Ignition timing and cam Question,the good stuff

[benw88]

Hello everyone,

I have a 68 c10 swb with a sbc 350 with a muncie 4-spd shiften the gears. I have built this truck since I was 15, now in my old age at 20 I have realized some mistakes I made along the way.

The motor is a 70 year, edelbrock performer intake, edelbrock electric choke carb 600cfm, headers, MSD HEI street fire dizzy, dual electric fan, roller rockers, comp cam XE274H .

Cam specs: See attachment.

I am trying to learn how to properly tune my motor because it is currently not running good. I recently realized that I cant just slap components together without any plan and expect them to work:spank:. I am skilled mechanic and also going to school for mechanical engineering but I don't know if there is a huge problem with the current combination of components I am running.

1 st. I need to determine if the combination of carb, intake, cam, and Dizzy will work.

2 nd. How do I properly adjust my timing with setting the proper timing curve, advance, with the cam I have what full mechanical advance should I have and what advance at idle, and vacuum advance. Do I need a hotter coil or different dizzy?

3rd. How do I properly tune the carb. I have attempted jetting the carb numerous times but I feel that I need to figure my ignition out first.

I also pulled and resealed my intake manifold to make sure I don't have a vacuum leak. replaced the sparkplug wires, added the heat protection sleeves near the header to save the boots from shorting out. I also wired my dizzy through a relay so it has straight battery power.

Please excuse my terrible spelling I immigrated to CA from Germany in 07

Any suggestions or tips are already greatly appreciated.

-Ben

[adricar1]

i am sure you will have many answers to the questions you are asking, however i would start with setting the timing to 12-14 degrees static and have advance on the distributer of 22 degrees max . this needs to be all in by 3000rpm.without the vac advance connected.this giving 36 degrees advance.

the set up you have will work , re the carb just read the edelbrock manual , and i would imgine the factory jetting will be ok out of the box.i have dynoed many engines with the carb you have and 99% of the time for a not radical engine has been right on the money as far as fuel settings are

good luck.

[benw88]

Originally Posted by adricar1

i am sure you will have many answers to the questions you are asking, however i would start with setting the timing to 12-14 degrees static and have advance on the distributer of 22 degrees max . this needs to be all in by 3000rpm.without the vac advance connected.this giving 36 degrees advance.

the set up you have will work , re the carb just read the edelbrock manual , and i would imgine the factory jetting will be ok out of the box.i have dynoed many engines with the carb you have and 99% of the time for a not radical engine has been right on the money as far as fuel settings are

good luck.

Do you know what the factory settings are for the carb, mine definitely is int at this point.

Do you think the cam is to big or okay?

[adricar1]

carb settings are available from edelbrock on there web site.
re the cam it all depends on the application, i have used the same in a 55 chevy , with a 350 and alloy heads, it lights up the rear tyres.a liitle lumpy, thougth
the manifold i would change to a rpm type.

[turbotruck]

simple way. lock out distributor. put timing at 36 degrees. remove edelbrock, throw in trash. install holley. install wideband. tune holley using the afr as a reference

[Mike C]

I'm a Holley guy because they are so simple, but with that said, I have 3 Edelbrock carbs and they can be tuned to be as effective with some time. The wide band O2 a great idea, but not mandatory.

What cylinder heads do you have? How much compression? What converter and rear gear are in the truck? These things all have a bearing on how much advance you might need or the motor can tolerate.

Do you have a way of checking total timing and RPM? A dial-back timing light is the best tool but you can do same with a harmonic balancer tape.

Do you have the paperwork on the MSD distributor? It will tell you what springs, weights, and advance bushing were installed on the distributor for a baseline.

Honestly, buying a book on Carbs and another on Distributor ignitions will be worth more than the cost and educate you much faster and more accurately than message boards.