If I milled my B18C5 Head 40 thousands and put a slimmer head gasket in would I run into clearance issues when using the Toda Spec B's?

 

I'm not sure about clearance issues, but you're likely to have issues with the timing belt tensioner not being able to pick up all the slack. Even if you only get rid of one layer of the head gasket, that'll give you a total of about .050 off the distance between the cam gears & crank. That's pushing it.

 

i recommend claying the motor whenever you question clearnence, you have to take your time and do it right otherwise you can throw your money away..

here is a good how-to that shows what i mean

http://www.c-speedracing.com/howto/claymotor/clay.html

 

what bottom end?

 

I am running with a stock B18C5 bottom end.... I was planning on using the TODA Timming belt as well, if I can get a hold of one. I heard it was more reliable under higher RPM's.