How Will My 400ex Run With All These Upgrades?

[cheater13]

When i get my 400ex back from being race built all this will be on it:

Top end rebuild
FMF Titanium 4 Exhaust
Powerbomb Header
K@N air filter with Outerwears prefilter
Port and Polished
Stage 2 Hotcam
High Compression Piston
Honda 450r Carb



I am pretty sure that is all he is doing to it because i still want to be able to trail ride it and all. I was just wandering, will this be a good setup for 300ft drag racing? Before i took it to get race built, i had my fmf exhaust, powerbomb header, and the filter setup. I am adding the rest onto it. What do you guys think?

[400exshop]

Who is doing the p&p work ? If you dont know what your doing you can do more harm then good p&p the head.

Who is the builder ? How maney has he built and how do thay run ?

What i would do is put it on a Dyno see what you get stock. Then do all the work but dont p&p it dyno it again look at the TQ and HP numbers see what you have gain.

Then do the P&P you can still use the same head gasket as long as you do it in the step i just told you.....

lol that way you can see where you got the most gains for any later builds you my do or friend my try.

Thats just me and my .02 on any build.

[DragonGunner]

You will see a differance for sure, the hardest part will be getting the carb dialed in with the jetting to match, if you have a good builder he should be able to do this, or at least hopefully get it close. Then you get to decide what gearing an size of tires you like best. My best performance for short drags are 18" rear tires an 16/38...good luck.

[DragonGunner]

Originally posted by 400exshop
Who is doing the p&p work ? If you dont know what your doing you can do more harm then good p&p the head.

Who is the builder ? How maney has he built and how do thay run ?

What i would do is put it on a Dyno see what you get stock. Then do all the work but dont p&p it dyno it again look at the TQ and HP numbers see what you have gain.

Then do the P&P you can still use the same head gasket as long as you do it in the step i just told you.....

lol that way you can see where you got the most gains for any later builds you my do or friend my try.

Thats just me and my .02 on any build.


I agree with the P&P, I talked to several builders an they concurred that the best for the 400EX was a good intake porting but not much of anything but a clean up on the exhaust, too much on the exhaust an you get to much flow an it will actually hurt.

[cheater13]

Elite Performance Racing is doing it. He been building them for 11 years and yeah he said the carb isn't hard for him to dial in. The only thing is I can't really afford tires but I already have holeshots on the rear and it is hard clay I'll be racing on. Also, I still want to field and trail ride it so I wasn't looking too much in gearing