hey so i have a 305 that i put the lt1 cam in with new valve springs, i went carb after the swap. i was wondering if 18 to 20 degrees base timing is way to much, it runs good at 18 but doesnt feel peppy. a friend told me it was to much timing but the lower i go (14-16) the worse it feels.

for some setup info im running a holly 550 accel vac advance distributor, 19 hg on the vac guage, 13.8 at idle on the wide band, 14.2 at 40 mph. i feel that my air fuel is good and carb is tuned in well just wanted a second opinion on the timing. any thoughts would be appretiated.

thank, tyler

 

Imo if it likes that much initial and doesn't ping, run it. Mine liked/likes north of 12*, and I never had a problem with pinging so I ran that year round.

 

Yep - set timing where the car likes it - numbers are only for a reference to move up/down from. Set timing as high as you can without pinging at WOT - then back it down 2 degrees.

So, if you hear pinging at WOT at say 18, back it down to 17 - if no pinging there, then back off to 15. Just because you can't hear the pinging doesn't mean there's no detonation - thus the two degree "safety margin".

 

it pings at wot at 21 so i was was thinking that 18-19 was safe. thanks for the help

 

If you want to run 18-20deg initial timing at idle, you need to recurve the distributor.

You want a max of 34-36deg at max mechanical advance.

Shorten the mech advance curve to 16deg. (limit the travel)
typical stock is around 20-22deg. you want 16deg.


initial 20 deg base timing,,, total max mech 36deg
20+ 16 = 36


vacuum advance at cruise 10-12deg limit to 15deg max.