I have a 1973 440/727 combination (213 heads, OEM MH exhaust manifolds, 4bbl TQ carb) out of a motorhome, along with a set of 452 heads and auto exhaust manifolds. It's hard to find information on MH 440's, but the net hp/tq is supposedly somewhere around 220/320. The engine and transmission have 58K miles on them and were reportedly great runners when taken out. I want to get the performance of the engine (8.2 compression) up nearer to 1970 non-Magnum specs, which are listed by one source as 350 hp and 480 ft/lbs torque. If the bottom end checks out OK I'd like to keep it as is and gain the desired performance level by milling the heads (213 or 452's? .050-.060"?) and using appropriately thin, (possibly MP .020" steel shim) head gaskets. Assuming the OEM cam is designed for low-end, I'd even like to keep it as well. Is this realistic, has anyone done it, or does anyone have suggestions based on actual experience? Thanks for any comments!
Budget 440
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Rob C
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YEa, it is doable.
Use the performance cam that came with those engines, MAgun, 6pac cam, all the same with different names.
060 off the head is about right. Do not get to caught up in getting the exact ratio. For thatTQ, you'll need to find out the rod size and use AFB/AVS rods bent 3/4 inch shorter or find TQ rods. (LOL on the TQ rods, though it is possible, it could be expensive)
Use the performance cam that came with those engines, MAgun, 6pac cam, all the same with different names.
060 off the head is about right. Do not get to caught up in getting the exact ratio. For thatTQ, you'll need to find out the rod size and use AFB/AVS rods bent 3/4 inch shorter or find TQ rods. (LOL on the TQ rods, though it is possible, it could be expensive)
Chryco Psycho
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how far down the hole is the piston @ TDC ?
You would be better off swapping a set of the 516 or 915 closed chamber heads onto the engine , to get quench you need to get the dead part of the chamber within .060 of the head. Good cam choice will help build compression also .
If you decide to mill the heads try to eliminate the part of the chamber away from the valves but I am not sure you can mill the head that far this may leave the deck surface to thin , you will also need to mill the intake or the intake side of the heads so the intake will bolt on . You could also mill down the closed chamber heads .
You would be better off swapping a set of the 516 or 915 closed chamber heads onto the engine , to get quench you need to get the dead part of the chamber within .060 of the head. Good cam choice will help build compression also .
If you decide to mill the heads try to eliminate the part of the chamber away from the valves but I am not sure you can mill the head that far this may leave the deck surface to thin , you will also need to mill the intake or the intake side of the heads so the intake will bolt on . You could also mill down the closed chamber heads .
Thanks for the replies. Rumblefish...if I end up replacing the cam I was thinking along the same lines, to use the Magnum cam. I think it would depend on what I get the compression up to, and I'd like to be at 9.5, which is still less than the original Magnum engines had. To make the best cam choice, I'll want to know the calculated CR, so I have some homework to do and I'm just getting started.
Chryco....I'm sure the pistons are "way down there", I was hoping that someone had already gone through a "build" like I'm proposing and could tell me what they did.
By the time I have the heads machined, install good valves, springs, seals, and rockers, the expense won't be too far away from a set of 440 Source Stealth Heads, which solves all of the head issues, so that is worth serious consideration if I can afford the extra money at the time. A complete rebuild including a set of pistons would be nice too, and before I know it, I may be up to $5000, which I don't have. So meanwhile, I'm going to see how cheap I can get to 350 hp and 480 ft/lbs of torque, which is enough for now.
Chryco....I'm sure the pistons are "way down there", I was hoping that someone had already gone through a "build" like I'm proposing and could tell me what they did.
By the time I have the heads machined, install good valves, springs, seals, and rockers, the expense won't be too far away from a set of 440 Source Stealth Heads, which solves all of the head issues, so that is worth serious consideration if I can afford the extra money at the time. A complete rebuild including a set of pistons would be nice too, and before I know it, I may be up to $5000, which I don't have. So meanwhile, I'm going to see how cheap I can get to 350 hp and 480 ft/lbs of torque, which is enough for now.
Chryco Psycho
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Except that Alum absorbs more heat & need yet another point of compression to offset the heat loss
TinCuda
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Just throwing this out there. This is your engine and your build but...
What is you end goal? It sounds like you are on a bit of a budget. It also sounds like you currently have a running engine and aren't looking to build it for racing. "I want to get the performance of the engine (8.2 compression) up nearer to 1970 non-Magnum specs,"
With this being said, and I know you don't want to hear this but, why not just use it as is?
If you are builting this engine for a show car, I am assuming this is a 'Cuda or Challenger, nobody will care what the exact horsepower is. If you are looking to build a hot rod, then you need to plan on dropping some cash on it.
You can get close to 5 grand real easy. You might as well just buy an overhauled engine at that point. There are outfits that will sell you a 350-400 horsepower 440 engine ready to go for right around 5 thousand.
I guess what I am trying to say is if it where me: Use the engine as-is and save your money, then later on after you have saved up some cash, buy what you want.
What is you end goal? It sounds like you are on a bit of a budget. It also sounds like you currently have a running engine and aren't looking to build it for racing. "I want to get the performance of the engine (8.2 compression) up nearer to 1970 non-Magnum specs,"
With this being said, and I know you don't want to hear this but, why not just use it as is?
If you are builting this engine for a show car, I am assuming this is a 'Cuda or Challenger, nobody will care what the exact horsepower is. If you are looking to build a hot rod, then you need to plan on dropping some cash on it.
