one more question...

[Bandit72]

then i'll leave yall alone for awhile 

ok current plans are

451 stroker kit from 440source
84cc edlebrock heads,
comp cams xs2825 stick
roller 1:5 lifters

this question revolves around compression ratio...
i've heard that aluminum heads drop c/r is that true? i dont' understand how...i thought the chamber size/shape determined that...
the pistons that 440source offers will only give me 9.85 c/r at the best (thats according to there little chart thing and i'm assuming thats with cast heads) but they say they can get me flat tops if i want....should i go with the flat tops or will there be valve clearance issues? i am aiming for around 10:1 - 10.5:1 c/r

Thanks Ryan

[jg68]

then i'll leave yall alone for awhile 

ok current plans are

451 stroker kit from 440source
84cc edlebrock heads,
comp cams xs2825 stick
roller 1:5 lifters

this question revolves around compression ratio...
i've heard that aluminum heads drop c/r is that true? i dont' understand how...i thought the chamber size/shape determined that...
the pistons that 440source offers will only give me 9.85 c/r at the best (thats according to there little chart thing and i'm assuming thats with cast heads) but they say they can get me flat tops if i want....should i go with the flat tops or will there be valve clearance issues? i am aiming for around 10:1 - 10.5:1 c/r

Thanks Ryan

Bandit, i would shoot for 10.5.1 with the aluminum heads, it'll still run on pump premium, you can mill the heads .030 & acheive that with the F/Ts

BTW, you'll LOVE that 451, is it a low deck?

[firefighter3931]

  10.5:1 with a zero deck shortblock is ideal for a pump gas street/strip build. Get the quench as tight as possible for maximum power and detonation resistance.


Ron

[Bandit72]

what will i have to do to the intake to make it match up properly after i mill the heads?

[firefighter3931]

what will i have to do to the intake to make it match up properly after i mill the heads?

You won't have to mill the heads as long as the shortblock is properly built. When the rotating assembly is mocked up the block is decked to achieve a zero deck...meaning the pistons are flush with the deck surface. The head gasket creates the "quench zone" and provides the required piston to head clearance. You will have to order the correct pistons for the application.


Ron

[70charger_boy]

Firefighter can you come over to my house and build me a motor as nice as the one in your profile?? pleaseeeeeeeeee

[Bandit72]

what will i have to do to the intake to make it match up properly after i mill the heads?

You won't have to mill the heads as long as the shortblock is properly built. When the rotating assembly is mocked up the block is decked to achieve a zero deck...meaning the pistons are flush with the deck surface. The head gasket creates the "quench zone" and provides the required piston to head clearance. You will have to order the correct pistons for the application.


Ron

i read in my "engine blueprinting" book that you don't necessarelly want 0 deck because when the engine is running high rpms, the rods can seem to "stretch" and may come in contact with the head..is this true or is the book wrong? I can get  pistons from 440source if i go with the 400>470 kit that will give me  -.002" deck height....the best i can get from them for the 451 kit is  -.025"...

sorry for all the questions again but like i say, i'm building this myself and want to make sure i do it right the first time....

[jg68]

what will i have to do to the intake to make it match up properly after i mill the heads?

You won't have to mill the heads as long as the shortblock is properly built. When the rotating assembly is mocked up the block is decked to achieve a zero deck...meaning the pistons are flush with the deck surface. The head gasket creates the "quench zone" and provides the required piston to head clearance. You will have to order the correct pistons for the application.


Ron

i read in my "engine blueprinting" book that you don't necessarelly want 0 deck because when the engine is running high rpms, the rods can seem to "stretch" and may come in contact with the head..is this true or is the book wrong? I can get  pistons from 440source if i go with the 400>470 kit that will give me  -.002" deck height....the best i can get from them for the 451 kit is  -.025"...

sorry for all the questions again but like i say, i'm building this myself and want to make sure i do it right the first time....

