I'm not sure the second post was really sarcasm, it could legitimately been a thank you he forgot to post in the original message.
I mean, he did go back and add a "thanks" statement a few min later.

Welcome to the board, hopefully you are still around and reading replies.

To answer the original question, 450 at the flywheel wouldn't be too tough at all.
450 at the wheels may be possible as well, but it's bit of a stretch without increasing volume
or using power adders (NOS, turbo, surpercharger).

1) Maintenance (regular fluid/filter changes, relace worn hoses/belts, etc...)

2) The small stuff (alum driveshaft, eWater pump, etc ...)

3) Let it breath (cold air intake, headers, 3" exhaust)

4) Ported heads, manifold and custom cam (You will probably need larger injectors and a larger throttle body here as well)
(work with the porter and cam supplier to get the right combo for you application)

4.5) The bang:buck ratio kinda drops off here IMHO but IF it's within your budget,
a quality forged/balanced bottom end rebuild or shortblock purchase will really help you towards your goal here)

5) Follow up with a quality custom tune to match your build.

Remember that to make it streetable, you will want to look into suspension (including tires)
and drivetrain (clutch/torque converter/gears) mods. They won't make more power,
but they will make it more fun to drive

Different vendors cater to different people.
It really depends on your budget and taste.
I found that the best way to research which is "best" for me, is to see what others are
using and what they say about them. If someone is unhappy with a product, you can be
sure they will speak their minds. Likewise, products that work well get a good deal of praise
from the board members.

 

The difference in power to go from 10.5 to 12:1 is only about 2%. In an all out race motor, by all means use the most compression you can get, but for street use 10.5 is sufficient and much safer given todays pump fuels. I am running a 383 with 10.4:1 ported lt4 heads flowing 270cfm @.600, but my cam, a cc306, only goes to .570 with 1.6s. A ported lt4 intake and custom tune laid down 417rwhp @ 6600rpm. To get 450 will require just a bit more than mine, which is why I made those recommendations. There are many ways to build power, and like some others have said, you need to figure out which way is your way or pay someone to do it. BTW, 10.5 is not low compression and 300 cfm is not too easy to acheive in lt heads.

 

10.5 is STOCK.
I run 13.3 on pump gas,it's not the static it's the DCR your engine sees.
Just adding compression without changing anything else you are right with the 2% but the higher compression allows ya to run larger cams which make "MO HP" so don't knock BIG static compression until ya have tried it.
Like I said it's the DCR that counts.

 

Not knocking big compression. Just saying that it is not very appropriate for street use. Race use, great. Just because you can run 13, does not mean that everyone can. 13 is pretty high and requires careful porting, cam selection, and tuning, all of which someone wanting just a driveable 450rwhp is probably not wanting to undertake. At the very least, you must concede that 13 is not as safe and manageable as 10.5. Higher compression will require longer duration and greater overlap, which will have adverse effects on idle quality and emissions. If you could safely run 13:1 and get good mpg, reliable operation under all conditions, and pass emission testing, don't you think the manufacturers would be doing it?

 

8-9psi from a turbo, and hope the stock shortblock will hold on. You can do this on stock heads and cam.

 

no they wouldn't. you ask why ? cause they will never spend the money on higher quality parts to allow it. cheap & fast to put together, thats what they will always build. its up to us to buy the parts and do what we need to, if we have a goal as far as hp or et. the factory will never do it for us. i think the closest thing is the GT and the other 2 cars that share that platform. kind of sad chevys only performer is the corvette these days.

 

Well don't have to worry 'bout emissions or whether the General does it or not. Ya DO see compression creeping up as it was in the '60's
Yes ya got to have the knowledge to build one with that much static but it CAN and HAS been done a bunch. The General is going to do the very least it can do to be competitive and not spend the money to run static that high.

 

You got that backwards.



And...

Big cam + low compression = TURD!

 

What your missing is that higher compression is necessary with a long duration, high overlap cam. The longer the overlap, the more compression is bleed off. Raising the static compression ratio will regain lost dymanic compression (basically the amount of pressure you would see in a compression test). Statistically you could run that big cam, raise the compression 1.5 to 2 points and not require a much higher octane fuel.

But with a stock or low duration cam in a street driven engine. High compression is asking for problems and will require high priced fuel to run right.

IMHO 450RWHP in a DAILY DRIVER is too much to shoot for unless your using boost of some kind. If it's your second car and a weekend play toy, go for it!

RE'

 

I am not missing anything. I am well aware of the requirements of high compression. I am merely saying that I don't feel it is appropriate for street applications. That is all. My opinion. I know there are a bunch of guys doing it. What you may be missing is that with higher duration and overlap, you raise the rpm at which peak hp is generated, and this necessarily means that the low end will suffer. How much depends on the cam. Actually Hp is a mathematical equation based on RPM and torque. The formula is HP=(torque * RPM)/5252. Also, more overlap and duration necessarily wastes fuel at idle and low rpm, unless you have variable valve timing. Anyway, it my opinion and I would not build a high compression engine for myself or anyone else if it is intended to be a daily street driver. It is far better to keep compression below 11:1 and run a bigger motor.

 

Did you compleatly miss the part about how much power he wants to make????

He NEEDS a large cam, which in turn NEEDS higher compression.

RPM = POWER

Run a bigger motor?? We are already talking 383, this is LT1 no aftermarket block availible.

 

A higher compression motor that is set up correctly will be cleaner burning and more efficient, hense more MPG than a lower compression motor

On edit: Why do you think OEM's are increasing combustion chamber efficiency and compression....cleaner burning and better fuel milage with power as a side effect.

 

It appears ya missed the BOAT.

Cam design today can be made through ramp rate to reduce the overlap and have the IC where ya need it.

Ya can keep the compression below 11-1 but CID to CID I will out run ya with 13-1