I did a engine swap on my 76 chevy truck and now the truck is having a problem. It has a chevy 350 I think that it has a cam but I'm sure it is mild.. at Idle it is around 1200 and when I drop it into gear is is around 300 to 400 by sound no tach. I put a vacum canister on but no change.. It has a turbo 350 I used the old torqe converter and it had a 350 in before. it is a full time 4x4 too. any help would be great.. Primo