I am replacing the mech tach in my 74. I'm going HEI and elect tach. Is there a particular year HEI dist I should get? What should I look for? Going to pick & Pull. TIA

Rick

 

Any HEI from a 262, 305, 350, or 454 will work. You need one with vacuum advance and without the 4-wire connector like the TPI Corvettes use. I don't think any year is particularly better. Most easy to find would probably be 75 to early 80s Monte Carlo, truck, or Caprice. I had an article in an old Circle Track that said the GM or NAPA modules are best, so you might look at that. If you can, get the big red power wire from the donor car. It needs to be used to replace the resistor wire from the firewall bulkhead. Good luck with it.

 

heres the wiring kit and instructions

http://www.madelectrical.com/catalog/hei-1.shtml

 

Thanks guys! As usual the forum comes through. The shop doing the rewiring is unimpressed w/unilite and stk dist. I'm having the tach redone and want as trouble free as possible. The HEI conversion seems like a natural upgrade. The dash was down so why not.

Rick

 

i have a 74 also and converted it to hei. i bought the kit from mad electrical too.

it is really a pretty easy upgrade. the info above is dead on. you are looking for a NON- computer unit. it will have a vacume advance canister on it and 3 wires coming out the side.

it can be from a small block or a big block, car or truck. i bought mine from ebay for $30 plus shipping. the best price i could find at a parts yard was $50.

you didnt ask for this, but it was the hardest part to me so i will just add it in case you need it... so the HEI only needs a single power line.
1. find the resistor wire, it is black with the pink words "resistor wire, do not cut".
2. cut the wire. no, seriously, I followed the resistor wire back to the fire wall connector and removed the connector from the fire wall.
3. "the trick" the wire connector is fused into the plastic box. so, get a soldering iron and hold it on the metal connector for a few seconds. this will heat up the plastic just enough for the metal connector to easily slide out of the plastic firewall connector.
4. insert the non resistor wire in to the same slot in the plastic box. and reconnect.

the kit from mad has the wire, the metal connectors and the special connections for the tach and power on the Hei.


good luck
john

 

It is not actually fused in there. It just seems that way. There is a tab to be bent back on the male spade connector, then you pull it out. You can re-use that one or buy a new one from NAPA, CarQuest etc. It is just a male type 56 connector.

 

If you want to retain your original mechanical tach but also want HEI ... please reference my ad in C3 parts http://forums.corvetteforum.com/show...52&forum_id=57
F/S: brand new tach drive HEI distributors $185

 

Which connector is it on the firewall? Would save me a lot of tracing...

 

It depends year to year, but it is the small pink wire that says "resistor wire-do not cut" on the outside. If you unbolt the engine harness from the bulkhead you should be able to find it.

 

pull the cap and check the advance weight mounting pins for wear. the one without the plastic bushings will need to be modified with a repair kit from the auto parts