I'm building a '75 455 with 6X heads (stamped "4") for my '68 LeMans. I'm almost done, but I've noticed what appears to be broken sending units, one on each head close to where the "4" is stamped. I thought the temp sending unit was on the intake (?). So, does anyone have an idea? I suppose one may be oil sender (?), or should I block one or both off and move on (mild street application)?

Thanks a bunch, Double

I'm building a '75 455 with 6X heads (stamped "4") for my '68 LeMans. I'm almost done, but I've noticed what appears to be broken sending units, one on each head close to where the "4" is stamped. I thought the temp sending unit was on the intake (?). So, does anyone have an idea? I suppose one may be oil sender (?), or should I block one or both off and move on (mild street application)?

Thanks a bunch, Double

1975 Pontiac V8s DO have the coolant sending unit installed on the left (driver's side) cylinder head between cylinder #1 and #3. The right (passenger side) cylinder head is plugged in that location. 1975 Pontiac V8s locate the thermal vacuum switch on the intake manifold coolant crossover.

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I've seen a few pontiacs with a thermal vac switch in the right head . i don't remember what it ran.

Transmission-controlled spark would be a good bet, BUT, with this era automobile with all the smog stuff hung on instead of designed-in, you just never know. Put in a pipe plug from the local hardware store. My temp sender is in the cylinder head above the front (or rear, depending which side)two spark plug holes.
Hey, -4 6xs, aren't those 350 heads? Better watch yer compression for pump gas.