I found this question posted else-ware rather interesting


The Grumpy Grease Monkey mechanical engineer.
Staff member
I know that this discussion has been gone over many times. I asked almost the same question a few years ago but would like to get a real discussion started. Here is my question. My combo with a low port head can weigh 3050. At this weight I can run a 42 nitrous jet. If I switch to a raised runner 23* head I have to weigh 100 lbs more and 13-18* has to weigh 150 lbs more. All other combos can run a 40 jet. My thought is can I make that much more na to compensate for the extra weight? My combo is 434 Afr 245 that have been extensively gone over. It’s makes a honest 740 hp. I know some may like this head and other don’t. My feelings will not be hurt if anything is said one way or another. Let’s hear what you have to say. Thx
the injection of nitrous oxide into an engine means that more oxygen is available during combustion. Because you have more oxygen, you can also inject more fuel, allowing the same engine to produce more power. Nitrous oxide is one of the simplest ways to provide a significant horsepower boost to any gasoline engine.

Nitrous oxide has another effect that improves performance even more. When it vaporizes, nitrous oxide provides a significant cooling effect on the intake air. When you reduce the intake air temperature, you increase the air's density, and this provides even more oxygen inside the cylinder.

now keep in mind that this answer posted below,
referred, to power potential on a non nitrous assisted engines, N/A
vs the similar engine using nitrous.
and just as obviously we don't have all the required info and dyno sheets
the engine info we have is limited at best,
which puts us at a disadvantage at least in theory his engine has, or at least potentially should make,
a certain amount of power ,using head air flow to calculate max potential power.
a 30%-35% boost over the same engine running, without nitrous assisted power, is a rather common assumption,
but obviously we don't know his compression, cam timing, or how much nitrous hes using,, his gearing etc.
thus if his nitrous engine makes his claimed 740 hp
he never posted the cam lift, true intake flow with the heads attached and info on the headers, rpm, or posted a dyno power chart.
we don't know if the cars running a tunnel ram/dual dominator carbs or a single large carb,
,that set of heads on a 434 displacement should be making about 35% less N/A ,
or about 500 hp N/A ,compared to a nitrous boosted combo.
with the engine built to similar specs to run without nitrous, if its making about 740 on nitrous.
thus he already in theory has not yet reached the max performance his combo is in theory able to make.
keep in mind the heads might flow 345 cfm on a flow bench,
but his cam, duration & lift, headers and collectors, intake manifold etc.
may not allow the ports to flow nearly that well when everything's bolted up and running.

if we look at the AFR 245 heads,
245cc Competition Flow Chart

Test conducted at 28" of water (pressure) on Superflow 600

A useful tool for calculating the power potential of cylinder heads is the following formula HP=. 257 x (peak) airflow x number of cylinders. If we plug in flow data from a CNC-ported small-block cylinder head that offered a peak flow of 304 cfm, we get the following: HP=. 257 x 304 x 8 or 625 hp.
you can play with this calculator,(link below)
and play with the figures too calculate the difference in horse power vs weight vs E.T. and MPH,
but at least looking at the very limited facts, posted
Id think his current engine using nitrous could be re-tuned,
we don't know the cars gearing, peak mph, 60 ft times ETC.
so were guessing, but on the very limited info provided,
Id think he is still leaving a small bit of power potential untapped.
or his car could be made a bit lighter weight, before he drops big bucks in newer heads

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