Looking to upgrade to a new HEI, i still have the original in my 78Z, it has many miles on it.
What would you choose?
Also going with new wires, and a new alternator.
Thanks.

Proform has what seems to be a good unit that comes complete with 50,000 volt coil, low saturation module, hi-po ignition curve, cap, & rotor. Sells through Jegs for $156.99. Personally, I like MSD but I don't think I've gotten my money's worth with it. Unless you are running N2O, or turbo/super charged, a good stand alone unit will serve you well.

if it's a stock car just leave it alone, unless it's broke. don't buy a "high voltage" coil unless you are prepared to do highway driving exclusively. a high voltage coil must reduce spark duration and current equally. the problem with the high voltage coils is at idle and normal crusing rpms, the plugs need a long duration fire as well as a solid punch of current to burn off the contaminants. you'll end up with either misfires, prematurely fouled plugs, and poor gas mileage. it is current, not spark voltage that ignites fuel. grasmo.

I'm not buying the "exclusive highway driving" scenario-true, you don't need a HI-PO HEI for your motor but swapping out for a nice, low resistance set of wires should really help. I would just buy a nice parts store replacement coil and go with a set of Taylor spiro-pro wires-should be around $45-55 bucks in your area I would guess. For a stock motor, you don't need anything else. -Jabin

I have the MSD HEI Conversion & think it was well worth the money. There was a definite difference after installation from start-up to idle quality to driveability.

Thanks for the tips.
My main concern is that since its a high milage HEI that there might be shaft end play, or something else wore out on it.
The engine is mild 355, but stronger than stock.

I really like my proform HEI, but Im going to order a MSD digital madule with rev limiter to go under the cap someday.

If it is a high mileage unit, take it to a shop & have them check it out.Better sale.

i bought a summit brand, runs like a champ!