I just finished swapping out my 450hp 350cid carbed motor for a 305 HO TPI in my 85 Sport Coupe. The engine and wiring came from a 92 Z28.

It wasn't as difficult as I thought it would be. First, the engine and trans went in without a hitch. I did, however attach the wiring harness before installation. This seemed to be easier than trying to get to all the connections later.

The came the dash assembly - THE WHOLE THING. First, the easy parts. The screws that go across the top of the dash to the firewall matched up perfectly.

Now the more difficult. Since I'm not transferring the cruise control, I pushed the connector that runs across the back of the dash into the space behind the dash under the firewall. It was a little difficult because of the space, but it went.

Then, the dash itself. What a PITA. First, that brace on either side of the dash had to come out. I cut it across the top where it bends down with the stud on it. Then cut it across the lower portion just above the first set of holes. I was afraid the dash was going to be unstable, but with the steering column in place, it's as steady as a rock. When I installed the steering column I had to push the dash in to get the studs right. After you tighten it down it will stay in place.

For all that have asked in the past, YES, it can be done. For all of you that have posted how to do it, thank you. At first I doubted, but it does work. Saying "some modification is required", is an understatement. Just for info, if you replace the dash wiring, you must replace the rear light harness. At least from an 85 to a 92.

Again thanks for all the help.

 

why did you swap a 405 hp 350 out for a 305....?

 

this also goes for an 84 v8 carb dash harness to an 85 v6 fuelie chassis harness.

 

What kind of gas mileage do you think the 350 got? About 10 mpg. With gas at 3.30/gal here in TN, I just couldn't afford it.

Also, I needed an engine for my '80 Trans Am.