expansion tank-427/425?

[Michael F.]

Does the 66 427/425 have an expansion tank? Also is the themostat housing alum or iron and what is the number on it? Thanks.

[Peter M.]

Re: expansion tank-427/425?

No expansion tank. Therm housing is GM#3877660

[Michael F.]

Re: expansion tank-427/425?

Thanks Peter, you confirmed what I suspected.

[Craig S.]

Re: expansion tank-427/425?

Michael - also, your radiator should be copper/brass with integral cap, the expansion tanks were only used with the aluminum radiators...Craig

[William V.]

Re: expansion tank-427/425?

The 65 396 & the 67-L88 were the only c2 big blocks with aluminum rad & expansion tank

[Joe L.]

Re: expansion tank-427/425?

Craig------

Not quite. All 1969-72 big blocks with copper-brass and aluminum radiators used an external supply tank. For all without A/C, the supply tank was the same one used for small blocks with aluminum raidators. For big blocks with A/C, a cylindrical brass tank was used.

[Craig S.]

Re: expansion tank-427/425?

Joe - thanks for the clarification, my mind is usually in the midyears...didn't mean to misconvey information and I learned more!...Craig