When i had my 451 built, they set the pistons .009 below deck, you want to try & acheive about a .035-.040 quench, so if you put the piston down around .006-.008 & get a .030 gasket, this will put you there, on my 451 the heads were 90cc irons, with a .039 gasket & F/T Ross .009 in the hole, my comp. was 9.73, it wouldn't hurt any to mill .030 off the heads to get closer to 10.5.1 with the aluminum heads.

[firefighter3931]

i read in my "engine blueprinting" book that you don't necessarelly want 0 deck because when the engine is running high rpms, the rods can seem to "stretch" and may come in contact with the head..is this true or is the book wrong? I can get  pistons from 440source if i go with the 400>470 kit that will give me  -.002" deck height....the best i can get from them for the 451 kit is  -.025"...

sorry for all the questions again but like i say, i'm building this myself and want to make sure i do it right the first time....

The engne book is correct to a degree, but does it specify what the head gasket thickness is when making that blanket statement ? The safe measurement for a steel rod street/strip build is .040 allthough some will try to push it to .030-.035 I'm not saying that it won't work that tight but you're pushing it when you don't really have to. 

How you get the .040 clearance is entirely up to you....zero deck with a .040 gasket or .005 below deck with a .035 gasket....same difference.  If 440 source doesn't have the right pistons then you have 2 choices.....deck the block or have them custom order what you want....which they will do. The zero deck is the most popular way to go because most head gaskets are commonly available in a .040 compressed thickness (Felpro 1009) while a .035 gasket is custom from a manufacturer (Cometic) and cost ~$150.00 a pair.

Engine building the best  way isn't easy and you should take the time to plan it out properly if you want it to be reliable. 


There is another member who went through the same thing when he decided to build his stroker. Read through this thread and you will get a better understanding of the whole machining and quench build idea.


http://www.dodgecharger.com/forum/index.php/topic,782.0.html



Ron

[Runner]

i personally dont buy into a power loss using aluminum over iron heads.   and even if you did id still take a 9.0-1 e headed motor over a 10.0-1 stock iron headed motor.


    my car ran a best pass of 11.80 with stock 906s,  swaping to eheads it ran 11.35.    i have a 452 ( 400 block) with flat top pistons .007 in the hole with 5cc valve reliefs. comp xe282s solid cam tm6 intake and hooker 1 7/8 headers.   id guess you should see simular results.  i used the short rods in my motor.  also my box stock e heads cced beteen 82 and 83cc. the 906s they relaced cced at 87.   

     if you use a flat top piston you should get the compresion up to between 10.3-10.6 depening on valve notch cc and how far they end up in the hole.   my quench is .047 my 400 block is bored .040 over and the 1009 sometimes has problems hanging over in the bore with larger bored engines.   good luck   im sure youll be really happy.

[Bandit72]

ok, now i'm leaning toward the 470 kit...idk why but i'm probably the most undecisive person on the planet.... the kit offers pistons with -.002 deck height...so if i go with those and the .040 felpro gaskets i should get .042....would decking the block those extra .002 make a noticable difference or would it be ok like that, i got from another one of Rons posts that .040-.060 was fine


Thanks Ryan Olson

[firefighter3931]

Ryan, .042 is fine. Make sure that the compression ratio is in the 10.5:1 range with those pistons and your 84cc heads.  The 470 is a good option and will make more power for the same price as the 451 setup. 


Ron

[Bandit72]

440source says it'll give me 10.77:1 with steel heads...

[jg68]

440source says it'll give me 10.77:1 with steel heads...

You'll get more comp with the longer stroke, this will work out great, like Ron said, the 470 is as simple as the 451, i wouldn't worry about .002, just use the .040 gasket & you'll have over 10.5.1 with the 84cc & 470 cubes, you'll more then likely be closer to 11.1

[Challenger340]

Note;
Be careful when measuring "0" deck for block milling, not to forget, and account for, Piston "rock" in the cylinder.