Duromax 440 build-reving it up!

[Notsoezgo]

Final teardown

[Notsoezgo]

Here is my build list so far, all.parts ordered :
1) HD valve train components, 50# valve springs, chrome moly pushrods, 1.1 to 1 ratio rockers
2) ARC billet connecting rod
3)ARC flywheel
4) Vegas Carts "cheater torque cam"
5) new gaskets
6) nr racing oil catch can
7) top plate
genuine honda carb with adjustable idle jet, adjustable main jet

[Notsoezgo]

I am also using studs in place of bolts on side cover and head. A 6 degree offset timing key will go in the flywheel.

[raydhd]

The only question I see on your list might be with the 50 lb springs on the torque cam. It might not be quite hard like a billet cam and the cam itself doesn't need that much spring as it is not too radical.

[Shepard]

Your wasting your valve train with 50 lb springs. 32lb springs are good to 6000 rpm. Why wear out the cam? Things like stainless steel valves and titanium valve spring caps and keepers -- these are the parts that will bullet proof your valve train in a 4500-5000 rpm engine.
Porting really wakes up these little engines. The simplest of things like port matching the carb insulator to the carb and then to the head. A dremel and some sanding drums and a small burr. Both the intake and exhaust can be opened up, the exhaust needing the most work. I'll stop rambling now

[Notsoezgo]

Originally Posted by raydhd

The only question I see on your list might be with the 50 lb springs on the torque cam. It might not be quite hard like a billet cam and the cam itself doesn't need that much spring as it is not too radical.

Thank you, so I've gone ahead and ordered 35# springs from Vegas Carts.

[Notsoezgo]

Originally Posted by Shepard

Your wasting your valve train with 50 lb springs. 32lb springs are good to 6000 rpm. Why wear out the cam? Things like stainless steel valves and titanium valve spring caps and keepers -- these are the parts that will bullet proof your valve train in a 4500-5000 rpm engine.
Porting really wakes up these little engines. The simplest of things like port matching the carb insulator to the carb and then to the head. A dremel and some sanding drums and a small burr. Both the intake and exhaust can be opened up, the exhaust needing the most work. I'll stop rambling now

I went ahead and ordered 35# springs from Vegas Carts, I will consider porting too. Thank you.

[Notsoezgo]

Does anyone know the # rating for the stock gx390 clone valve springs im curious

[Notsoezgo]

Does 29# sound about right for stock springs?

[raydhd]

One other note since you are using an advance key BE SURE to do the lapping procedure with the flywheel installation. I didn't know they still did the advance keys with the big block clone. One other note there are BIG flow gains by opening the valve pockets below the valve seat . Just be SURE to protect the seat while doing this.