Deciding On 416 Or 426 And Other ???'s

[pmptrk]

After doing tons of searching, I think I am going to build up my basically stock 400 (except for whats in my sig). After combining a lot of post info, I am planning to go with a 450r carb, crf chain, and HRC cam. However, while running a hrc cam with a rev box, I read a few places that HD valve springs are recommended. Is this right??

If I'm going to do the springs, I figured it would also be the time to go with a 416 or 426 while the head is off.

I live in Nebraska, so i do mostly trail riding, but also make an annual trip to the dunes.

1. Are HD valve springs needed with cam and rev box?

2. What would your recommend: 416 or 426? Why?

3. What brand piston and what compression?

4. Any other changes that would be necessary or recommended while doing all of this?

[underpowered]

if you search, you will find many, many threads on this topic.

1. Not needed, but would be suggested

2. Depends. I say a 426, but a 416 is great as well. plugs if you do a 416, there is still room to go to the 426 on the stock sleeve later.

3. JE for the piston, but wiseco is OK. compression depends on the gas you want to run. 11:1 and lower you can runn off premium pump, anything higher requires race gas

4. sounds like you are pretty well on your way to a great quad.

[pmptrk]

while having the head off, is there anything else that i should have done to increase reliability and performance?

[jsmith2232]

I agree with underpowered.... I just built mine with the mods in my sig and it rips. It'll do wheelies sitting down in 5th gear.

1. not needed, some cams highly suggest them.
2.416. why,,,you still have room to go to a 426, your sleeve will be thicker and engine will run cooler, It will rev quicker
3.JE 10.8:1 they are lighter than weisco and about the same as ross, with 11.1:1 and lower compression you can still run 93 octane fuel. the only place i could find the je was from c&d racing ( this sites sponsor) and it ran 110$
4. Good luck