hi,just picked up a late 60's bird wren, what would be the correct engine? it currently has an older 2 1/2 briggs. also has plate between forks.what decal would belong on this? chain guard? I think its a penneys foremost ,I have a runabout & it doesn't have the plate. I'm thinkin its a penneys brand, no tatags,non original yellow color........any thoughts on this are appreciated......thanks Mick