6-speed Trans Modification

Q: 6-speed Trans Modification

I want to install a 6-speed transmission in my Firebird since here in the Netherlands, gas prices are expensive. Is this possible?

A: if you want to install a 5 or 6- speed transmission, go ahead. I’ve installed a 700r-4 in a 1968 Camaro convertible and I love it. When my Firebird convertible goes back together it will most likely have a 2004-r or 700r-4 in it as well.

The benefit to an overdrive is highway mileage. If you spend a good deal of your time in the car at highway speeds, an overdrive will DEFINITELY improve your milage per gallon. With a 310 hp 350 CID and the 700r-4 in the 1968 Camaro it gets 24 MPG on the highway.

I’m sure American cars of the vintage we have are hard to come by where your from so I dought adding a 5 or 6-speed transmission would hurt it’s value. And, you could always keep the 4-speed and sell it with the car if you do sell it to a purest. I was at an auction last year and watched a 1969 Camaro convertibe that was factory stock looking on the outside and the interior but had an LT1 and 6-speed transmission sell for $26,000. It was a nice job.

As far as which transmission, look for on with the universal B-O-P bolt pattern. If you cannot locate one, you can use an adaptor plate to bolt a Chevy bellhousing to the Pontiac motor. I’ve never switched standard transmissions but I’ve seen a 1969 Camaro with a 5-speed with a stock console and would not have known it until the owner told me.

My advice is take carefull measurements. If you have to cut you tunnel, cut the area out without bending it using a thin bladed saw. Fabricate a patch out of other metal and save the piece you cut. If you want to go back to original the piece can be easily welded back into place.

Wish I had more technical advice but I hope this helped.

Any proposed updates, changes, pictures, and/or corrections, please use our comment section below (may need to click on permalink to access comments feature). Information is subject to change and offered as is without any warranties or guarantees. Please review our Term's Of Use for more information.