Hello all, working my way towards completing my 383, bored .30, purple cam, p&p 906 heads, flat tops, built to run nitrous, but have not chosen carb yet, not sure if I should do dual quads or single 4, but my question now would be how do I figure out what ignition to go with? I need to set up the whole system, thanks for your help!

 

79 -

Every body has opinions, so here's mine ...

Twin carbs look cool, but a single 4V is just easier to deal with. Depending of the specs of the cam (sorry, never used Mopar cams), anywhere between a 750 and 850 double pumper will be in order.

As for the ignition system, hard to beat the Mopar Electionic rigs. I like the old school orange box, but the silver or gold boxes may ne in order, depending on how much real racing you plan on doing. They have kits with the box, distributor, resisters, harness etc. MSD might give a slight edge in race conditions. but for street use, after 30 years, I'm still not convinced.

Archer

 

Yep, Mopar EI. Can't beat it unless you got MSD really..

I just had stock electronic ignition on mine with the orange box, but my tach started going out of wack..

So i ended up getting a used MSD box and it fixed it. Didn't really notice a big difference in performance though.

Left the orange box on just in case..

 

Thanks, I will look into it. Btw, someone should boot that pos who posted an ad in here...

 

So is the only reason I should go with a single set up is because its easier? Isn't there alot of gain out of a dual quad set up? Especially for a built motor at that... I am semi newb with carb's but from what I have gathered I expected it to be a pretty substaintial upgrade. If anyone has other information please let me know...

 

69 -

Ah, no. Engines produce power based on flow dynamics. Nothing else. If you think getting more air and fuel into the cylinders, you're only half right. The cylinders need a way of accepting the A/F mixture - that means valve size and cam specs. It also needs a way letting the stuff out, again valve size and exhaust pressure (resistance from headers, pipes, mufflers, etc). OK, there's more to it than that, but it's a start.

If your cam is working optimally on a 750 or 800 cfm single 4V, going to a 2x600 cfm will net you 1200 cfm. Will that work? Sure, but it's no longer optimal. Drop down in carb size to the same cfm as the single and what are you gaining? Ziltch, except the head ache of keep the two carbs in sync A/F mixture and linkage wise.

Long story short, unless you're running a full race rig that will handle (or need) the added cfm, all you're doing is going for looks (and that alone isn't a bad thing), IMHO. But, it's your car and your call.

Archer

 

what he said, in his last post,


but i use msd,ignition,

 

blue -

Just curious, how would you switch from the MSD to the Mopar box, if you had to??? The Mopar box has the harness and the MSD is straight wire, isn't it?

I thought they made an MSD with the Mopar harness connector in the past, but can find a reference for it.

Archer

 

msd give you jumper wires to wire it back to factory ignition, so they did with my 6al sum 12 yrs ago.

 

Bob -

Cool, thanks.

Archer