1976 28ft silverton engs were replaced with gm 5,7 long blocks edelbrock intake Osco risers and mans. and a half cooling system from eco cool .I m changing the ans and risers and ant to make a full system I have the thermostat housings. I have a heat exchanger from crusaider witch I can make work.it is said to have come from a 5.7 full system? the tank has 4 inch end caps.does this sound like it will work for a full system? the boats all near me are 454s does 4 inch sound right to you guys? thanks