383 Bottom end strength

[WFish]

How many horsepower can a stock 383 bottom end handle? My dad wants to know how much nitrous he can use on his 383. It has stock shot peened rods, forged crank, ARP main cap studs, stock main caps, ARP rod bolts, and Clevite bearings.

[hotrod7043]

probably alot till it blows up, nitruos is a easy way to sadness.

[ehostler]

I would not go with more than a 125 shot. Anything more, without properly building the engine, will result in a catastrophic failure.

[WFish]

What exactly do you mean by properly building the engine? Don't get me wrong. I'm happy with 125 hp, but I just wonder what it takes to go further.

Thanks!!

[Tarrbabe]

I am no expert but I felt I wanted to put my 2 cents in. Any engine needs to be built to withstand the rigors that you intend to put it through. Don't expect a well built 383 to hold up to large amounts of anything. They are tough as nails, but can be pushed past what the design limit is. I have heard of 383's putting out over 600 hp but you must know that the engine will require a lot of maintaince and more often rebuilds. It would be possible to get 1000 hp out of one for about 2 seconds. But the extreems placed on the small cubes would take a toll quickly. I always thought that nitrous should run a reduced cp due to the increased pressures but everything I have read from people posting is not so. Large amounts of nitrous and gas is the same as a blower producing a lot of boost. Controling the combustion will become the most of importance.
What I have read, is that with cast pistons, stock rods and crank you should stay 125 or less. The larger shots will require a lot more strength in the bottom end.

Just thinking out loud.

[b-1ken]

I build all of my B-1 engines out of 400 blocks which are essentially the same as a 383. I install steel main caps and cement the water jacket about 2/3 of the way up. Other than that the blocks are stock. The 499's make 820+ HP and the 511 makes about 850 HP. If you do spray that 383, and it hasn't been properly prepped, it probably will give up. Whatever you do, make sure it has enough fuel and be conservative with the timing. I had a student who installed a 125 HP kit on a SB Chev. 400. He used to take that thing out to the track and hot lap it. He also drove it on the street and regularly whipped on it and never had trouble with it. He did say, however, that he fattened it up a bit to stay on the safe side.

[440Philbert]

At least 1 guy asked about what pistons you're running?

Nitrous is a higher percentage of oxygen relative to the air we breath. Given a proper fuel ratio is maintained, catastrophic failure can be avoided easily.

Would you run cast pistons with a 14:1 roller cam motor? I hope not, fortunately the uneducated get lucky since valve-to-piston clearance and achieving that compression won't allow that combo to happen w/o changing pistons.

The general consensus is as mentioned....

stock/cast pistons = 75-125 hp NOS doses

above that you'll need to dial back ignition timing, spark plug heat range and possibly compression with every 50 hp increment thereafter.

[dirty dan]

125 is not the limit on a 383 with cast pistons.
150 is a safe amount.
If you go up to a 175 you will start to blow head gaskets.
Also you will need to adjust your timeing to acomadate extra fuel.
At 150 HP you should back off the timeing 2 degrees.
Beyond that the timeing should be retarded 4 degrees for every 100 HP.
If you use an adjustable system be conservative when youselect your set up.
You don't need the bigest system available if you are only useing
the minimume shot on your engine.
As mentioned befor keep the fule mixture on the fat side.
There are many differant manufactures of system .
Both adjustable and pre set.
the choice is yours to make.
I have had great results and no complaints from comp-u-car's
150 none adjustable set up.
The price is reasonable and the quality is good.

[WFish]

The 383 has forged pistons. I was just wondering about the rods and crank strength. I don't plan on using some ridiculous amount of boost or anything, but I was just wondering what it would take if I decide to go all out some day!

Thanks!

[b-1ken]

The rods and crank will take some abuse. The only problem with stock rods and heavy stock pistons is that they don't like a lot of rpm. The rods "egg shape" at high rpm due to the heavy piston and will pinch the bearings into the crank which will cause them to spin. If the rods have been correctly reconditioned and have good rod bolts, you can buzz it to 7000 rpm without any worry. 6500 would be safer though. I don't see any problem with a 125 HP kit on that engine and if you blow it up, no big deal.

[ehostler]

Of course, I could ask the next question...

Why not consider a ProCharger instead of NOS. A ProCharger is a one time cost and doesn't have to be re-filled. A ProCharger tends to get better fuel efficiency, while producing lots of power.

[dirty dan]

Originally posted by ehostler
Of course, I could ask the next question...

Why not consider a ProCharger instead of NOS. A ProCharger is a one time cost and doesn't have to be re-filled. A ProCharger tends to get better fuel efficiency, while producing lots of power.

Hey ehoster
Just a guess .
But chances are if your useing nitrous fuel econemy is not a real issue.
I realy have zero knowlage of the Pro charger.
But I bet you could get a lot of $30 nos refills with the price diferance.

[WFish]

Thanks for the response! I would use a Procharger if I had the money! Of course I don't really have the time or money for the nitrous either! So I guess a 383 could handle 600 horsepower before it needs a stronger bottom end? Sounds good!!

[ehostler]

Originally posted by dirty dan

Hey ehoster
Just a guess .
But chances are if your useing nitrous fuel econemy is not a real issue.
I realy have zero knowlage of the Pro charger.
But I bet you could get a lot of $30 nos refills with the price diferance.

The ProCharger is always on and has no lag. If you tried to run NOS as an always on, you would be shelling out lots of money.

When properly setup, a Procharger will produce much more power than NOS and still be able to provide better fuel efficiency.

You also don't have to be concerned with a faulty solenoid causing problems. With NOS, a faulty gas solenoid will cause a massive lean out. A faulty NOS solenoid can cause you to leak NOS, when not in use (which is the primary reason most people turn off the bottle, when it is not in use).

I have seen the end results of faulty fuel solenoids and have smelt the faulty NOS solenoids too many times...

A ProCharger is more than worth $3,000 - $5,000.