK: I think a 402 stoker is going to be too much $. To get a 402 stroker = $4,500, heads(AFR225s)/cam (232)= $3,000 (I think?) + FI= $4k-6k is too much for me.

I must keep in mind the powertrain and other things or i may be able to go with FI on top of the 402, but not both. Thanks for the good info though!

This may be a bit of a stretch, but is there any way of estimating costs for either setup? 402 vs forged 346 adding $4k-$6k for FI

longrange4u

iTrader: (2)

For F/I? Either is easy.... Hell I make more than that on a Stock LS1 with FI

marcus769

I am trying to be as safe with whichever setup I go with. By safe I mean, do not want there to be a chance of something going wrong because I didnt have the correct part somewhere else. I will spend a little more to make sure its reliable, and driveable. Your setup really looks to be working well for you. I dont remember the details of your setup (i remember reading it awhile ago), but low 11s, just kicks ***! What turbo system did you go with? I hear the turbo cars with a manual trans have some issues launching at the track... Is there a problem here? Is there any need for a turbo timer?

P.S I love your car!

30th t/a

iTrader: (51)

your thinking the same way i did...."402 or FI" . i went with a forged 347 (pistons and rods, stock crank) with a stock topend (heads, ls6 intake and stock cam) with a twin turbo setup. im shooting for 600rwhp and 10s with a full street ws6 on 93 octane.

both choices will make 500rwhp. FI will make 500 with ease. 550rwhp is pretty much it for a 402 on 93 octane and a streetable cam. the 402 will be alot easier to work on.

marcus769

thanks 10th TA, awesome input! I really dont know much about turbos, but have always wanted a car with one/two I think once you actually get your hands on them you quickly learn what you need to know, so they arent a pain in the *** as far as reliability as people say.

I really like how the 402 would I cannot afford to turbo a 402, so I think i will focus on the parts/costs involved in forging the LS1.

30th Ta, I have many questions! When you get some time, could you help me a little more!?
Have you dyno tested/ran your car at the track?
1. What kind of power numbers (dyno)?
2. What kind of track times?
3. Which turbo kit did you go with?
4. How much $ has it taken to get your engine setup?

Thanks alot!

black_z

iTrader: (4)

I would go 346 with FI. I am building a single kit for myself using 6.0 manifolds. 500 HP will be your initial goal, but im sure youll want more and more once you get used to it.

If you ever need help with anything with the car, im not afraid to get dirty. I have almost any tool at my disposal too. Im just south of Owatonna.

marcus769

Wow, this couldnt possibly work out any better!? I am also south of Owatonna.. I'm a couple miles North of Albert lea. I may be able to get us a good price on newLQ9 heads if you are interested. I have connections at a GM dealership. They would be brand new of course. It would be right at my cost. If you need some parts let me know, I can hook you up. Thanks a ton for your offer! I am sure I will have some questions! If you want some help i will offer another set of hands also. I love to learn!

black_z

iTrader: (4)

Cool, I live outside of Ellendale, and go to school in Kato so im living over here right now. I will definitely let you know about parts. I am most likely going to be running an 02+ LS6 cam, I was planning on using my stock heads with different springs, but if 6.0 heads are cheap enough I could probably swing that.

30th t/a

iTrader: (51)

well i cant answer 1 & 2 yet, hopefully in 1 1/2 months ill have it fully tuned. but i have done a ton of research. check this link out i posted. heres a guy that that has the same setup as me except he is using a big single turbo instead of twins. hes running 11.6@130 with a 2.05 60'. if he bought his 60' down to a 1.5 he would be in the mid 10 easy with that 130mph trap speed. im on the street more than the track so MPH is more important for me since i race from rolls alot of the time (hard to hook up from a stop)https://ls1tech.com/forums/forced-induction/288695-video-track.html

i bought a CAS twin turbo kit for $4300 used. they are no longer in business but theres companys making single turbos.

check your PM for the price list.

marcus769

with forged rods, pistons, and crank, how much boost can you safely run?

Avengeance

iTrader: (4)

Plenty....

With that combo you will be a couple/few HUNDRED rwhp above your goal.. and remain streetable.

Of course budget yourself for the other things mentioned.. fuel... drivetrain. With a fully forged 346 and FI + accomdating fuel mods I dont see why you wouldnt be able to get 700rwhp+++ easily.

Damn... Im going FI soon and all this forged motor talk makes me want to jump on it now instead of waiting until I have to.

mdhmi

iTrader: (1)

You shouldn't have much trouble getting 500 hp out of an LS2 without going FI.

Mark

marcus769

700hp! Holy S***!