Motor is freshly rebuilt 454. Bored .060 w/ Flat tops.

How much N2O would be safe to run?

Do heads have to be modified to flow better or can you get away with stock heads?

 

I wouldn't be afraid of a 200 shot or so even if was a completly stock bottom half. Everything is so much bigger in the bottom end they can take a crazy shot of gas .

 

hyper pistons. between 9:1 and 9.5:1 compression.

I'll be running a dual plane manifold carb motor.

What fuel upgrades have to be made?
I heard you must retard the timing...is that true?

I'm trying to build a 3600lb car solidly into the 12's in full street trim. The reason I ask about N2O....

I want to run rather high gears (probably 3.08's) so it will be fully functional on the street and I was hoping the N2O would make up for the lack of gears.

 

some guys i know have a 68 elcamino with 468

motor out of a old wrecker truck. the have powershot 125 plate

and 175 plate as well. total 300 motor has 9.1 compression and

at least 200,000 miles and its been doing this for 6 months.

only thing that has gone wrong is a blown head gasket.

i think it wieghed 4300 pounds and 10.9s on the gas.

hope this helps.

 

Nos isnt going to make up for the 3.08 gear. Your going to have a more of a traction problem with Nos because of all the torque you will be making. What are you going to do with the car? Drag race, Street only, what kinda tires, Slicks, ET Streets?

You can run a 250 shot if you have a good bottom end. Just retard the timimg 2 degrees for every 100 shot of nos and go 2 steps colder on the plugs. Run Race fuel only when running Nos. If your serious about Nos, a timing retard box and a window switch would be the way to go. As long as you follow the rules Nos is safe to use on your motor. Detonation is the enemy. Everything you do will be done to avoid detonation.
Good Luck

Guido

 

No...the car is not a drag car. 95% street car but will have a trip to the track after upgrades just to see what my car is capable of.
I was under the impression that as long as I dont spray off the line...traction shouldn't be a huge problem. I will be using Drag Radials. Like i mentioned earlier...this car will be a driver so the highway gears are a must. I would like to keep drivability but would like the quick kick from the N2O on rare occasions.

To be honest...the N2O will mostly be for show purposes. Rarely used. 100 shot would probably satisfy me.

With such a shot....would a high output mechanical fuel pump surfice?

 

If your gonna run Nos then get a separate fuel pump (Electric) for the Nos. The last thing you want to do is run lean. Is it worth the risk? If you cheap on this and have to repalce moter then what did you save?
I've seen traction as an issue for BBC's that are not sprayed. Depends on your combo. If you break it loose the 3:08 gear will compound the traction loss. Ever see a Caddilac burn rubber for a 1/4 mile. Same principal. Now If you are looking for highjway manners the 3:08 is the way to go. Does the car already have a 3:08 gear? If not why not a 3:55 gear as a compromise? You could also go with the Shortest tire available to help offset the 3:08 gear. You need to find out trans gear ratio and tire size then you can plug all info into DD Dragstrip to get a rough idea of what the car will run.
Will this car be a daily driver, your primary source of transportation?
Guido

 

A window switch would be a good idea for your application.
What kind of car is this 454 in? What kind of heads do you have? What cam will you be running? What trans mission? What tire size? What size carb? Give me that info and Ill run DD Dragstrip for you and gvie you and estimate of what you will run.
Guido

 

Why do you need NOS for 12s?

A good cam in a 468 with even mildly flowing GM heads should get you in the 12s in a 3500 lb car.

Of course, how deep in the 12s do you want to be?

 

That's what I was thinking. Here's what I'm planning for my 91 Caprice. (>4000# car + Little hydraulic roller cam + forged pistons + 467cid + TH400 + 3.08 gears = mid 12s) + >200hp shot N2O = mid-hi 10s I plan on actually using the nitrous to it's max potential and will probably go with a 2 stage set-up with a tight converter. I'll probably go with a little cam with 0* overlap @.050 and a bit more exhaust duration than intake. One of my goals is to pull the front wheels off the ground

I also plan on using the same lobes and LSA on my LT1 after I get some good heads