I personally used a Mallory unilite distributor, because on my truck a regular HEI distributor would not clear the firewall, without modifying the firewall. I know some people say they'lle work but in my own experience they just don't fit. This could vary from other years my truck is a '82. I also did some frame mods so the engine would sit lower, maybe this had something to do with it. The mallory outfit works great the 350 has been in my truck since 1985. I didn't do the original conversion but I have had the motor out numerous times (stupid tranny) and did the mods to lower the motor.