startat2

iTrader: (2)

So I'm currently at a stand still in my build. I have my motor ripped apart and new heads that arrived today. I can't decide if I should build a forged 350 with nitrous or a cast 383. The parts come in at close to the same, with the 383 being just a bit more expensive.

This car is a 91 camaro v6, that Im swapping to a v8. I always tell my self its a new "race car" but the reality is that I drive it on the street like a grand ma, get on it every now and then, and make it to the track 1-3 times a year since I work weekends and nights.

So far I'm leaning towards the forged 350 but had a few questions. How much spray can I really go? I was thinking a 150-200 shot, but want to know what the top end capabilities would be provided everything is in tune. Also, with a build being similar, how much power does a 383 pick up over a 350? I havn't seen a true apples to apples comparison, but it seems like people who want cheap power (no offense) end up making a little less with a 383 than they do with a hot 350, and that a nice 383 is only making about 40/60 hp/tq difference over a 350.

Between the two, which can I make more power with and which will be the most cost effective per hp?

Any input is appreciated!

five7kid

iTrader: (14)

Assuming both are expected to be driven on the street with reasonable manners, a forged 350 built for a 200 shot of nitrous will make about 150-170 more HP than a cast NA 383.

On the track, the 350 will be a bunch quicker than the 383, assuming you spray at the hit.

startat2

iTrader: (2)

Thats what i figured. Would the best of both worlds be a forged 383, or will the HP benefits be marginal? AKA will a take more juice, or just give me the same hp advantage that a base 383 has over a base 350?

Orr89RocZ

iTrader: (20)

Given the same heads and similar cam, the 350 (on motor alone) can just about match the 383 in hp, maybe a few short but will not make the torque. Of the dyno's i've seen on 355 LT1's vs 383 LT1's with similar heads/cam packages, the 383 made about same hp, sometimes 10-15hp more than the hot 355, but the 383 peaked earlier rpm wise, and made a bunch more torque which is helpful at the track and street.

Now a 383 has capability of making more hp if you cam up alittle more and give it better heads, but still, the 350-355 wont be too far behind in HP, it just has to rev alot higher to get there. Lower revs are better on parts so its one advantage to building a 383.

A 355 peaking at 6500 rpm wont make the power a 383 will at 6500 rpm, but the 383 needs more head/cam/intake flow to pull 6500 rpm than the 355. Larger the cubes, the more air flow it needs to pull rpms.

Cranks are the same price, pistons/rods are the same price, so the only difference in building a forged 383 is the extra block clearancing which aint much. I think the torque benefit is well worth it and i'd spend abit more money and go 383 forged with nitrous.

That way you will have the best of both worlds. Power and torque.

But as is, a properly built forged 350 with a 200 shot can be a mid 10 second car. You can get mid high 11's in a 355 and 200 shot will easily push low mid 10's. Just need to wind the motor up. A n/a cast 383 cant do that.

startat2

iTrader: (2)

How high do you think it should wind up? Also is 200hp the time when I need to be looking at a nitrous specific cam? I was really leaning towards the 350 unless the crank I have is no good, then its 383 for sure. Mainly for the fact I already have my heads in and really dont think they are enough for a 383. (vortech)

Orr89RocZ

iTrader: (20)

vortecs are abit better for a 350 but better heads are out there for higher rpms. For a 350 with forged internals I'd cam it for a 6300-ish rpm peak and let it go to 6500+ but only if the heads are there

200 hp can use a typical n/a cam but you can get a cam thats more suited for nitrous and still be ok on motor... its a mild tradeoff in power either way but not much to be worried about.

zraffz

Why can't you run hypereutectic coated pistons, the cheaper 5140? forged rods, and a cast crank? I've seen the local shop run hypereutectic pistons and the pink powdered rod in small blocks and turn close to 500 horse.
The machine work for the stroker crank is pretty cheap, a descent cast bottom end can be pieced together for like $800 and support mid 11's in a full weight camaro.

From what I've read the main difference between a 350 and 383 was already stated. 10-20 horses, 25-40 ft lbs and the biggest difference is where the peak power is made. Higher revs are useless on the street and will reduce low-end power. I'd build the 383.

startat2

iTrader: (2)

I guess what is holding me back from the 383 is mainly my heads and the crank. Like I said I drive like a grammy Hypereutectic is an option, but I've heard they dont fare as well with nitrous use. Would they still handle a 200 shot? I'm not trying to go cheap, but I also don't want to replace what dosn't have to be (AKA crank)

Orr89RocZ

iTrader: (20)

They can handle it if the tune is spot on. Any miss-hap in the tune causing detonation can hurt those pistons in a hurry. But you can hurt a forged piston as well but they tend to be abit more forgiving

zraffz

I wouldn't suggest them in a high nitrous application. For a NA motor they are good for just about anything a street-built 383 can throw at them.

Your heads won't hurt a 383, it will still perform just as well as a 350 on the top end but you will have more torque. If you drive like a grandma on the road but want to throw down fast times than a 355 with the 200 shot is a better bet.

startat2

iTrader: (2)

Ok, I think census says forged 355! Thanks for the help guys :wave: