Header installs on early econolines

I'm looking for information regarding issues (if any) with installing headers on v-motor swaps.
Any help would be appreciated, Thanks

I used 89-ish Mustang headers on mine with an 89 5.0L HO. They wouldn't clear the floor, so I cut out sections, then cut out more to increase air flow.

I've heard that some year of Mustang headers fit without need to to cut the floor, but I don't know what year. Sean O'Dell at Blue Oval Engineering sold them, or modified them.

Also, 351s are wider than the the 289/302 and you will have to cut the floor no matter what.

Sean Odells (Blue Oval's)headers arent modified Mustang ones. They are custom made long tube headers that fit in the stock doghouse. These were originally designed by the late great Eugene Phillips.

Used shorty's on mine..you should not really have a problem, floor wise, as you more then likely will have to cut the floor anyway.

I could have sworn Sean told me he used Mustang headers, but I must have misunderstood.

Anyway, here's my '65 and how much I had to cut to clear the 80s Mustang shorty headers.

I called Sean to verify and they are as I said, custom made, nothing Mustang about them. He is currently going thru a financial crisis and doesn't have the cash to put out to make any at this time. He hopes to make more once he gets thru his current situation. I have 2 sets myself made by Eugene and Sean says what he sells now is off the same jigs and identical to what Eugene sold.

alright attempt number 3 is the charm
Thanks guys i appreciate the feed back.
I'm glad i signed up for this forum.

My floor was cut by the previous owner to fit the stock 4.3 motor. I pulled it and rebuilt it to be different from the v8's. I'm gonna attach a picture of my clearance.
Can you give me a measurement from the head to the floor opening on yours?

Thanks Again Puzzled

Just ordered a set of long tube Hedman's 69400's.
I will have them modified if need be.

My long tube cliffords hit my motor mount on my 240 cheaper to have them modified or buy shorties?