PV timing?

[Fred1956]

I'm back... I got the silencer cleaned and repacked, thanks Glenn!, and now I'm on to the next problem(?)
I changed my 250 to a 274 not long ago and while it runs great and I have no power complaints, jetting is very strange and I'm having trouble wrapping my head around it- MJ 160, PJ 35, AS 1 3/4 out needle JD red in middle clip. Engine will idle forever, good power throughout the range & WOT plug chops are darker than tan but not as black as they were with a 170MJ. At the last HS it got ran WO a bunch as we had several long straights that were WO in 6th for 20-30 seconds (gearing is 13/51). I called Ron at RB Designs, he did my carb, and he wondered about PV timing thinking it could be mimicking a rich condition. I have no service manual and my search on this site finds no reference to timing the PV. Does it need timed? Or just adjustable slack? & shims behind the spring?
Given others' issues with jetting I guess I should just be happy and move on but just the thought of a 160 when everyone else I way bigger makes me a little nervous. Any ideas? Thanks

 

[Dude]

Aproximately 0,1 mm shim are 100 rpm; 0,2 200 rpm ; 05 500 rpm. So if you install a 0,1 mm shim your valve opens 100 rpm later. If you remove 0,1 mm shim your valve opens 100 rpm earlier.

 

[Fred1956]

Aproximately 0,1 mm shim are 100 rpm; 0,2 200 rpm ; 05 500 rpm. So if you install a 0,1 mm shim your valve opens 100 rpm later. If you remove 0,1 mm shim your valve opens 100 rpm earlier.

Thanks but Does it need timed?

 

[Dude]

Plugs dont lie. I guess i am wondering what the real ? is. Are you just concerned your jetting is not the same as others and you think its to lean but the plug says otherwise?

Go back to the beginning and jet it rich as hell to it starts to stumble and then go back till it runs better. Then check plugs. Get a wb02 or a egt as well if your real concerned.

you doing wot chops and only wot pulls before you chop?

Also if you have had ron do the carb and the head, things are going to be running more efficient and require less fuel. I would just do a few wot chops and be leave it.