383 LT1 stock heads with nitrous?
383 LT1 stock heads with nitrous? I am in the process of making a 383 Direct Port Nitrous LT1, my question is until I get the money to port out the heads and put new springs, retainers, valves and everything else that you could possible be done to make the head stronger. Can I shoot a 150, maybe 200 shot of nitrous on the stock heads as long as I don't go past redline. For some reason I thought I read that the components in the head wore out or float only by going past redline. I will probably have to get some arp studs to hold the head down though, right? Thanks for any help.
TECH Apprentice
Joined: Aug 2004
Posts: 362
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There are a couple of things wrong with your post....I thought it was a rule that "stock heads" and "383" were never supposed to be in the same sentence together. You just broke a huge rule.
Why are you building a 383? Did you blow the current setup? If all you're looking at is a 150-200 shot, why not just upgrade the pistons and maybe rods on the current setup? That would save quite a bit of money to start doing things right. You could spray 200 all day long on the stock crank and forged pistons/rods and you'd have the $$$ to have your heads ported and a cam to match which would put down much better results than a choked 383.
A little more info on the current setup and why you're going to spend the money on a 383 but leave the heads stock.
Why are you building a 383? Did you blow the current setup? If all you're looking at is a 150-200 shot, why not just upgrade the pistons and maybe rods on the current setup? That would save quite a bit of money to start doing things right. You could spray 200 all day long on the stock crank and forged pistons/rods and you'd have the $$$ to have your heads ported and a cam to match which would put down much better results than a choked 383.
A little more info on the current setup and why you're going to spend the money on a 383 but leave the heads stock.
Direct port? On stock heads, on a 383?
Good luck with that. I'd be suprised if it made over 400rw with a 150 shot. There isnt enough flow there to support that kind of air/exhaust flow.
Good luck with that. I'd be suprised if it made over 400rw with a 150 shot. There isnt enough flow there to support that kind of air/exhaust flow.
I'm confused why there wouldn't be enough air flow. If I give a 150 shot nitrous with the 383 at lets say 3500 rpm's I would think there would be just as much air flowing through the ports in the head as the 350 if not a little bit more, but due to the fact it is a 383 I could easily fit alot more air in there so I am choking it a bit. Am I not right? Also I do plan on going with Lloyd's LE3 when I get money. If someone was to tune the 383 with the stock heads would it run too rich or too lean, if it is too rich could they lean it out somewhat. Thanks again.
Teching In
Joined: Jan 2005
Posts: 18
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a 383 will need more air than a 350 will at the same rpm. stone stock heads especially with a stock cam and a 383 I think would be slower than a bolt on car. Are you planning on keepin the exhaust manifolds to? wait till you get the money to do it right
I will be getting the coated long tube pacesetter headers. So if I have all the bolt on's to a 383 w/ stock heads would you still think the 350 with bolt on's and stock heads have more power. I still don't understand why there would not be enough airflow with the 383 for that shot of direct port nitrous, what exactly do you mean by not enough airflow. By that do you mean a 150-200 shot of nitrous with a 383 and stock heads will not be able to suck all the nitrous into the cylinders like it would with a 350 and stock heads? I don't doubt any of your knowledge, I doubt mine so that is why I am asking. Thanks again.
Again I do plan on getting my heads ported later on, but I am anxious to get the power now, and figured I could do so with the direct port system since it would be cheaper.
Again I do plan on getting my heads ported later on, but I am anxious to get the power now, and figured I could do so with the direct port system since it would be cheaper.
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TECH Apprentice
Joined: Aug 2004
Posts: 362
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What he means is the stock heads are choked with the stock displacement. You add 33 more cubes which equates to more air and add that much nitrous on top which is even more trying to get out of that little exhaust port and you're choking the hell out of your motor.
So yes, a stock displacement motor with worked heads and matched cam has a decent chance of outperforming a bolt-on 383 with stock heads.
What you're not realizing is that the power comes from the heads. There are 350's that put down more HP than 383's due to their heads/cam setup. Strokers help....more with torque but you aren't going to make near the power if you don't invest wisely in heads.
And a fogger setup would be far less expensive than a direct port setup.
So yes, a stock displacement motor with worked heads and matched cam has a decent chance of outperforming a bolt-on 383 with stock heads.
What you're not realizing is that the power comes from the heads. There are 350's that put down more HP than 383's due to their heads/cam setup. Strokers help....more with torque but you aren't going to make near the power if you don't invest wisely in heads.
And a fogger setup would be far less expensive than a direct port setup.
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Do you already have the driect port kit? If not why don't you just put that money towards getting your heads ported and a custom cam. That will give you a ton of power, then later get the direct port. It will be better if you do things in order IMO.
Staging Lane
Joined: Mar 2005
Posts: 68
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I would agree that you are probably doing things backwards. I would get the heads first and then when youve saved some more $$, pull the motor and stroke it. These guys are right in saying that the heads and cam are where the power is. I know my motor is choked a bit due to the mild cam. Ive got the cubic inches and a decent set of heads, but if the cam isnt allowing the valves to open enough to allow enough air flow, it doesnt matter. Power is always going to be limited by the most restrictive area to airflow. Once the 350 cubic inches can breath with a nice set of ported/aftermarket heads and cam, then its time to stroke the lower end in an effort to flow more.
