Porting - before or after valve job?

[rmchrgr]

You guys who port your own heads - do you get your valve job done before you start grinding? If so, why?

I might be answering my own question here because I am planning to get a set of heads cut for larger valves. But just for discussions' sake, I'd like to hear a general consensus on this particular subject.

BTW, I have two sets of 89-91 roller cam 308 heads and a set of MP porting templates.

Thanks,

- Greg

 

[Top Heavy]

Needs to be after in your case.......

If you are cutting for bigger valves, you'll be forced to grind more to match the bowl/throat into the larger valve seat.

Even if it were the same size there'd be additional work required after the new seats were installed.

 

[805moparkid]

yea ask them to also use the cutter deep so it makes it easier to blend and less work/material removed with the die grinder

 

[fishy68]

If you can, ask them to do the cut for the larger valves, take the heads home and do the porting then have the valve job done. I can guarantee if you do the valve job before porting you'll nick a seat (or 2 or 3) and have to have it/them re-done.

 

[OUTLAW]

Normally I would say before the valve job incase your grinder runs amuk but in your case I would get the seats cut then do the grinding then take it back to get the seats ground

 

[rmchrgr]

Cool, thanks for the info. Cutting the seats, then porting then valve job seems to make the most sense.