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Discussion Starter · #1 ·
Good afternoon. I’m just looking for some pros and cons with using the stock blower and M311 Frankenstein heads with either block. Thanks in advance
 

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I’m looking online but not too comfortable. Can someone point me in the right direction as far as vendors go
 

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Discussion Starter · #8 ·

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Good afternoon. I’m just looking for some pros and cons with using the stock blower and M311 Frankenstein heads with either block. Thanks in advance
Don't change your pulley ratio. . .

With the larger volume engine (427) the little blower will fill the engine,
and make about the same HP. HP won't increase!

But the torque below the Peak HP will increase, as the volume
has changed, per the units of time / rpm.

Torque will increase, assuming you don't lower the static compression ratio.

If you desire to increase the HP, then put on the larger blower later if you wish.

**

Simple rule of thumb regarding calculating torque.

-on gasoline-
NA Engines; Multiply CID by static compression ratio, and divide by ten.
FI Engines; multiply that value by your density ratio.

Here the compression ratio is 10.0;1
The last value is the density ratio.

(427 * 10 / 10)= 427 lbs ft.
(427 * 10 / 10 * 1.41) = 602 lbs ft.
(427 * 10 / 10 * 1.75) = 747 lbs ft.

-move compression ratio up to 12.0:1
(427 * 12 / 10 * 1.75) = 897 lbs ft.

Here we see the importance of the increases of both the
static compression ratio, multiplied by the density ratio.

Big motor, roots blower, makes 'Big Torque' numbers!

Again, this is a simple 'Rule of Thumb' equation.
Kind of get's you into the ball park, but not exact.

And as the density ratio and compression ratio increase, so does ones octane level..lol

Cheers
 

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Discussion Starter · #10 ·
Don't change your pulley ratio. . .

With the larger volume engine (427) the little blower will fill the engine,
and make about the same HP. HP won't increase!

But the torque below the Peak HP will increase, as the volume
has changed, per the units of time / rpm.

Torque will increase, assuming you don't lower the static compression ratio.

If you desire to increase the HP, then put on the larger blower later if you wish.

**

Simple rule of thumb regarding calculating torque.

-on gasoline-
NA Engines; Multiply CID by static compression ratio, and divide by ten.
FI Engines; multiply that value by your density ratio.

Here the compression ratio is 10.0;1
The last value is the density ratio.

(427 * 10 / 10)= 427 lbs ft.
(427 * 10 / 10 * 1.41) = 602 lbs ft.
(427 * 10 / 10 * 1.75) = 747 lbs ft.

-move compression ratio up to 12.0:1
(427 * 12 / 10 * 1.75) = 897 lbs ft.

Here we see the importance of the increases of both the
static compression ratio, multiplied by the density ratio.

Big motor, roots blower, makes 'Big Torque' numbers!

Again, this is a simple 'Rule of Thumb' equation.
Kind of get's you into the ball park, but not exact.

And as the density ratio and compression ratio increase, so does ones octane level..lol

Cheers
Mr rubber duck,

i have been waiting for you to chime in and I got it. So larger supercharger to make more hp because of the larger volume motor. As far as compression ratio goes, what should be my target say for a 427 and a kong 2650? That part I’m a little in the dark on.
 
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Mr rubber duck,

i have been waiting for you to chime in and I got it. So larger supercharger to make more hp because of the larger volume motor. As far as compression ratio goes, what should be my target say for a 427 and a kong 2650? That part I’m a little in the dark on.
93 pump or ethanol?

What cam?

Sent from my SM-G991U1 using Tapatalk
 

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Discussion Starter · #12 ·
93 pump or ethanol?

What cam?

Sent from my SM-G991U1 using Tapatalk
Both sir. I’m going with the BTR stage 2 cam and Monster m311 Frankenstein heads
 

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Much easier to build big torque with the larger volume engine, then it is to make big horsepower with a larger volume engine.

I worked with several people 5 - 8 years ago with large volume engines, high compression, small blower and mild cams.

Big torque at lower engine RPM, didn’t matter about the horsepower to those people, as it’s just a bragging right.

11.0 to 11.25 Compression Ratio with them.
228* and 231* duration camshafts.
Bigger cam was tried, just idled rougher and more difficult to tune.
Best results 5600 to 5800 rpm.
850+ & 875 lbs ft torque.
Put a bigger blower on the 875 engine, and it went to 901...Big deal!

Very drivable and Engines were easy to tune.

Must use E85 with the high compression ratio.
If not, torque was down about 100 lbs ft, as a proper tune could not be used.

Also, little blower can’t fill the cylinders properly above approximately 5000 RPM.
LS 7 TB used.

Touch the throttle and the tires turned to grease.

Better heads a must!
If heads are too small, torque range / rpm span highly limited.

Cheers
 

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Mr rubber duck,

i have been waiting for you to chime in and I got it. So larger supercharger to make more hp because of the larger volume motor. As far as compression ratio goes, what should be my target say for a 427 and a kong 2650? That part I’m a little in the dark on.
Your heads use the 2.165 inch intake valve… Correct!

Regarding compression ratios. . .
How much more HP do you want to make, over and above your 376 LSA?

If I am correct regarding the intake valve size on your cylinder heads, you can easily make 850 hp two 875 hp with a very drivable car. With a larger engine, you pull in more air and fuel per RPM.

This means you don’t have to spin the engine high to make an easy 850 to 875 hp. This is a very big plus in my mind, regarding a street driven car.

Let’s talk about compression ratios again after discussing this out a little more thoroughly.

Also, I do not believe in GM sells an assemble short block with various compression ratios.

So you would have to have your engine built by an independent if you desire more compression ratio than their short blocks have.

Cheers
 

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Discussion Starter · #17 · (Edited)
Please see attached for head information. I only want to get 800whp. But if can make 850-875 easy, that’s what I want.
 

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Please see attached for head information. I only want to get 800whp. But if can make 850-875 easy, that’s what I want.
This is a good number to shoot for; easily within the range for those heads and that number keeps you away from the abyss that is the pursuit of the 'max effort' numbers.
 

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