mustangs killer

I was wondering the potietial gm's old hei distribitors . is it causeing probs in my 400hp 355. is the spark dead at 6500. if it is not suffecent then what should i do about it. who makes a good coil kit for them and what voltage do i need to pull good at 6500. thanks

Hurtin4Hp

I am running the GM HEI distributor and on the dyno last week my HP was falling off sharply at about 5300RPM. I put a new coil on the distributor but it did not help. Also, the number 2 spark plug(which has the longest wire) had some black on the insulator, whereas the others were clean. We still think it is an ignition problem so I ordered an MSD box and will install it this week. 10.7:1 compression and the problem was capping my HP at about 420.

mustangs killer

my motor is running about 10.5:1 compression and a stock gm distribotor. i want to up grade the distribtion but i don't want to spend 250-300 to do so. i want to stay in the 100 dollar range. I am hesitant to buy an aftermarket coil because i ' am not sure if the 48,000 or the 54,000 volts coils will really help my performance after 5,500RPM's and my max HP does not hit until around 6300-6500. Also would a recuve kit help.

[This message has been edited by mustangs killer (edited February 15, 2001).]

84FTA

When you get into higher RPMS that is where 'mechanical' distributors die off. Some places sell better modules to help fight this problem off but they are mostly a waste because of the design. (Many small "triggers" flying around a very small circile). If you were to up grade to a crank trigger ignition or full digitial ignition your problem would be solved

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1984 WS6 Trans Am Hartop
Former L69 Car under restoration
1984 Trans Am T-tops
4-bolt main 350, performer intake, headers, Holley 650, T-5, hayes clutch, dual elec. fans and 3.23's.
Daily driver and restoration
13.98 @ 101

The ODB

Under ideal conditions HEI's can perform great on a modified engine. Unfortunately conditions are rarely ideal.
Invest the money for a good distributor and matching coil. It will save you a lot of trouble and wondering in the future. The ignition is not a good place to save money on a high rpm engine.

good luck,
ODB

Demon Z28

Anyone ever thought of getting that High Energy Spark Module from MSD? good for a strong spark up to 9000 RPM I'm redoing my HEI right now with their racing rotor, cap, the module and a new performance coil about $170 worth of parts from summit, will outperform a 6A box

JoelOl75

I don't believe an inductive discharge can outperform a cd box... Maybe in low rpm spark duration (where cd's lag requiring multi strikes to compensate) But the shear energy of over 500v going through the primaries on the coil has to be better than any 12v system.

'67stock

Also wires are real important. Most wires can only flow 30 something thousand volts at least so I heard.

About the hei i'd decide what you want. sell it or keep it. if you keep it i'd throw a big fat coil on it or even spend $100 on a quality rebuild kit. Get a jeg's catalog they got a couple in there. I hate to say this but accel's brute thunder looks like a good coil. Any coil you do get for an HEI should either come with a low resistance bushing or recommend getting one with their coil. If they don't then it's an inferior coil. I don't remember the exact story but the good coils will fry the cap from heat without one.

Add a good high performance module too. I was just looking at the catalog and the Holly annihilator looks good. It bypasses the HEI module but you might want a good coil on top of it. The Holly runs at $170 has a rev limiter too. You could also just get a Pertronix Tune up kit for $120 for a chevy hei. New cap, rotor, weights, their coil and module, springs, and adjustable vac advance. What ever you do though don't get Proform's HEI!

You got alot of choices that are supposed to work. MSD makes a module for $66 that's "capable" to go to 9000rpm. As long as you also got a good coil too I'm sure. You could also spend $400 on an MSD crank trigger(maybe more not sure though) but the crank trigger's nice! Or you could get an MSD HEI kit for $190 or $288 for their 6 series. Or you could go with a mallory hyfire or you could throw your cash down the drain for Jacobs. Or you could ditch the HEI for a regular distributor but I wouldn't. That's what I run but not to 6500 yet, still got some mods to do before I get to there. I have a Mallory unilite distributor and coil sittin in the garage. It needs a new cap and rotor probly but the only reason why it's out there is I don't have the clips for the cap. I'm willing to sell it if you want.

I did recurve my HEI but I didn't really notice a difference besides how much or less I (turn the dis) to get to the same spot. I think it's probly more for setting when the full advance comes in. But the Crane cams adjustable vacuum advance comes with springs as well. If you got a lopey cam I'd suggest the adjustable vac advance. Some things to think about. There's too many choices out there actually IMHO to decide on so just go with one and try it out. Personally I'd probly give holly a call about their annihilator and see if you need a good coil to go with it or not.


Also I wanted to add that a buddy of mine used to run a small block to 7500 max once on a mallory unilite and coil. We could get it up to 6500 no prob it was fun. I miss puttin my life in the highways hands and those cars come up so quick when your runnin over 150. The only problem we had with it is usually one plug would come undone but now they got a better cap out to keep the plugs connected.
Enjoy.

[This message has been edited by '67stock (edited February 16, 2001).]