<VV> best timing setting for a 140/4 with a 280 cam?

[BobHelt at aol.com]

In a message dated 7/4/2010 6:11:12 A.M. Mountain Standard Time,  
vairguy at echoes.net writes:

It's a  140 with most of the "step" machined out of the heads, forged rods 
and  pistons, and a 280 Isky cam.  I can advance the timing all the way to 
the  last mark (looks like 24 but I read the plate should only go up to 20?   
Maybe its a custom riveted on plate?) and not get any pinging.

This is  a street car but I'm looking for max power without totally killing 
my gas  mileage etc. as I put a lot of miles on it.  Where do you think I 
should  set my timing considering the 280 Cam and the fact that the car is a 
driver  for best performance?



Ray,
I'm sure that you know all of this but by machining the gasket step  you 
have somewhat increased the "fast burn" capability on your combustion  
chambers. AND that you should really ignore the timing scale on your engine by  1) 
using a good timing light with dialback, 2) blocking off the vacuum advance, 
 3) Reving your engine to 3000 rpm in neutral and setting the timing to 
about 36  degrees. Yenko used up to 40 degrees but I'd suggest 36 as a max. 
Chev's engine  test report indicated 33 deg was optimum for a stock 140 hp 
engine.
Regards,
Bob Helt