EFI help needed - coolant lines

I used a 5/8 to 3/4 adapter fitting on the lower heater core fitting to match it to the 3/4 end of the heater pipes on the EFI setup. I did have to remove the heater assy and mount it as close as possible to the heater core, which means it is mostly on the interior side of the firewall. It would make life a lot easier to find a molded hose to fit the location, since it is a really short run and difficult to get the 3/4 hose on.

I used to have the heater lines running directly to the 5.0L steel lines on my '66. The rubber hose was a pain to get on because of how close to the firewall they were, and the fact that one of the steel hoses is larger in diameter.
After about 6 years in this configuration, I ended up blowing the heater core (guess I revved it to high too many times) and spilling that foul smelling green liquid on my carpet.
When I changed the core, I cut the two steel lines shorter, past the original location of the bracket that mounts to the intake manifold. I welded the bracket back on in a new location. This lets me use longer rubber hoses, and still retain the water temp sensor and EGR cooling line.

I welded up the holes and don't have a heater for the time being.

jmenke said:

I used to have the heater lines running directly to the 5.0L steel lines on my '66. The rubber hose was a pain to get on because of how close to the firewall they were, and the fact that one of the steel hoses is larger in diameter.

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fwiw - I did the same thing. You just have to wiggle the 5/8" hose over the larger fitting, which is a minor pain the rear, but it seems to work fine. I know that Windsor-Fox (a company that's since deceased, I think) used to recommend cutting the steel pipes short, like what jmenke described.