Stock 440 Block Horsepower Limit

[Schober Motorsports]

Hey guys, curious to see what everyone has seen out there about what these 40+ year old blocks can handle for horsepower. Purely assuming that the bottom end is forged aftermarket stuff and that everything else in the motor is up to snuff... What can a 440 handle hp range in ya'lls opinion? What have you guys done/seen? Thanks!

 

[dvw]

I've done 700 and it lived. I've done 700 and its broke. No detonation is a big help. The one we broke the crank in half at the #3 main as well. It also had aluminum caps.
Doug

 

[lewtot184]

i'm not as generous as dvw, but horsepower numbers seem to be very subjective. for me, anything approaching 550 real horsepower would at least get better main caps. reducing piston and rod weight as much as possible helps the bottom live longer. I gringe at steel rods and high horsepower engines. I think a better block is worth the money for big horsepower.

 

[bobtile]

Ill be pushing the envelope witb the engine that will be on the dyno shortly.
Im hoping for about 725ish.
Block filled and aluminum caps.
We'll see what happens.
What is your definition of "handle"?
I think a good block will support the 700 range, but the question is how long.

 

[bobtile]

Are you running a girdle?
I didn't put one on because I wasn't sold either way on them.

 

[not so famous bob]

Are you running a girdle?
I didn't put one on because I wasn't sold either way on them.

Hughs engines claim they ran one on the dyno at a little over 900 h.p., w/ no problems. They had a girdle on it, and of course it was forged everything. I know a guy that had a low 9 sec. duster/ a 496 in it , he had to back the carb. down to 9.60`s to keep from cracking the block between the cam and main bearings, BUT, he didn`t have a girdle. If u think girdles aren`t worth doin, on a big block mopar, u better brush up on the facts. There probably isn't an engine out there that it will "help" more. I even had my block and mains cryo`d .

 

[bobtile]

Hughs engines claim they ran one on the dyno at a little over 900 h.p., w/ no problems. They had a girdle on it, and of course it was forged everything. I know a guy that had a low 9 sec. duster/ a 496 in it , he had to back the carb. down to 9.60`s to keep from cracking the block between the cam and main bearings, BUT, he didn`t have a girdle. If u think girdles aren`t worth doin, on a big block mopar, u better brush up on the facts. There probably isn't an engine out there that it will "help" more. I even had my block and mains cryo`d .

The word "claim" certainly doesn't sell me.
Running on a dyno a bit doesnt sell me unless it was run without a girdle as well.
How do you know that the guy you know has a motor that was going to break if he didn't back it down.
Your still not selling me on a girdle.

 

[BeepBeepRR]

My neighbor just had a 400 stroker built. I don't know all the specs but it dyno'ed at peak HP 723 hp 678 torque. I think he said it was running chevy 454 rods.. I have the dyno sheet here with me. I guess its legit. This is the same guy who grenaded the last engine he had built. forgot to add that it has a displacement of 425 cubes.. The thing is sitting in my garage now waiting to be put back in his 69 barracuda. Yep thats ford blue. It matches his tube chassis.

 

[lewtot184]

i'm not a girdle fan on a Y block. cross bolt mains and light components are my preference. I don't understand wanting to build big horsepower for an engine that was designed in the '50's and never up graded for strength. when the hemi's came out they had about 100hp more than the wedges, and they weren't 700hp, and the factory had to cross bolt the blocks to keep them together. I also think people put to much faith in fastener strength. fasteners are supposed to create friction between the mating surfaces to hold things together. when there isn't much mating surface, and a low strength cap, what good does a 200,000psi stud do? blow the caps out and destroy the engine but the studs survive? I seen a 440 explode at power levels well below 700hp and this was with light components; very ugly and thankful the driver/car didn't crash. i'm paranoid of big power and stock mopar blocks; they're far weaker than the magazines/internet or motor messiahs say they are.

 

[1967coronet440]

You’ll get a lot of different opinions and answers on this question.

 

[Schober Motorsports]

You’ll get a lot of different opinions and answers on this question.

No doubt about it. Just would like to hear some experiences or advice that you guys have out there. Been doing research on those trick flow heads for my bracket car and will be in the 700 hp range and I want a reliable motor that will last!

I run a girdle on my 440 w/ main and head studs. Also have the smallest piston I could get with the combo. Right at .000 deck and will be about 13-1 cr with the trick flows.

 

[1967coronet440]

No doubt about it. Just would like to hear some experiences or advice that you guys have out there. Been doing research on those trick flow heads for my bracket car and will be in the 700 hp range and I want a reliable motor that will last!

I run a girdle on my 440 w/ main and head studs. Also have the smallest piston I could get with the combo. Right at .000 deck and will be about 13-1 cr with the trick flows.

View attachment 538640
View attachment 538641

Mines a 12:1 victor head around 700-750 range. Girdle, eagle crank and rods, mahle pistons, girdle. I’d say go for it, should be fine if it’s assemble correctly! Hope to see you guys out at 41 next year!

 

[451Mopar]

I don't have a good answer. There are various way to make the power, and different applications. I is likely a 800 hp NA engine in a light drag car would last, where a 800 HP nitrous engine in a pull truck would not. I think the question is more related to how much do you spend to upgrade a stock block vs the cost of an aftermarket block. But now another issue is being able to get aftermarket blocks? If this was another brand other than Mopar, it would be an easy choice as there are plenty of affordable aftermarket blocks for GM and Ford.

