kp

iTrader: (34)

I went for the 347 simply because it was the cheapest/easiest. Didnt want the extra 100lbs of an iron block or fool around with the LS2 covers. Also the previous 347 ran just fine with no problems after a year of beating on it and I saw no need for more cubes.

With a D1 you will be limited by the amount of air it can flow period, doesnt matter if its a solid roller c5r 427 or a Z06 cammed 346 its only going to move so much air and make so much power. To me its a huge waste to build a killer 408 with big heads and big cam and hang a D1 on it to make 700rwhp @ 7psi when a small cammed 346 will make the same power @ 14psi spinning the blower the same rpm for less money. Even though the 408 will make more power off boost the 346 isnt all that bad. Now put an F1R on that 408 and get it up to 15-20psi and then your money is well spent

My car isnt really a good yardstick to measure anything by, its pretty much a race car and I try to use all the power it makes the best I can to get from point A to B.

Jimmy P

iTrader: (177)

I had a built 346 that I was supposed to be get procharged. During the removal of the heads, the guy doing the install saw some issues with the sleeves. I decided to put a 402 in there, and get rid of the 346. I know the 346 would of been fine if it was in good shape, but since it had to be taken to a machine shop to get fixed, might as well upgrade to something a lil better. If I max out the D1SC with the 402, I can always just put a nice twin turbo setup on it next year(if I have money to afford it). I should have some numbers with the D1SC 402 within a few weeks.

CHRISPY

I think he was running 16-17#'s boost on the 147mph pass.

Chicago Crew UnderBoss

iTrader: (1)

WELL SAID and I agree 100% and another reason for going with the forged 346/7 with a D1SC is as follows:

The 346 D1SC set-ups have way less issues with belt slippage, pulley alignment, and our much more low maintenance, and of course a stock cubed LSX motor that is BLOWN, makes crazy power more than you can ever use on the street. You don't need a big displacement LSX motor that is BLOWN to make huge power and run incredbile ets and mph. KP is a living example of that runing 9.44 ets at over 144mph with a STOCK freaking LS6 cam for crying out loud and I don't see any big cubed D1SC cars running any faster and certainly not more reliable than KPs set-up!

The stock cubed forged D1SC setup is the most simple, reliable D1SC set-up you can have that is more than enuff to make STUPID POWER and is the way to go in my opinion (and of course its also the most economical way to go) and will have the smallest amount of issues vs. it stroked and bored competiton!!

SVC707

iTrader: (33)

another reason why i chose the 408 is i know im not even pushing the motor that hard with what i doing. its not a drag car or a track car just ***** and giggles. and like others have said i know i can always push it later on down the road.

TrakDay

iTrader: (7)

I prefer the bigger bottom half. I have a forged 408 with ET240cc heads on the way for my F1C Procharger setup going into the GTO. My goal is to make as much power as possible while not putting too much pressure on the motor itself. Thats why I went with anything big to keep the air moving which in turn will hopefully produce in excess of 850rwhp without any problems.

BigBronco

iTrader: (2)

Get the biggest motor possible.

BIG BAD BLACKSS

iTrader: (4)

Humm everyone keeps saying get a BIG motor, but the fast guys have lil motors lol.

So if i go say 402/8 with the D1 i might make a lil more power down low and see the same HP #s as i would with say a 346 or 370? I just dont wanna put too many cubes in it for the D1. I do plan on going up to the F1 next year possibly. Maybe ill look into a 40X?

So again, i wont loose anything going to a 40X vs something in the mid 300s? With the D1, im sure the F1 will love a big motor.

BIG BAD BLACKSS

iTrader: (4)

Oh and how would the 6.0 heads like a 402 with boost? Not enough head, or will it hold me for a while till i can get some good heads?

ty_ty13

iTrader: (42)

with less restriction you will see more power because your inlet air temperatures wont be as high and you could run a lower octane gas or run race gas still and turn the timing up and make more power....

if you can afford it a bigger motor will help it just depends what you want to do... if its a street car a bigger motor will help keep the IAT's down and let you make more power with, say a 93/91 octane gas... is that worth it to you? i dont know but this is what i decided to do.

markp03

iTrader: (4)

if you are using a d1 go with 346...if you want more power get a f1 and a 408... i don't think it is worth putting a d1 on a 408.

