Building a stroked LA (410 cu) and considering install of bigger valves in my Eddy heads to support increased airflow requirement. Current 2.02/1.6 valve arrangement has .060" spacing between the valve margins. Going to 2.08 intake valves would cut the spacing to .030". What's the generally accepted minimum clearance between the intake and exhaust valves? Regularly driven, naturally aspirated, street and off-road truck with 230*/236* roller cam retrofit, RPM intake, and headers.

Thanks,
Ty

Bigger intakes will increase overall HP but will cost bottom end HP and torque. I don't recommend it for a below 5500 engine. The gain is minimal in a steet or off road vehicle.

Call up a pro porter like Dwayne Porter and ask him. IMHO you'd be better off having the heads pro ported than just installing larger valves.

R.

If your doing that you need more Cubic Inch and cam. I would leave it alone and concentrate on the port design and approach under the valve. Larger valve with no support of cam or cubic inch you would be making a move in reverse in my opinion.

logan426

Appreciate you all's comments and concerns. Figured that if I was doing all the work on the lower end and stroking it out I might as well get the top end in order too while it was apart. I'll take your advise - I'll do some port cleanup/mild porting and talk to my local machine shop. Owner is a MOPAR guy.

Thanks,
Ty

In my Eddie heads I have the 2.08 intake and a 1.625 exhaust.
http://youtu.be/v2lldMmyg5I

Nice!

On a flow bench, bigger intake decrease low lift flow and increase high lift flow. A litle releaf with bowl porting will give better all around performance. A big cam will ceacrese street throtle response unless you have lots of stall. Can you say 7-8 MPG?