Engine Hei Distributor On 5.0

Discussion in 'Fox 5.0 Mustang Tech' started by 65-Fstbk, Feb 14, 2014.

  1. Hey Guys,

    I'm building a motor for a 65 Fastback. Using a 1987 5.0HO block as the foundation but it's going to be carb'd not FI. I'm using a Weiand Stealth dual plane manifold and a comp cam 35-440-8. T5 trans with a basic 480-500cfm carb.

    My question is..are any of you running HEI distributors? I bought one for my build but have since read a comment saying that HEI is not great for motors where performance on the bottom end (below 2500rpm) is also required.

    Not sure if that's accurate or not. Does anyone have any experience with HEI on the 5.0HO?

    Thanks in advance.

  2. First I will start by saying that a 500 cfm carburetor is a far bigger concern of mine than an hei distributor. As far as the hei distributor goes, I don't suspect you will have any problems. Similar type distributors were used on other brand cars from the factory operating under the same premise and with zero performance issues. I personally don't like the look of an hei on a ford as there is too much going on with the coil mounted in the cap but that is just me. performance wise however you will be just fine.
  3. Thanks for the reply. I agree with you and in fact if I didn't have the HEI already I think I might go Pertronix. I have it now so I'm think of using it for the time being and will changeover once all the other small things are ironed out. As a matter of fact I'm one of those folks that can't stand guys putting chevy motors in ford cars yet here I am with an HEI.....8^O.

    The carb size is always a huge debate which I have also struggled with. After reading way too many articles and posts etc on the subject I found what I thought to be a common denominator. That is that most people tend to think the bigger the carb the better. That might be good on a high rpm race engine where the motor is gulping in lots of fuel under high load, but for a good street motor that's not required. Most people overcarb street motors and the power suffers at low end which, on the street, is where it all happens. I haven't bought my carb yet so if anyone has some good arguments otherwise I'm all ears....or eyes I guess.
  4. I have in years past seen great results with a 600-650 cfm carb on these exact motors with stock e7 heads and a cam. You are right, too big of a carb and you loose intake velocity and the atomization of the fuel suffers thus decreasing performance. I think you are on the small side of things at 500 cfm with the carb. In the last few years, since having an in house chassis dyno, we have done a lot of playing around with this kind of stuff and I can support this statement with dyno proven results.

    And for the record, tisk tisk on chevy parts in your beautiful ford, lol
    A5literMan likes this.
  5. That matches what I have heard: multiply the number of cubic inch engine displacement by 2 and that is the best CFM for the carb size.
  6. Thanks guys, much appreciated. I have no problem going to a 600-650 cfm carb so that should be good. Hopefully the Ford purists can find some forgiveness for the temporary HEI.
  7. Not a bunch of haters in here. Just enthusiasts! Post some pictures if you have some. We all love pictures!
  8. I am also am Olds person, I run HEI instead of a stock ignition, and I would never switch back to points or to an MSD, unless I was going to spin past 6500 rpm. The limit on a stock type ignition is dwell time to charge the coil. That is why they have coil on plug ignitions now. There is eight times the coil charge time over the single coil. The capacitive discharge systems do not produce a long enough spark at low rpm's to burn all the fuel. Hence the multiple sparks at low rpm's in the MSD name. So the stock style ignitions will give you better performance at low rpm's.

    The simplicity of the HEI is really attractive when you are ditching the stock set up. Especially on a Dodge. It is reliable and parts are available for cheap even at tractor supply places.

    A vac. secondary 600 cfm carb will serve nicely. My E7 long block with a performer egr manifold got better mpg than my newer efi car and was fun to drive.
  9. I'll post some motor build pics as I start building it. here's the front end when I was prepping to spray the engine bay. Before and after. The whole front end is new including disc brake conversion, quick ratio steering box, upper control arms dropped 1" like Carroll Shelby used to do on the early GT-350's, 1" sway bar, 620 coils, everything new or rebuilt. Resize Front View.jpg Resize POR-15.jpg Resize In booth.jpg Resize Done.jpg Resize POR-15.jpg Resize In booth.jpg
  10. :nice: Have a blast!
  11. Cool project and nice work!
  12. I used to have a HEI on my 302 from DUI. It worked great but I decided to get rid of it because it was too big.
  13. Too big is relative in this case. No coil on the fender or intake and a lot less wiring around the engine compartment are big bonuses. And it is not like a 5.0 has a small diameter cap anyway.

    I hope we get to see more of this project.
  14. It was big to the point where it would hit the heater hose connection while adjusting it. I decided to remove the heater hose at the time but now I am going to put them back in on this rebuild so I sold the distributor.

    It definitely simplify 's wiring though and worked great!
  15. I wonder, do they clear strut tower braces?