coolant over flow tank - 68 BB

[Dale P.]

what is the correct over flow and cap for a 68 BB corvette?

[Grant W.]

Re: coolant over flow tank - 68 BB

Hi Dale
If you have a copper rad or brass expansion tank. The cap is RC 15. If you have an aluminum expansion tank an RC 26 is used. The RC 26 cap do not have the circle around the 15# and RC 26

RC 26 cap has an alum center rivet and the RC 15 has a brass center rivet.The rivet has either a flat depression on the indented, V shaped, Depression. A round head rivet is not original.
Hope this helps.
Grant

[Mark J.]

Re: coolant over flow tank - 68 BB

what is the correct over flow and cap for a 68 BB corvette?

My understanding (from a possibly outdated Tech Info Manual and JG) is that in 1968 the bigblocks (except for the L-88) did not use an expansion tank. The radiator overflow hose dumps to the street.

[John H.]

Re: coolant over flow tank - 68 BB

the RC 15 has a brass center rivet.The rivet has either a flat depression on the indented, V shaped, Depression. A round head rivet is not original.
Hope this helps.
Grant

Grant -

Photo below is the original RC-15 on my '69 Camaro.

[Rich G.]

Re: coolant over flow tank - 68 BB

Mark

I thought that too. It is certainly true for the L71. Maybe not for the lower HP engines?

Rich

[Grant W.]

Re: coolant over flow tank - 68 BB

Grant -

Photo below is the original RC-15 on my '69 Camaro.

HI John
You know its a funny feeling someone was going to say a round head rivet maybe correct. I have seen these round rivet caps. I had a bunch of them a few years ago. I only have the RC 26lb ones. The cap you pictured from your camaro is like the ones I've had in the past or maybe mine stashed away somewhere where I can't find them. Although it came off your camaro I don't see why not it doesn't apply to a corvette too. But I'm just going by the 68 69 Judging guide. There have been discussions about the flat head rivet. I guess we need to find someone with a 68 or 69 that had the round flat rivet head that is on their original car.
I wonder if Joe has the flat rivet on his 69???
Thanks, Grant

[Jack C.]

Re: coolant over flow tank - 68 BB

No overflow tank on my L68 BB 400 hsp.

[Michael W.]

Re: coolant over flow tank - 68 BB

'Overflow' tanks didn't start till '73, proper name is coolant recovery tanks. There's one exception which is in '62 IIRC.

Expansion or 'surge' tanks existed on Corvettes prior to '73 and as stated above the only '68 BB that got one was the L88.