Im in the process of installing a 440 & 727 in my 66 Coronet 500 where a 318 Poly & 727 once resided.
I have a new reproduction dipstick and tube, I think it would be fine with exhaust manifolds but the #6 header tube is in the way (Hooker Comps.)
Would another body style dipstick be more vertical? or are those aftermarket flex ones the way to go?
Dave

You can get a flex tube that fastens to your firewall. IMO that would be the way to go for ease of installation and use. I have the flex on my 408/727 (bolts to the bellhousing) in the Dakota and it is a pain because of the short length.

if you are looking for function vs stock
I used a VAN tube.
was 518/small block
easy to reach now
nowhere near the headers
cut off the mounting tab-
relocate to the cylinder head
(rear/bolt hole near intake)
weld tab back on.

I found this locking one at Summit
http://www.summitracing.com/parts/HUP-HP1235A/Application/?prefilter=1

Anybody ever use one?

Just bend the tube to where you need it to go.

I just did the same thing, big block swap with hooker comps. I just put the dipstick in, put a bolt just a few threads in to keep the mounting tabs hole lined up with where it was going to be bolted down, and bent it away from the number 8 primary. I bent the mounting tab so that the dipstick spun counterclockwise away from the primary, if that makes sense.

put super comps in my truck last spring; (318/727) had to bend my trans dipstick tube on that one too; never had to with the old "alum a coats" we put in my brother's Ramcharger though.
I liked those headers they held up quite well; but I like the price I got this set of Hooker ones too. Considering that I "made do" and yes they ARE made for the truck chassis; not some others that were "modified" to fit. Evan came with the lil "instruction sheet" that said that bending of the dipstick tube may be necessary.