How mean is your SBC build going to get? If you already have the 200, I'd use it. If you blow it up, you can always get a 700R4 later. http://www.700r4transmissionhq.com/gm-automatic-transmissions/ https://www.jalopyjournal.com/forum/threads/700-r4-vs-2004r.771724/ http://www.hotrod.com/articles/ccrp-0903-th-200-4r-transmission-build/
Might be a good idea to crawl under there and get some measurements. IIRC the 700 is a bit bigger than a 200 or TH350. I know there is a heavy crossmember there somewhere but I forget where it is.
Plenty of room for 700r4. Went to Pamona lots of insperation. I sure hope stock front axle and frame work well with the one ton wheels and 70 mph.
I believe "Widow Makers" were earlier and the Firestone "RH-5°" two piece design. Outer rim where the side ring and rim connect along the center line of the assembly. Not to be confused with the 5° three piece design. I'm not an expert but some good info here: http://forums.aths.org/PrintTopic172090.aspx and here: http://www.fatfenderedtrucks.com/widowmaker.html
Thanks for that info. Makes me want to find out if anyone makes a modern wheel i could add stock centers to?
Hey neighbor, I had these guys swap my split rim centers into new tubeless hoops many years ago. It was pricey but the project warranted the cost. I hear they are contracted to Les Schwab now so you might be able get the local store to handle all the logistics, for a fee. They are over in Pasco. http://www.amwheelspecialist.com/what-we-do/