my 78 440-3 from a MH runs just fine in my 88 d100 even uses the d100 318 rad/shroud.

it has the #452 small "peanut" plug heads or did have. I changed them out 20,000 miles ago when I installed a set of the car #452 regular plug heads along with the whiplash 440 flat tappet cam/springs.

180* t-stat and holds around 190*- 210 in slow traffic/dog days of summer here in FL. drops right back to the 180*-190* when moving along.

I did a home pocket port clean up/guides/back cut valves/3-angle VJ on the peanut heads and have them on the shelf.

I had more trouble with it running hot before I curved the dist. with my retard timing it would heat right up. locked dist full mech advance-dialed it right in on 32* runs like a beast and fine in traffic.

my understanding the "EXTRA" water ports are around the tapered plug seat to cool it and not to be confused with the steam holes in the heads which can get blocked with incorrect gasket.

I was cautioned about porting in the chambers and pockets as it is easy to find the added water passages with a grinder in these heads. the block port that feeds around the plug seat gets blocked even though the gasket has the hole. on the standard car #452 heads this hole/port is not drilled.

this is what I concluded rebuilding my 78 440-3 from a 1-1/4 ton 10 lug chassis MH for my 88d100. and have both sets of heads on the bench picking gaskets.

machine shop said it would be fine as it is basically the same head casting.

if you go with a whiplash 440 it is as described... idles like a funny car and cuzes in daily traffic no problems runs like a beast on the street.

my speed shop said those cam specs would not work with out comp/pistons/3500 TC/gears ect. ect…

stock truck 727 turning 2.76 gears with a 29/15/15 M/T sounds like a funny car coming thru town 3rd gear idling along 25 mph choppin away.

got the 833 4 speed and 3.91sg going together next.

good luck and you will like the whiplash line of cams. works great for lopo street engines.