360 to 408

[74swingerlover]

just wondering what parts/specs i need to get the 408 up to around 450 horsepower? such as cam, intake carb, heads. i want a roller cam andgoing to go with 1.7 roller rockers. i know i need a 4 inch crank. Will i need to have the cylinders bored to clean up the walls or can they remain stock?

this is what I think I need:
360 block
4" crank
.510 lift roller cam
new bearings everywhere
aluminium heads (probably go with edlebrock RPM) with good springs and roller rockers (1.6 or 1.7?)
M-1 intake
750 double pumper
good distributor and MSD box(6AL)
anything else?

 

[340sixpack]

450 can be had easy without the expense of a roller cam.Why 1.7 rockers?Do
you already have them?

 

[lhearold]

Go with a Magnum engine (already set up for roller cam), bore 0.030, Eagle Forged 4" stroke crank, rods, and 10:1 pistons, balanced (internal). Are you going carb or EFI? Talk to the guys at Mancini. They can recommend a cam either way. Cast iron Magnum RT heads cleaned up with the HD springs. Stay with the 1:6 rocker ratio. More than that you are going to have to do some serious head work. The Magnum RT heads will take up to a 0.520 lift without having to do any cutting on the valve guides. I am running a setup like this with a mild EFI cam (mine's EFI) and I have dyno'd 455 HP at the rear wheels. Still sreetable on Premium fuel. Plenty of get up and go for my 69 Dart.

Larry

 

[sumbitmopar]

You might want to look into the EQ heads (Clearwater Cylinder Heads in Fla.). Great bang for the buck. Don't need 1.7 rocker arms. Get a good timing chain/gears, match your cam and valve springs, good oiling system, performance curved distributor, good harmonic balancer. Have Fun!

 

[fishy68]

If your stroking it definitely do a full treatment on the block such as bored and honed with torque plates. Decked. Align hone if needed (your machinist can tell you if it needs it). Use new SCAT I-beam rods or Eagle I beams if you prefer but the SCAT's are better material. Have the assembly internally balanced. Use forged pistons as the side loading on a 4" stroke is quite high. The high side loading is also a good reason to bore and hone with a torque plate. Makes for better ring seal. Use a Eddy Air-gap intake instead of a M1 and you'll have more low end torque and it'll still make 450 hp. Use Eddy heads if you want but remember they have had issues and will need gone through by a good machinist. The EQ heads Subitmopar mentioned will make 450 hp with very little work. But by the time you get done buying all the needed stuff to make them work (ask me how I know this, LOL) there isn't much difference in price (if any) and the Eddy aluminum heads are lighter since their aluminum and they will also make 450 without much work. No need for a roller cam but if that's what you want it's your money. Remember if you don't have a roller block a roller kit for a LA block is big bucks. I also ask why you'd want to run 1.7 rockers? Do you have them already? More than likely you'll need to do some more grinding on the heads to make the pushrods clear. But they do have a slight advantage of straightening out the bad lifter to pushrod angle on a small block.

 

[74swingerlover]

that bring me another question....... what compression ratio should i go with? 10:1? what type of pistons should i use? flat or dish? forged was the way i was going to go with pistons and crank.

 

[70aarcuda]

as far as compression....make a decision on the cylinder heads first...

some heads can live with higher compression then others...especially aluminum.