On a mildly built 390, stock or performer intake, 700-750 cfm carb, stock heads, mild cam and headers, basic build is it worth the expense/time of an aftermarket or ds2 ignition? Will the stock dizzy with a petronix or simmilar be enough? Thanks, Matt.

 

Pertronix works great on mine.

 

JMO, but I would say just get the Petronix kit(the number 2 kit is better then the original) and have your stock dizzy set-up for when ever you want full advance to come in. I think stock is like 4500 or 5000. I had mine redone to come in full advance around 3000. I have more done to my motor then what you are discribing and I don't think I need the MSD or other ignition's.

 

Thanks for the replies, I'll stick to the stock dizzy and have it recurved when I swap to a 390.

 

Have it recurved? Let me know when you find someone to do that!

 

My local parts shop did mine. $40 with spring replacement. They do engine builds and sell aftermarket part's. You can do it yourself if you want to mess with it. You just have to change the spring's and/or weights in the dizzy. It is under the top plate, below the points. To complicated for me. Chevy's are wasy, but Ford's are a little more difficult. ( I think that is true with everything on a Ford...LOL )

 

To have a dizzy spun or "recurved" by a shop on a Sun machine would be under the standard specs in the machines files, a general spec.
Note: no two motors are the same even if they are built by the same shop as each motor will require a different advance curve and when for maximum results.
Back in 73 I wasted my money ($27.50) to have a dizzy spun up, what a POS on how it ran after. Later years I had a Sun dizzy machine but sold it, takes longer but you can tune an ignition system better by testing with notes.
There are too many variables like compression, cam, carb, intake type, thermostat, gearing, air temp, grains moisture, load pulled, altitude and how it is driven aka like lead foot.
With the old style vacuum advance unit which is now banned by EPA (old ones can be rebuilt by a company I found in Oz), you can adjust the limit plus when it happens.
Just because it's new doesn't mean it's better.

 

They told me when I had my dizzy recurved not to use the vacuum advance. Like Beemer said every engine is different so just check to see what they tell you.

 

For a street motor you want vacuum advance plus don't take it as the final word on what they tell you as many are wrong about FE's.

Hell just go with a magneto.

 

I use a shop out of denver called Blue Oval Performance. Rob is an fe guru, at one point I think he was on the forums here but not sure of his username or if he still pops in. Matt.

 

I tried it with the vacuum advance hooked up and it spark knocked like mad.

 

I'm beginning to think that I just don't have the brain required for dizzy curving. It just don't make sense to me. I'll sell 100 dollars to anyone who knows what they're doing and will come out to NE Ga and give me a hand.

 

Geez , I don't know. I converted my original '65 to DS2 and bought a re-curve kit from...Mr Gasket? Can't remember, but it works fantastic and was really easy to do both the coversion and re-curve. May not be as optimal as having it re-curved on a machine, but works a ton better than it did. Best part, I don't have to jack w/ points ever again!!!

 

Read reply number seven, what are you smoking with your reply PROSTOCK?
A machine will set a dizzy within the the general advance specs for a standard manufactured Ford engine, if this general standard is good enough
and your happy so be it, this is sad.
Just because you or a shop set a dizzy per book spec doesn't mean it's correct unless you had some dyno time and by this not a instant maximum hp number but a motor that will pull a grade with a load at maximum performance without eating itself up.

 

Lighten up francis! Put down the crack pipe....

Read the first 4 words of the post "On a mildly built 390", he's not looking to eek out every last tenth of a HP. He just wants to know what ignition we suggest. My response was what I had done, and installing the spring kit in my distributor did make a noticable improvement. I never said I set it to any prescribed "specs", I did tune it to my application though, which is why I bought the kit. I am happy with my results and that is not sad. I can get 13 HWY MPG in a '65 F250 w/ a 352 C6, stock single exhaust and 3:73 gears. I also have no issues pulling a 8,000 trailer/tractor combo on 87 octane cheap gas. It's been going for 50,000 miles this way without "eating itself up", even on 100°+ days, so I think I pretty much have it right.