This is the info on my 408 build.
400 block and crank
Stock rods offset bushed to accept cleveland piston& pin
all balanced
Keith black kb177 pistons
Mpg windage tray
5/16 chrome moly pushrods
clevite 77 bearings
melling high volume pummp
Chi 4v heads cnc ported
1.70 crane gold rockers
Cam research solid cam .620 lift 255-266@.050 108 lobe sep.
Chi 400 3v intake no porting 1050 dominator
8 quart oil pan
mezeir water pump
msd 6al and distributor
This combo made 551.9 hp at 6300 and 519.8 tq. at 5000 with 2" by 32by 3.5 headers and 538hp at6600 and 519.8 tq at 5000 with 1 7/8 by 31 by 3 inch headers.

on edit, title change -blizz

Is this a predominantly street engine? How are its manners? What type of vehicle did it go in? Any more you can share?

Thanks in advance.

This engine will have limited street use as I did cement the block and the oil temps do come up as seen on the dyno.I could have run coolers to keep it cool but it is going to be a 1/4 miler.The engine does have easy manners and will idle at 900 rpm all day, I think anyone looking to run this combo on the street should stay away from cementing as it probably not needed until a higher hp is reached.The engine is going into a 73 cougarxr7 that I've owned since 81.The car is being painted as we speak and putting in roll bar and sub-frame connectors.I'll run 4.56 gears 4500 convertor and rollerized c6 with trans brake,the slicks are m/t 29.5 by 9 by 15 with caltracs and the car weighs about 3600 withme in it.Any estimates on et would be welcome. Thanks Steve

What is the max amount you can fill the block, and still run on the street? My 400 will be a street terror and never on any big trips.

That is some serious power.
It may seem odd but given the way those new heads flow, as I compute it you might have another 30hp or so waiting with some more tuning, unless that dyno had mufflers on the end of it.

If the 3600 lb w/driver is right for that big Cougar, here is my prediction, open headers and underhood air intake:
1.59
7.22 at 94.6
11.37 at 117.9
Go hammer on it and post back, the 1.59 assumes the car hooks, that is the hard part at least for me.

Thanks WerbyFord we're just getting it into the car now,sorting out a few changes i've made took longer than expected.I couldn't get the 2" headers to fit so Im going to run the small ones for now and get a set of step headers made over winter.Also the painting and roll bar took longer than expected.I also bought a set of crane gold 1.73 that i'll put in over winter so I put up any times iget if winter doesn't hit first.
Steve

Where do you guys get your big tube headers at? I'm looking for two inch or bigger ( heavy nitrous use ) and last night at work I couldn't find any for under 5-6 hundred dollars. My 400 I'm building will be going into a 86 Mustang with front motor plates. I'm hoping using the 351C headers will work, seeing how the 400 is an inch taller.

I filled to the bottom of water pump holes,but I don'tthink you need to fill this block until about 600hp,thats just my opinion though also I used 351c headers and cut them to fit,but this winter going to have a custom set built to fit as I think there is some power to be had there.
Steve

The unsupported length of the bore in the 400 block makes block filling important, I reccomend filling at least the bottom 1.5-2" of the block for any 500+hp 351M/400C blocked engine.
Cheers.

The 400 has long liners but it also has a long rod that takes the strain off the side wall . I have run the 400 in pickups with 550 hp with out any problems . i run a built 400 with a 250 shot and never had wall problems but you do need to use a truck block the early car blocks are bad news . I split right between the lifter bores . I am running a engine about the same as you but my block is bored .060 and the crank is off set ground .030,this gets the piston to the top of the bore . I am running this in a 3200 pound with driver 1986 mustang with headman 1.7/8 x 3 headers,Ported 4v Cleveland heads and a Holley strip dominate and 850 .

Millar what kind of power are you making?Iwould be interested to hear your times.I ran mine in the fall and it ran 11.88 @ 114 the car weighs about 3400 without me,I thought the power was down abit but I did have a highspeed miss that was caused from to low of voltage to the MSD.Im hoping to get around 117mph if possible.