70 C10 SWB Makeover

[lilred2]

I am definitely one that hates the optispark. I have been through 4 of them in 20,000 miles and you have to take the water pump off to replace them.

I don't think it is common i have never seen another one. The tach works I tried it on a BBC because I thought it was bad. It's cool because it goes to 7 or 8,000 rpm. I bought it from Manes truck parts in Kansas City back when he was selling parts out of his garage.

[AnotherWs6]

And the tach is reasonably easy to hook up? Do you need a new printed circuit etc, or can you just mount and wire it on its own without messing anything up?

[lilred2]

Not sure it's been too long since I have looked at it and I bought it from Manes all done. It fits perfectly in the factory tach location though. I need to fix the temp gauge here soon so if I have to take it out I will get a picture of it.

[lilred2]

Here are some instructions I found for installing a second gen tach.

The following instructions are from (user) Original69. from the 67-72 board.

Z28 Tach in a 67-72 truck.

Parts needed are the tach, at least 8ft wire. Crimp on ends, 6 nuts same size as the z28
guage studs, grommet, plastic cleaner, drill bit etc. I’m sure I missed something..


Here is an overveiw of the tach install. I used a tach from a 79 Z28 cluster.

1-Dissasemble the rear cover by removing the screws on the edge. I think there are 8 of them . Set it aside.
2-Take out the black metal plate and set it aside.
3-Take the plastic plate out and you will need to remove the lines in white that are there. I used a Meguires plastic cleaner and a whole lot of rubbing. Be careful not to remove any of the other white lines, only the ones where the tach is going.
4-Get the metal plate, the one with the black side and you will need to remove the area where the tach will be. I removed just the circle area to the edge. The tach circumference should be about ½' larger than the circle you are cutting out. Go slow here and do a good job.
5-You will have to trim off the small tab on the tach where it sticks out. Don’t worry about the small notch that’s there, you won’t see it when it’s done. I did cut two small pieces off of the edge for the dash lites to show thru at night. About ¼'
6-Put the tach where it goes. I had the bend the bottom and top edges with small pliers before it would fit.
7-Take the tach back out and you will have to do some work to it now.
8-The tach has 3 studs coming thru an insulator plate. This will have to be removed. I took the 3 nuts and insulator off marking on paper where wires went. (grnd, pos, tach). You will have to screw the 2 small nuts on the studs one at a time to DOUBLE NUT them before you cut them. I used a cutoff wheel and cut close to the top nut. Then back one nut off and when you do all three hook the three new wires onto the shortened studs.
9-Put the tach back into the cluster and turn it around finding the best fit in the front. I used sheet metal screws to hold it in. You can drill a small hole then screw the sheet metal screws in close along side the tach. This will not show in the front and is good enough to hold the tach from moving.
10-Now take the rear metal piece and figure out where the tach screws could possibly hit. It is very close here. If you need room take the plastic circuit piece off, then use a small ball peen hammer and hit it a few times to bulge it out some. Be careful you don’t hit it out too far as the circuit plastic might not want to go back on. Mine is very tight but I needed the clearance inside.
11-Drill a small hole big enough for the 3 wires and a rubber grommet to pass thru the rear plate.
12-Check everything before you screw it all back together to make sure. I also put a few pieces of electrical tape where the studs might hit the inside of the rear plate.

[AnotherWs6]

Not sure I'm following 100%...... Is there a plate behind the instrument panel that gets cut or is he talking about cutting the whole panel itself? Another way to word it - does the tach fit in the same, existing hole where the factory tach would go?

[lilred2]

He must be talking about the plate behind the cluster panel because mine fits in the factory Bezel.

[AnotherWs6]

OK - gadam they are expensive!!!! Just went on ebay wow!

[lilred2]

Haha! I looked and said the same thing. They aren't as cheap as they used to be.

[AnotherWs6]

Now I'm thinking about and vintage looking aftermarket one to do the same thing with. Hmmmm..... Ideas, Ideas. Sorry for the highjack.

[lilred2]

That would be cool. Don't worry about it I enjoy talking about these trucks.

[lilred2]

Going to start working on this again soon. I just bought some original front fenders for it because the ones on it are after market and fit poorly. One of the originals is very nice and rust free and the other will need some work. I will hopefully start getting it straightened up in a couple weeks.

[lilred2]

Been a while but I did an ls swap on it so I will update pictures for that. This one is removing the LT1.

[lilred2]

LS going in

[lilred2]

I made a short video of the truck. It’s been a while and it drives me crazy that it has been sitting torn apart so long but I am going to start on it again and hopefully make some more videos about it.
https://m.youtube.com/watch?v=FW0P09qMHhw