top end question...

[Mitseclipse101]

i have the turbo now, and i am looking to boost more, i am planning on building the bottom end this winter while the car is garaged, but my question is how much power can the top end handle, i am wondering about the cams, valves, and head, i heard that the head of the 420a is more reliable then the bottom end, i was wondering if this is true, and if so can anyone elaborate, thanks

 

[green95hrcgs]

The heads on our cars can take a lot. As far as I know, HRC is still using the stock head on their RS drag car, and they are making 500-600hp.

 

[Mitseclipse101]

hmmm... now are they using the stock internals in the head too, like the valves, cams, etc, or is it a stock head that is built, anyone know?

 

[green95hrcgs]

As far as I now its all stock.

 

[siueclipse]

As far as I now its all stock.

it is all stock. keep in mind that whp number posted was with spray.

 

[DSM-ZERO]

You will still neeed to replace your valves with better one's you would not want to bend one of thouse at high boost.
Some of our valvetrain wont hold up to lot's of boost

 

[leakyfaucet]

You will still neeed to replace your valves with better one's you would not want to bend one of thouse at high boost.
Some of our valvetrain wont hold up to lot's of boost

The amount of boost isn't what bends valves. It's the speed the valves are going. And it wouldn't be the valves you need to replace, it would be the springs. The valves bend when the springs can't keep up with the speed they're moving at and that slight delay causes the pistons to crash into the valves.

 

[DSM-ZERO]

yes the spring's keep the valve closed at high rpm and boost if you want to go higher rpm and boost get new springs because the stock one's will not keep the valve shut.
and the valves can bend for a couple of reasons
high boost
too much heat
it can float and a piston can hit it