BIG BAD BLACKSS

iTrader: (4)

My goal is low ETs, and if i have to lower the boost for street driving thats fine. First and foremost its gonn be a dragstrip car. Ill just be one of those crazy people driving the race car on the street occasionally.

Drewstein

If I had pistons that could take it, I would have 750rwhp on 91 octane. The 346 can make monster power if the tools are there to let it.

Also I have seen nothing but problems with blown 400+ cube motors. They toss belts from so much low end torque.

Forced370GTO

my philosophy is; with a larger motor, the same amount of power can be made running much less boost. instead of forcing 18psi on a 346, im going to run about 11-12 psi on a 403 from my f1-r spinning in its efficiency range rather then using a d1sc to the point where it is loseing efficiency at an exponential rate. at 12 psi with et 240 heads and a very well flowing exhaust and intercooler, 800rwhp should be easily in reach, meanwhile im not running crazy amounts of boost and my supercharger isnt at its redline 24/7. all of this will produce a system capable of withstanding much more abuse then a 346 d1sc combination which obviously needs much more boost to compete with a larger motor.

if we are talking about torque i dont need to say much, bottom line is the bigger motor will kick you in the *** on the low end.. just my $.02

WAHUSKER

iTrader: (4)

Besides the basic rule: Cubic inches or cubic dollars, this is why I went with a 402.

A 402 = no cyl sleeves. A 402 = more torque. A 402 = less boost to get the same power. Less boost = slower s/c head rpm which makes it all last longer. Once I get my D series on (this week I hope) & running at 12 psi, I'll see how close I can get my 4000lb land yacht to the 10.0 barrier. But I do NOT want to run 9s, cuz I am NOT putting a cage into my car. You sound like you're going to push it....

And yes, 6L heads seem to work fine. I bought a set off eBay & had them ported & put bigger valves in.

JASON11WS6

iTrader: (7)

I'm in the same boat here. Just picked up a D1SC and want to build a bottem end to hold it. I was serously considering a bigger motor build up and maybe even switching over to an F1 down the road. But, after seeing hardcore numbers from the 346 cars I think I will be happy with a forged 346 and about 10-15#s. That should propel a tank into the 9s which is all that you really need for a street car. Anything after that is pretty silly, even if you can make it some what reliable. If i can get between 600-700 RWHP like that I'll be happy and who knows maybe the TNT kit can make it's way back on the car if I feel like playing with explosives. If I had more money and no baby on the way, I might try to just man up and get a 402/L92 set up but I can't beat that 346 bang for the buck.

JASON11WS6

iTrader: (7)

I do have some questions though. What are the pulley sizes to run what amount of boost? I am pretty sure I have the stock pulley on their now and was wondering what sizes they offer and stuff.

EPP

iTrader: (22)

With a forged bottom end on the 346 and the most amount of boost, go with a 3.4" pulley which is typically the smallest one you will find available. Keep an eye on the inlet air temperatures, and I don't advise running this much boost if you are using the smaller 3.5" twin hi flow intercoolers. You will also need to completely revise the fuel system for rwhp higher than 600 rwhp.
Boost and pulley size depend on many variables. Headers, exhaust, cam, heads, cubic inch, max rpm, elevation and probably more than I'm not thinking of all play a part in how much boost the blower/engine combination is going to produce. Bob

Pro Stock John

iTrader: (34)

What are the big cube/D1SC guys running for trap speeds at the track?

I find that point about bigger cube setups throwing belts very interesting.

ty_ty13

iTrader: (42)

as soon as it gets warm again ill have my stock headed 408, gmpp, FMIC, d1sc 3.4, th350, 28'' DR, 12 bolt 4.10 out at the track...

i know it wont 60' very well becuase of hte lack of suspension - there is none... but i do have som nice chassis pieces- BMR Xtreme TA and sway bar, lca, sfc, and a 6pnt cage....

i hope for sub 7's my first time out to the local 8th track.... then id like it to be under 6.51 by the begining of summer.... i'd be happy with a 9.9x "street" car for a year or so..