HEI: Ignition box or ignition module

[americanmusc1e]

is an ignition box such as a MSD 6AL much better than a MSD ignition module???

OK my 388 does fine, but it doesn't want to rev past about 4500, I think its an ignition related misfire. (the valvetrain is the same from my old 355 except for a larger cam, and my 355 was fine up to about 5500rpm)

I'm running a stock HEI and I need to upgrade. What is the best way to upgrade my HEI on a budget?????

what about this?????? http://www.summitracing.com/parts/SUM-850030/

[mr48chev]

That set sure isn't going to hurt if the truck needs a good tuneup but I'd be checking the advance setup in the distributor as it stands before doing any serious upgrades. In other words, Is everything in the distributor working correctly now?
If you put a light on it will the distributor advance the way it should when it should?
I am one of those who can't see the point of going too wild or exotic on ignition for a street motor that you intend to drive and cruise with as there is usually a trade off for that wide open throttle performance that those systems give.

[ll____b0t____ll]

i was having a similer problem just the last 2 days and it turned out that i had 2 spark plugs that while not bad just had a weakness and coupled with my timing being set just a hair out of fase i had the same issue. A new set of good plugs and some distrubutor tuning worked that right out.
Not saying thats your problem but ide look there before going 6Al.

[mclairmo]

An MSD box won't solve any problems. Be sure everything else is 100% first. Check timing, plugs, cap, rotor, wires, filters, etc. Sounds like maybe with the larger cam but the old valvetrain you are experiencing coil spring bind. Make sure those coils can handle the increased lift without binding. Also, a good condition stock HEI should be fine up to 5,000 or 5,500 rpm. Also, I would not want to keep my engine up that high anyway. I like to baby my engines so they will a live a long and happy life. Good luck.

[americanmusc1e]

Originally Posted by mclairmo

An MSD box won't solve any problems. Be sure everything else is 100% first. Check timing, plugs, cap, rotor, wires, filters, etc. Sounds like maybe with the larger cam but the old valvetrain you are experiencing coil spring bind. Make sure those coils can handle the increased lift without binding. Also, a good condition stock HEI should be fine up to 5,000 or 5,500 rpm. Also, I would not want to keep my engine up that high anyway. I like to baby my engines so they will a live a long and happy life. Good luck.

instead of "coil spring bind" i think you mean valve float,

I'm running Comp cams 981-16 Valvesprings. the first cam was a Comp HE 260 and the new one is a Comp XE 268. I think that these springs are compatible with the cam I am using, but I will call Comp tommorrow to make sure.

hopefully it's not the spark plugs, I'm running AC Professional series and they're $6 apeice

the weakest link is the cap and rotor--they came with the dizzy when I bought it used

the next weakest link is the timing itself-- I'm not sure what the total timing is

[mclairmo]

Coil Bind is when the coils stack solidly during valve lift. The following is from the Comp Cams website. "Once the valve springs have been installed, it is important to check for coil bind. This means that when the valve is fully open there must be a minimum of .060" clearance between the coils of both the inner and outer springs. If this clearance does not exist, you must change either the retainer or the valve to gain more installed height, or change to a spring that will accommodate more lift or machine the spring seat for extra depth."