I am putting a SBC with a 700r4 tranny into a 49 GMC pick up. I need to cut the firewall/floor a bit in the center to clear the tranny. Does anyone know if there is an aftermarket cover plate that replaces the original flat plate that will allow for a transmission hump to clear the top of the unit. I'm finding a number of stock plates but I thought that as the mod I am making is a fairly common one perhaps there is a premade plate that I can buy.
Use a small steel wheelbarrow tub and trim it to whatever size you need. They're cheap and properly shaped. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
I put a 350/TH400 in a '49 3100 and had to make 3 cuts in the toeboard, then peel the sheet metal upwards to clear the transmission. This created pie-shaped gaps, so I cut some pie-shaped patches and welded them in the gaps. I then beat on the transmission cover until it conformed to the new shape of the hole it is supposed to cover. It went a lot easier than I expected, and once the floor mat is in place, you cannot tell that anything was altered.
1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission
Similar to Carl, I cut a SMALL arch out of the toeboard and a small arch out of the cover. Fit so close and smooth all I had to do was put the screws back in it........I'm running small block and 700R4 in my 52 panel. Maybe GMC is a little different???
1950 3100 with TH350. Fit the cover plate. Mounted a lokar cable shifter to cover. Now need to fasten cover to floor. Holes in floor were welded shut when floor replaced. I need to drill new holes and contemplating:
1. Thru holes with bolts on backside. This would be tough because of the large flange on backside and potentially nuts not fitting. Plus the hassle of having to put nuts on backside from under.
2. Tapped holes? What size? I’m thinking 1/4—20
3. Sheet metal screws. May not be rigid / strong enough for shifter?
My 49 GMC was already butchered up to accept a 250 and TH350. The builder cut way too much. I found this Custom cover plate on line and used it as a guide to fab up one similar. Unlike Carl's good idea I had alot of hole to cover. My cover.
1950 3100 with TH350. Fit the cover plate. Mounted a lokar cable shifter to cover. Now need to fasten cover to floor. Holes in floor were welded shut when floor replaced. I need to drill new holes and contemplating: 1. Thru holes with bolts on backside. This would be tough because of the large flange on backside and potentially nuts not fitting. Plus the hassle of having to put nuts on backside from under. 2. Tapped holes? What size? I’m thinking 1/4—20 3. Sheet metal screws. May not be rigid / strong enough for shifter? Other ideas or feedback?
I faced the same dilemma as you. I believe the original was held on with sheet metal screws, so that's what I used. Because there's so many of them it's plenty stout enough to withstand a shifter.