 

[451Mopar]

FWIW, the Charger engine is a 400 "230" block, BCR aluminum main caps and 1/2" girdle, 440 source 4.15 stroker kit with the short/light pistons. The heads are Hughes CNC Max wedge Victors, and a mid sized 272/278 @ 0.050", 0.726" lift. I have not dynoed the engine, but I think the 1,000 cfm 4150 carb may be limiting the power to around 700?

 

[moparcrazy]

Hey guys, curious to see what everyone has seen out there about what these 40+ year old blocks can handle for horsepower. Purely assuming that the bottom end is forged aftermarket stuff and that everything else in the motor is up to snuff... What can a 440 handle hp range in ya'lls opinion? What have you guys done/seen? Thanks!

View attachment 538448

I'm running a stock Bottom End, F'N CAST CRANK !!!! LY RODS, KEITH BLACK HYPEREUTECTIC PISTONS,
TRANSBRAKE!!!!!, LEAVING @ 3000RPM SHIFTING @5000RPM 10.36ET @129MPH PUSHING A ALL STEEL 65 PLYMOUTH WEIGH'S 3530LBS 700HP ALL DAY LONG, 3 YEARS NOW????? FORGOT TO ADD 250 SHOT

OF NITROUS,​

 

[biomedtechguy]

Your still not selling me on a girdle.

BCR aluminum main caps and 1/2" girdle

IF I (or Jim LaRoy) use a stock block (not likely) I would definitely use this particular cap and girdle set: http://www.bcrproducts.com/caps_and_girdle_system.html
However...
My goal using the Holley 6bbl (a MUST for my 70 V-Code Roadrunner) is 6XX HP and 6XX Torque. If I left it at that, I may say a stock block with BCR girdle and caps would be ok, BUT I am thinking about a nitrous power adder setup and I would like to build this stroker ONCE and be done. I defer to Jim's expertise when the day comes, but I am likely to use some kind of aftermarket block. If I add nitrous, it will handle it, if I don't, it's worth the peace of mind to have an overbuilt motor IMO.

 

[IQ52]

Everything you build is a gamble. Build it as tough as you can afford. But, these two have yet to fail...............

My 500"/440 using 440 Source crank and rods, Ross pistons and a Pro-Gram 4-bolt main conversion has progressively gone 750, 850 & 928 horsepower.

The 451 stroker with a factory 440 forged crank, Scat H-beam rods, Ross pistons, stock main caps and ARP main studs has hundreds of pulls from 621-787 horsepower. It is now at 580 HP and running in the shop truck.

 

[Challenger340]

I don't think there is an exact "number" anyone can definitively say X for example, above or below which a Block will break, vrs be fine ?
IMO, just far too many factors to longevity at any power level ?
* Bobweight of the rotating assembly itself
* Balancing factor for the rpm, 50% or slight overbalance
* The rpm itself
* How it's firing, ie: detonation, which even though nobody's hearing it with Dome Pistons and Heads that Flow off the backside of the cylinder(remix), it can still be there, and remember here... a "little bit" of detonation makes the best power, so in my experience best to back down slightly from that highest Track mph.
and of course,
* the differences in the Blocks themselves, thickness of the detroit wonder metal in places
on and on
We've seen them live just fine at 700+ with just Main Studs... on stock caps !
and then again,
we've seen them presenting during refreshening after a mere 100-200 runs at 750, with main webs cracks, #4 registers developing mountain ranges, pretty much getting ready to calve, and with Aluminuim Caps/Girdle/partial fills in place ?

I DUNNO !

 

[451Mopar]

Part of the stock block issue is core shift and cylinder wall thickness. My 500 also has a sleeve in the #7 bore. Really, at the time (when the aftermarket blocks were a bit less expensive), I could have gone to aftermarket block for about $1,000 more than I put into upgrading the stock block. The BCR mains/Girdle are nice and for the $800 you get good ARP studs and such, but you have to add the cost of machining it so it all works together. Depending on the machine shop, the machining could cost almost as much as the mains/girdle? So you can have an easy $1,300 to $1,500+ into doing main caps/girdle.
If the block needs a cylinder sleeved, add even more $$$.

 

[dvw]

Part of the stock block issue is core shift and cylinder wall thickness. My 500 also has a sleeve in the #7 bore. Really, at the time (when the aftermarket blocks were a bit less expensive), I could have gone to aftermarket block for about $1,000 more than I put into upgrading the stock block. The BCR mains/Girdle are nice and for the $800 you get good ARP studs and such, but you have to add the cost of machining it so it all works together. Depending on the machine shop, the machining could cost almost as much as the mains/girdle? So you can have an easy $1,300 to $1,500+ into doing main caps/girdle.
If the block needs a cylinder sleeved, add even more $$$.

It's not so much core shift and wall thickness. You can test for that. What you can't test is main web integrity. Granted the 400 blocks are some what thicker in this area. There are plenty runing around that have't broke. I agree light parts and NO detonation will go a long way towards longer use. The one I broke had BME rods and fairly light Venolia pistons. Never saw over 6800 rpm.
Doug