I have a 36 dodge with a healthy 440 I used the stock upper and lower tanks and had it recored locally.That being said you still can't run a high pressure cap,I think a 7lb cap max.I have a mechanical fan with a pusher in front.It cools ok on the freeway but in traffic it will boil over,so I have the pusher to overcome that and has not overheated yet.I've had in nonstop bumper to bumper in temps in the 90s with no issue.If I was to do it again I would bite the bullet and buy a walker.
Joe