when i bought my 76 maverick stallion it didnt have a motor or tranie i mannaged to fit a 351 windsor and c4 transmission in it by shoe horning it in. im using stock exhaust manifolds i had to do a lil modification to them i had to shave the molding line off of the side and had to go to shorter valve covers to get my brake booster to fit its very tight but it can be done everything connected and hooked up very nice changing spark plugs takes a lil longer cause i have to remove my valve covers witch makes it alot easier to change them i had to use an exhaust manifolds from a 289 so they would fit but it works. in the jegs catalog are a pair of the same style and shape exhaust but they are performance headers a lil pricy but well worth it something you might look into i have not modified my shock towers in any way good luck with the mav.