Changing antifreeze 1966 427 L36

[Harry L.]

Where can I find pictures of the 2 drain plugs at the bottom of the block? And how many quarts of antifreeze does a big block take? Thanks. Dutch

[Michael G.]

Re: Changing antifreeze 1966 427 L36

Where can I find pictures of the 2 drain plugs at the bottom of the block? And how many quarts of antifreeze does a big block take? Thanks. Dutch

Drain plugs are lower part of the block, right above oil pan. Should the engine have stock exhaust manfold, drivers side drain plug will be slightly hidden by the exhaust manifold as well as difficult to get out. Capacity totally empty....radiator and block will be 5 to 6 gallons of fluid, closer to 6. A 50/50 mix is perferable.

[Harry L.]

Re: Changing antifreeze 1966 427 L36

Thanks Michael, I have read about the type of coolant that I should use, I will look for the plugs. Just hoping someone had a pic of the plug.

[Michael G.]

Re: Changing antifreeze 1966 427 L36

Thanks Michael, I have read about the type of coolant that I should use, I will look for the plugs. Just hoping someone had a pic of the plug.

Passenger side, right in front of starter. Drivers side same location, however will be masked by exhaust manifold (if stock). I used recessed allenhead plugs however yours could be hex or square headed plug. Both plugs would need pulled to empty the block.

[Harry L.]

Re: Changing antifreeze 1966 427 L36

great picture, I have seen that plug but did not know what it was for. thanks, Dutch

[Gary J.]

Re: Changing antifreeze 1966 427 L36

How would be the best way to remove. Looks like they would be a pain in the rear to remove if they have been in there all thei life. Looks like they would strip out too.

[Harry L.]

Re: Changing antifreeze 1966 427 L36

Does anyone have any experience with the removal of this allenhead plug? Dutch

[Michael G.]

Re: Changing antifreeze 1966 427 L36

Does anyone have any experience with the removal of this allenhead plug? Dutch

Don't be bashful Harry. No need to collect up opinions here........grab yourself the correct wrench and get busy.

[Harry L.]

Re: Changing antifreeze 1966 427 L36

Thanks for the incentive

[Harry L.]

Re: Changing antifreeze 1966 427 L36

The passenger side has the allenhead plug in the middle and a 4 sided plug at the far end. The drivers side has 3 allenhead plugs with a 6 sided plug in the middle above the allenhead plug. Is this norm?[ATTACH=CONFIG]47458[/ATTACH][ATTACH=CONFIG]47459[/ATTACH][ATTACH=CONFIG]47457[/ATTACH]

[Gary J.]

Re: Changing antifreeze 1966 427 L36

Harry, any luck in getting the plugs out?

[John H.]

Re: Changing antifreeze 1966 427 L36

The passenger side has the allenhead plug in the middle and a 4 sided plug at the far end. The drivers side has 3 allenhead plugs with a 6 sided plug in the middle above the allenhead plug. Is this norm?[ATTACH=CONFIG]47458[/ATTACH][ATTACH=CONFIG]47459[/ATTACH][ATTACH=CONFIG]47457[/ATTACH]

Harry -

The square-head plug directly below the fuel pump doesn't get touched - that's where you remove/install the fuel pump pushrod on a big-block. The two you want for draining the coolant are one on each side, just above the pan rail.

[Harry L.]

Re: Changing antifreeze 1966 427 L36

I am still researching this event and waiting for my waterpump from Bill. John, on the left side of my block there are 3 allenheaded plugs, 1 on either end of the block and 1 in the middle, right below a 6 headed bolt as in the 3rd pic. Is that the drain bolt or do I use the allenhead plugs to drain? On the right side I only have the allenhead plug. thanks Dutch

[Stephen L.]

Re: Changing antifreeze 1966 427 L36

Here is a photo of a 67 427 coolant drain plug location. Both sides are in a similar location. Steve.

[Richard M.]

Re: Changing antifreeze 1966 427 L36

Harry, the small allen head plugs on the drivers side of the L36 are oil galley plugs, the larger hex head plugs one on each side go into the water jackets.