Rok_Stars_Bars

Ok, Im tryin to time my Cousin's 1968 C-10 Chevy 350. This is not the orginal engine (it was installed in the late 70's). From the Engine numbers it is 1970 350 with 1976 Low CR Heads (76cc) Assuming the Cam is stock. It was a points ingition but we converted it to the accel infared red thing. And put the matching Accel coil and wires. It was a 2bbl. We put a early 80's 4bbl aluminum intake. And a spreadbore adaptar to my 670cfm holley street avenger (and stuck a socket in the vac sec so it wont open). Now from what I read the intial timing is pose to be 10*-13*. With the engine at 650rpms, and the vacuum advance plug. It runs like total crap at 13*. It seem to run pretty darn good at 18*. Except at crusing and seem to cut in and out alittle.

Now the other day I advance the engine by ear (playing around). And we drove the truck and everything was perfect. Great power and everything. But when we got back, it was advanced to the point where the engine wouldnt start so of course we lowered back down.

Now something I noticed today, When I set the intial timing to 13*. Number 7 spark plug was arking to the header. So i wondering if I got some misfire goin on making it run like crap. The other day we did a Compression test. All cyd was 140-150psi except #8 it was 125psi (That was also on a cold engine, forget messing with the sparkplugs and headers on that hot engine). But while we had the spark plugs off. We played around and gap them to .050. The Spark plugs were good color too.

Input please or suggestions

Damon

Do the vacuum and centrifugal advance mechanisms function properly in the distributor? If the timing isn't advancing like it should (rusted/seized/gummed up advance mechanisms) it will want tons of initial timing to feel like it's got any power when you're out driving it around. Followed, of course, by difficult hot starting from the high levels of initial advance trying to "kick back" against the starter.

If you had/have an arcing plug wire, obviously you need to replace that and the plug it goes to if it's fouled out before you do any further tuning or diagnosis. Replacing all of them on general principle is also a good idea if they are old or give any indication of being in poor condition.

That's where I'd start. Converting an old points-style ignition to mag/opti pickup is a good idea but it doesn't affect the condition of the advance mechanisms.

Rok_Stars_Bars

Thanks alot. Well, this is exactly the route I plan on goin. I just needed someone else to tell me LOL. We have alrdy converted the points to the opti pickup. And the wires are only 3 months olds they are Accel High Temp wires. Reason why I added in the post we regapped the plugs, maybe it is gap too much.