I have a g30 1979 class c motorhome that i have pulled the original 400 sbc from. I have a 454 bbc i would like to drop in. Unfortunatly, looking at the motors side by side and the very litte space i have to work under the hood, I do not think it will fit. As far as bolting up to the transmission and motor mounts, were all good there. Seems to me like the manifold will touch the frame and there will need to be definate cutting/grinding under the doghouse. Is the a smaller manifold/header that will clear the frame? I forgot how big this engine really is. Once I make some lifting mounts, I will have a better idea but ive measured many times and I dont think it will fit. I may be wrong but I do think the 454 was not an option this early in the application I have. I think somewhere around 83 maybe they became an option. Makes me wonder if they opened it up a bit. Has anyone had any experience with this swap? I need to make this thing fit. And will i need a bigger rad if I can make it fit? thanks. Any feedback at all is greatly appreciated.