hei distributor

[mjck5]

i am planning on swapping out my stock 86 distributor with new hei, i see them at 6500rpm 7500rpm and 9000rpm, hoping someone could tell me what the difference is in the performance, its going in a 400sb with rv cam so not a race car

 

[Ricko1966]

i am planning on swapping out my stock 86 distributor with new hei, i see them at 6500rpm 7500rpm and 9000rpm, hoping someone could tell me what the difference is in the performance, its going in a 400sb with rv cam so not a race car

Why are you changing your distributor? And what brands and price range distributors are you looking at?

 

[mjck5]

its the stock distributor and i got rid of all the esc stuff, when i changed the cap and rotor it was pretty rusty and nasty looking inside, i was looking at a mas distributor online i think it was 60 or 70 bucks, im just not sure what the difference is in the rpm ranges

 

[Buck69]

A distributor is not something I would pinch money on. Losing spark is one thing, but a failure under the manifold can get costly real quick.
Have you looked at their reviews?

 

[ali_c20]

Get a quality stock style distributor like proform gm licensed or DUI with mechanical and vacuum advance and match the gear material to your cam (roller/flat tapped). On the cheap distributors modules and transistors like to die soon.

 

[Ricko1966]

its the stock distributor and i got rid of all the esc stuff, when i changed the cap and rotor it was pretty rusty and nasty looking inside, i was looking at a mas distributor online i think it was 60 or 70 bucks, im just not sure what the difference is in the rpm ranges

I wouldn't buy a 60 or 70 dollar distributor the rpm ranges for your needs are not a concern. I'm busy back in an hour or so

 

[mjck5]

whats a good recommendation that wont break the bank

 

[Ricko1966]

If your hei you have is in good shape,keep it,clean it,lube it,recurve it and change the coil if you plan on spinning it past 5500 on any kind of regularity. A cheap universal hei replacement distributor isn't going to be much if any advantage over a stock HEI and probably not as good in the long run. If you buy a cheap HEI performance distributor you are probably going to end up having to recurve it anyway. The cheap one size fits all HEIs have such a lazy curve,so they don't cause detonation. So if yours works learn how to recurve it and dial it in. The GM hei is an excellent piece they still run them on the ZZ engines. MSD would be my other choice. But in a mild street build spend the money on something that really makes a difference.

 

[ali_c20]

I run a DUI since 2015 and it's real good quality. Friends running the Proform Gm licensed ones since years without any problems. MSD.

 

[Octane]

I run a Streetfire.About $180 eight or so years ago.Still running strong.

 

[Randy and Easton]

We did a basic HEI from Jegs in 2021 when he got the truck and its been fine ever since.

JEGS 40002: HEI Distributor For Small Block & Big Block Chevy - JEGS

JEGS HEI Distributor

www.jegs.com

 

[Ricko1966]

Now all of you running universal replacements. How many of you have recurve them yet? You should to see how much performance and milage you are leaving on the table. Last week this forumn,different thread,just lighter springs made one of our members happy as a clam. He wasn't unhappy to begin with,and didn't realize the distributor was where he needed to start. Dialing something in,it's total,then curve,then move to carbureation.

 

[Randy and Easton]

Now all of you running universal replacements. How many of you have recurve them yet? You should to see how much performance and milage you are leaving on the table. Last week this forumn,different thread,just lighter springs made one of our members happy as a clam. He wasn't unhappy to begin with,and didn't realize the distributor was where he needed to start. Dialing something in,it's total,then curve,then move to carbureation.

We are going to look up that thread. Not sure we are smart enough but to nudge the gas mileage would be a good move. Thanks @Ricko1966

Randy and E

 

[Ricko1966]

We are going to look up that thread. Not sure we are smart enough but to nudge the gas mileage would be a good move. Thanks @Ricko1966

Randy and E

That thread won't do you as much good as you need. That on was thoughts on low vacuum poster @luna negra it's still worth reading. If you want to look up threads,look for the ones where I was helping @Squirrely Brother dial in his timing. Take off your vacuum advance hose. Back your timing down to like 30 total. Now find an area with 2 landmarks you can accelerate most of he way through 2nd. Now measure your speed, not your time at the end of that distance. Now start bumping the timing 2 degrees at a time and measuring that speed at the 2nd landmark. When your speed starts dropping backup to your best speed,then back down 2* for safety. Now start swapping springs going lighter find detonation then go back next stiffer. Now check your total. If you have working egr subtract total from 50,add that number back in with vacuum advance. If you don't have working egr subtract total from 46 and add in that number. There's more too it than that.But if you get to this point without any drivabilty problems the rest is just fine tuning. If you start getting detonation from the vacuum advance we need to play with what hg. vacuum the can comes in at.
I recommended a particular advance kit in the thread with Luna negra,it's a crane kit that has all you need and okay instructions,I do not like their method of finding best total,it's not as accurate. Anyway he only changed springs and was happy because he couldn't find the kit. And I didn't write him all these directions assuming he'd find the kit,and follow theirs.

 

[Ricko1966]

I'm going to explain something a lot if people don't understand,your engine wants 45-55 degrees of advance at cruise for maximum mpg,it wants a total of 28-38 degrees of advance for maximum acceleration. Now these are imaginary numbers and exaggerated to make the differences more obvious. So your whatever distributor you chose has 20 degrees of centrifugal advance and the springs in it allow this advance at 3000 rpm. You set your timing at 14 degrees,now you've got 34 degrees at 3000 rpm and up you'll probably accelerate good. Now your whatever distributor adds 10 degrees vacuum advance so add that to your 34,now you've got 44. Mmm close enough you aren't going to complain. Here's the fun part,say your cruising speed is 2000 rpms,well now you're centrifugal advance has fallen out,you aren't even close to what you need for mpg. Performance? No problem you're going to mash the pedal,downshift and just like magic you have 34 degrees of timing again for good performance,so everything's great,but you get crappy milage. Because you never tried, you never realized you were leaving performance and mpg on the table. I didn't know how to write this so I'm adding it here. On that same scenario as above if just your springs were lighter allowing full advance at 2000 instead of 3000 you'd have been so much closer to the sweet spot, and getting in the sweet spot is just a few.more tweaks from being there. The average off the shelf distributor is going to be way to conservative,so they don't get detonation complaints and swamped tech lines teaching everyone how to tune.