Need help and info to help out my autistic son with his project

Well for an autistic kid I'm proud of him he has allot lined up to drop the motor and trans in then everything came to a halt we bought these wheels and was told they will fit the found out they don't and as for the exhaust well the exhaust manifolds they told us were the only ones that would fit will cost the same as for headers they want big money for those manifolds I'm not sure now where this car is leading us I'll do anything I can for my son so he can get his car together hoping my son doesn't just give up