I have a 72 Charger #'s match, 400 2bbl. 83K.

Looking for some more oompf and to run AC on pump gas. Prob run a 323 gear for cruising.

450hp plus target.

I have the block, plenty of 440 Cranks, LY rods.

Choice:
1 set ported 906 prob 230/170 cfm
2. 516's ported that ran mid 11's prob 240/180 cfm.

Both have 214-181 valves and are fresh.

What are the piston choices, and are they usable with Iron heads. Cam should run smooth I suspect below 230@ .050.

Thanks in advance :-)

Headers or stock exhaust manifolds?

Diamond 52006 or 52007 are nice.

The 6 is for the stock 1.094 pin, the 7 is for a .990 pin if you were going to bush the rods down.

I've used the 006 for awhile.

I mean, you can always spend more and get lighter weight, coatings, custom ring packs and so on and all that stuff helps performance one way or the other. It's just a matter of how fancy you want to get.

I'd use the 516's.
Easier to get good quench, and there won't be diddly for power difference in an application like that.

450hp with ex manifolds would be a stretch though...... For either set of heads.

So my buddy has a 400 block in his 70 Challenger. It is bad news.
using 440 steel crank and 440 LY rods with new rod bolts. He also used Keith Black Hyperutectic (?) pistons at 30 over and it is zero decked. He has stock 906 heads with the 509 purple shaft hydraulic cam. (About the same duration you spec'd)
Very light weight rotating set up with the KB pistons and revs like an electric motor. smooth, fast, quiet.
Good luck with yoru build.

I'll use headers.

Do you cut the crank or line bore the block to fit the 440 journal?
I've read about it both ways.

On mine I took a 440 crank with severely damaged mains and cut it.

I've read about it both ways and it made more sense at the time to not cut the block.

"450hp with ex manifolds would be a stretch though...... For either set of heads."

Agreed, Exactly why I asked

The first 451 C.I.I built with a 400 block used a stock type forged steel 440 crank with the mains and counter weights cut down to fit in the 400 block, blue printed LY rods with the cheaper ARP bolts back in 1997 or so. The customer furnished some of the parts like the mildly ported 906 heads with 2.14 intake valves and 1.81 exhaust. I built it with a set of pump gas Ross forged pistons for CA pump swill back then, it had a Mopar M1 single plane and a BG 850 vacuum Street demon carb., it made 489 HP at 5900 RPM on a DTS engine dyno before splitting the #1 cylinder wall
I ended up having to replace the block due to massive core shift so bad that block wouldn't take a sleeve, it needed all four on the driver side
I still have that motor and I hope to try it on the local Studka engine dyno with the new block and with all the other parts and compression ratio being the same
I tried to get the customer to have that crankshaft offset ground to BB Chevy rod size and increase the stroke to 3.91 but he wasn't up for that, maybe you should consider that also The 400 and 440 motors with that stroke rock

Line-bore the block? How many shops even have the tooling for that? Really, it takes a different machine than one that is used for line honing. It also costs money.

Also, why sacrifice any of the 400 block main web strength?

I'd guess that maybe only 2% of all 451s that have been built have 2.75" mains. E-berg did it this way in Mopar Action but he's in the minority.

The first KB piston for the 451 with a RB rod had a ridiculously low weight, and also was a quench dome design for open chamber heads. IIRC the dome can be machined off. Ask the manufacturer.
451s are falling out of favor because for nearly the same money you can build a 511. The 451 is really just a 440 in a B block.

Get after it!

R.

Be very careful about your costs going this route. In the old days it was cheaper to turn down a 440 crank but I do not think that is true now unless you know someone with the right equipment.

Here in Portland OR you can't even find a shop to make a 451 these days. The shops have gotten rid of those big crank grinders since they aren't needed anymore. The smaller crank grinders that the shops have on hand can't do this type of work.

Also, the last time I quoted rebuilding a set of LY rods the cost was higher than if I just bought the 6.700 SCAT rods from Summit. ($345 for brand new rods. Most shops are going to charge more than that for new bolts and resizing) Also, the LY rods cost more to balance since they were built in the old crappy days.

Not trying to pee on your parade, just telling you that you should not assume it is cheaper to rework your old parts than to buy new parts. You can probably sell the 440 forged crank for $100 or $150 at a swap meet and put that money against a Molnar crank. Sell the LY rods for $50 a set and buy the $345 rods from Summit.

IMO, the most cost effective way to achieve the target power level is just build a 440.
Stock crank, stock rods, KB flat tops.

Super easy.

To make that power with a 3.23 gear/tight converter/AC friendly cam, the heads are going to need to be pretty decent.

I love a 451 low deck--it is overall one of the best Mopar combos ever--they rev like a chainsaw
easy to drop crank at the grinder--pick it up--small mains --Bingo!
I would NEVER spend the loot to line bore one only to wind up with thinner caps and who knows where the crank would be located then--never! Then you just chuck that crank in a lathe--get the right tooth angle and speed and make hot noodles chamfer the inner edge of the counter weights on the #2 and #4 and in less than 1 hour you have done it--no big deal--
Rod? eh..Andy is right but you can save a little with the LY's
No matter what it will be a great unit and surprise you at the results--stock
manifolds are the kiss of death and the limiting factor yet you can still build one that will haul with them just not a " magazine HP" # unit--LOL
My favorite engine I ever had on the street was a 451 low deck, SR heads, 255 @ 050 solid---That thing was just plain FUN--could turn it 7400 change gears turn it up again--the monster engines are like driving the Zamboni at the ice rink--that 451 would hook and rip!

470...............

Duane- I have 2 done 440's in stock.

But, Since this is an interesting # match 440-2 barrel 72 Charger I think the allure is with the correct block and trans. You always lead me right and I'll use the 516's.

Crabman,
I hear ya

C