i have 3 letters for you

H...........E...........I!!!!!!


Its in and running great!! Man what a huge differance that made, I just cant get over it. I was surprised to see how much grinding had to be done, but it swapped in perfect and runs like it never had before. My questin for you guys that have doen this, what did your timing come out to?? also did you guys have trouble with the vauum line coming out of the dist coming really close to the fan. i had to put a fan spacer in so that when i turned it to get the timing right it wouldnt hit that little niplle coming out of the dist. did you guys run into anything like that? but all in all the carb is fixed and the hei is in and man i just cant stop smiling!!

 

Mines at about 10 degrees and I never bothered to hook up the vac advance, ran better without it

 

Glad to hear that your Jeep runs that much better!!

When I installed my Mallory dual point in place of my old prestolite, there was that much of a seat of the pants improvement also. Although I would like electronic ignition I waited to long and had to pay to much for my dual point in the long run to take it off for no apparent reason, so until it fails on me it stays there.
Back when I put my Mallory on, the internet was just kicking in and I did not know the difference and had never seen one of these old Jeeps with a HEI in it and that was long before Sparky's first site was up and running.

 

I had the same results. Yes the vacuum advance port is very close to the fan blade. IIRC my timing is 7 or 8 degees advanced to keep total advance within recomended limits for the engine. I installed the HEI when I had about 3,000 miles on the completely rebuilt engine. I have to raise the hood every day to be sure it is the same engine! I've never gotten so much bang for so little bucks. Other than some pesky minor oil leaks, I can't recall being so satisfied with and engine. (I say that with a free 231 staring anxiously through the outside of the grill in the garage. I'll burn for sure for making the dauntless look at a 231 for no reason at all.)

Anyway welcome to the HEI club, and don't forget to pinch yourself occasionally to be sure its real!

JK

 

you guys said you removed the vacuum advance?? i though that kept your timing right at higher rpm? do i need it??

 

The vacuum only *assists* the timing curve at high RPM's. Most people feel that the 2G carb doesn't supply enough vacuum to make much of an impact on the timing. Instead, the HEI has a mechanical advance - weights that move under rotation force as you rev the engine. Pull the vacuum advance hose, plug it with a golf tee, and drive around the block. If you can't tell any difference, leave it off.

 

Man that was fast! There is some unwritten rule in my garage that any new parts I get have to sit there for at least 6 months before anything is done with them. That took you what... maybe 3 days???

 

i have been wnating to do this for so long, i just was skeptical on th emoney to difference ration. when i saw you selling taht i jumped on it!! it would have been in a day earlier if the carbb wasnt acting up. carb was fixed weds night dist was in by noon on thurs. it went real good.

the other question i had is are you guys running bigger wires that 8mm, my buddy had a set of 9mm hei wires in his garage waiting to go intohis 74 w/ the msd upgrades, we "borrwed" these to try it out, is there a down side or bad effects to using the bigger wire?

 

they were free: brand new 9mm excell wires

 

I just went out and looked at mine,. It has been 12 years since I installed it. I kept the vaccuum advance and have a fan spacer so lots of room.

In dusting off the cobwebs from this old mind, I remember that when I first got it installed I found a kit with various colored advance springs, and played around with these until I was happy with the powerband the engine liked. I installed a Holly 390 CFM about the same time, so it was a summer in Reno of trying different combinations.

 

Eric: Glad you are happy with it. I was going to PM you and ask about any grinding on the man. or front intake bolt. The Cape Conversion "Kit" comes with a Torx bolt. A button head can also be used. Mine was put in by the PO and he just ground the stock bolt (going to be fun to get it off if I have to). Also, my HEI (I have no idea where he got it) has the vac port comming off the "Side" of the little canister and not the front. Wish I knew what the application for that was because it would solve a lot of problems. But, if you find a good FLAPS, they have a "formed" 90* vac fitting that should work fine.

On wires, I used a "universal" 8 cyl set of MSD "Superconductor" 8mm wires. I got the 8 cyl set because they were the same price as a 6 cyl set (just in case I screw up in making a wire). The MSD's are only 50 ohms/ft resistance. They 'taint cheap, but there worth it, IMHO.

Enjoy!

 

ohhh man.. I can't wait to do this to my motor

 

Vacuum advances are designed to enhance fuel effeciency at high vacuum/low load (cruise)conditions by pushing the advance curve farther forward . This advance dissapears under load(low vacuum) reducing the possability of detonation(ping). So an average engine will start with 5 Deg. advance. Mechanical adv will run out app 15 deg@ 2000RPM's. Vac adv 15 deg@17inches of vacuum. 5+15+15=35deg total advance while cruising.These numbers are a generalization, each engine/cam/intake combo will require different numbers. A good high performance machine shop can recurve your dist. to the proper spec's using a combination of different advance weights,springs,and adjustable vac. adv..A bad vacuum advance usualy costs one to two MPG in your hwy milage. As for where the direction the vac port points, all GM advances point straight out except HEI V6, which points up, providing clearence for the fan.

 

JD2000: That's interesting as that's how mine is, but it's the only one I've seen. I don't think I've heard from anyone on the board that has one. But then again, most stock vac. adv. are replaced with the adjustable unit for use on the :v6: , which is standard form. Mine prolly hasen't been changed but it runs fine with no detenotation at all on 87 oct. I have a digi dial back timing light so one of these days I'll have to check the advance.