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pwrpapa

650L head porting.

6 posts in this topic

How much does head porting help a 650L.

I've done a lot of porting on my 408 stang and other rods i've owned.

So would it help out the 650L ?

Is there any sites I can look at for info?

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Does it seem to make a difference or is it a waste of money?

I know the head has splayed valves on the L and the R has a inline valve design.

I would think the L head would have lots of potential.

Thanks for the links.

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I think that porting by itself wont do ya much especially if you are using the stock head pipe and exhaust. Appearently just changing those(and jetting of course) with stock porting nets a noticeable gain.

I cant speak for the head pipe but I did go from 152 main to 160 main and shimmed the main needle in my stock Khien carb, this combined with a new aftermarket pipe has made a new machine. :applause::banghead:

Back to porting: it is the creme de la creme of engine mods with respect to RFVC motors, considering how much they are choked by perephrials. Just like with V8s etc porting by itself doesn't do much without the capitalization of a larger cam, better valves, etc.

Just some thoughts

Rob

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Well worth it IMHO.

I did my head myself and the engine runs very well (though I do run a aftermarket carb and custom made race pipe)

You dont need to remove a lot of metal. The main areas to concentrate on are the leading edge of the web on the siamesed intake port (needs thinning and knife edging, reduce the valve guide protrusion, tidy up the valve seat to intake tract area (was especially rough on my motor) and match the intake ports to the inlet stub and the ex. ports to the headers. Doing this will definately improve torque.

My motor is now 50+HP at the back wheel (as its overbored and running a 9.4mm lift cam) and Im sure a few of those ponies are from the head work I did.

The one big shortcoming on the 650L in terms of tuneability is that theres little scope to put bigger inlet valves in reliably. The heads tend to crack btwn the valve seats and the spark plug hole.

Anyway - Hope this helps

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