'70 340 ignition timing with Comp cam?

-
A

Airfix

Well-Known Member
Joined
Jan 26, 2008
Messages
111
Reaction score
0
Location
Cloverdale BC Canada
1970 340 10.5 CR, all stock except for Comp Cams .470 lift, 270 deg duration, any body runningthis combo already, how about ignition timing?
Just started my engine for the first time after rebuild, with static timing set a 5 deg BTDC, what works on yours? I won't be driving for about another 6 weeks but would like to get close to a good setting before.
Thanks.
 
What dist. do you have? If it's just a stock dist. unless it's modified to reduce the amount of advance you probably can't go over 8-10 degrees or your total timing will be too high and detonate at high rpm. If it is modified or adjustable I'd probably go with about 14 initial and 33-34 total as a start and tune from there. If your not a distributor guru and want it set up by a professional call Don at FBO and tell him your combo and he can set one up for you.

Here's his website url

http://www.4secondsflat.com/
 
5 is definitely not enough. SB Mopes, especially with a camshaft, tend to like initial lead.

I'd start at 14* and keep cranking it in until it kicks back on the starter or it runs on when shut off. Then you know the max amount of initial.

You'll definitely have to limit the advance in your distributor.

Once you get your timing down, the carb will be MUCH easier to tune.
 
With my basically stock 68 340 I run 34* total (initial+mechanical.... vacuum plugged) with a MP electronic ignition.
 
I have a stock 340. Have not tryed the total adv thing yet but it does not like more than 6-8 int or so. That is with a stock cam and 10.5 CR. I think you may be able to get away with a little more with the bigger cam you have.
 
You must log in or register to reply here.
-

Back
Top