You can get close to 5 grand real easy. You might as well just buy an overhauled engine at that point. There are outfits that will sell you a 350-400 horsepower 440 engine ready to go for right around 5 thousand.
I guess what I am trying to say is if it where me: Use the engine as-is and save your money, then later on after you have saved up some cash, buy what you want.
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TinCuda
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Now if you do want to shave your heads, you need to first check the head volume. "cc" Your 452 heads should be close to the 906 head volume of 88cc. Shaving the head 0.060 inch should reduce head volume by around 14cc. Of course if you shave 0.060 , then 0.084 must be removed from the bottom of the manifold and 0.060 removed from the sides. The pushrods should be .060 shorter also.
Without doing the math, it looks like you might be able to get this right around 9:1 compression and with the right intake and exhaust, make the horsepower that you are looking for.
OK, looking at the very rough math, I don't know what you have exactly but this should give you an idea...
You started out with 88cc heads with 8.2:1 compression. If you you shave 0.060 from your heads, 88cc-14cc=74cc. Lets say total head volume is now 75cc give or take. Going from 88cc to 75cc with a bore of 0.30 over and all else being equal, it will increase your compression ratio by 1.19 or bring your compression ratio to 9.39:1. You do not want to go much over that with cast iron heads anyway if you want to use gas from the pump.
If you replace your heads with aluminum ones, like Chryco Psycho said, your compression can be a bit higher. The aluminum heads like 440 Source Steath heads dissipate a lot more heat and a more ideal compression ratio would be in the 10.5:1 range. The aluminum heads typically have head volumes in the 75cc range which brings you right back to the 9.39:1 compression. (Edit: I just checked the 440 Source web site and the Stealth head advertised volume is 80cc. This would bring your compression ratio down even more,(9.16:1 at 80cc) but you get the idea of what I am trying to say.)
Again, this is very rough math and I just did it to give you an idea of what to expect.
Hope this helps...
.,
Without doing the math, it looks like you might be able to get this right around 9:1 compression and with the right intake and exhaust, make the horsepower that you are looking for.
OK, looking at the very rough math, I don't know what you have exactly but this should give you an idea...
You started out with 88cc heads with 8.2:1 compression. If you you shave 0.060 from your heads, 88cc-14cc=74cc. Lets say total head volume is now 75cc give or take. Going from 88cc to 75cc with a bore of 0.30 over and all else being equal, it will increase your compression ratio by 1.19 or bring your compression ratio to 9.39:1. You do not want to go much over that with cast iron heads anyway if you want to use gas from the pump.
If you replace your heads with aluminum ones, like Chryco Psycho said, your compression can be a bit higher. The aluminum heads like 440 Source Steath heads dissipate a lot more heat and a more ideal compression ratio would be in the 10.5:1 range. The aluminum heads typically have head volumes in the 75cc range which brings you right back to the 9.39:1 compression. (Edit: I just checked the 440 Source web site and the Stealth head advertised volume is 80cc. This would bring your compression ratio down even more,(9.16:1 at 80cc) but you get the idea of what I am trying to say.)
Again, this is very rough math and I just did it to give you an idea of what to expect.
Hope this helps...
.,
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TinCuda
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If you are going to change the cam, I would look at Comp Cams p/n 21-222-4, or 21-306-4, or 21-223-4 for stock engine builds. I am using a Lunati brand Vodoo cam p/n 60303. The Comp Cams and Lunati web sites have all the specs for their cams (If you go to thier web pages, it will save me a lot of typing. lol).
I am also a big fan of Rhoads lifters p/n 2018. (It is always a good idea to replace your lifters when you replace your cam.)
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I am also a big fan of Rhoads lifters p/n 2018. (It is always a good idea to replace your lifters when you replace your cam.)
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Chryco Psycho
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I think if you actually measure the block you will find it is taller than spec likely putting you in the 7.8 :1 range , swap to the iron closed chamber heads & you have 8.8 , use a shim gasket & mill the closed chamber heads & you should be in the 9.5 range or better . this is probably the best solution , it will be pump gas friendly but may detonate due to inability to create quench .
If you use the 906 / 452 head milled you might get to a real 9:1 .
If you use the 80 cc Stealth head the you drop 8 cc raising the compression to 8.6 range but with the extra heat loss to alum you lose 1 point back to 7.6 , mill the stealth head down & you should be able to get back to 8.4:1 ,not cool .
If you budget can take ti you can get the 512 stroker kit for the 440 , use the alum head , make close to 11 :1 compression , 10;1 with heat loss to alum & still have proper quench to kill detonation & be pump gas friendly
If you use the 906 / 452 head milled you might get to a real 9:1 .
If you use the 80 cc Stealth head the you drop 8 cc raising the compression to 8.6 range but with the extra heat loss to alum you lose 1 point back to 7.6 , mill the stealth head down & you should be able to get back to 8.4:1 ,not cool .
If you budget can take ti you can get the 512 stroker kit for the 440 , use the alum head , make close to 11 :1 compression , 10;1 with heat loss to alum & still have proper quench to kill detonation & be pump gas friendly
Ah, more great replies, thanks everyone. Tin Cuda, my goal? 350 horsepower and 480 ft/lbs of torque was the original goal. But I think I would have a hard time drawing the line once I got into either the heads or the bottom end very far, so actually, running the thing as-is to start off with isn't bad logic at all. And yes, I'm on a pretty tight budget. And I might even be content with it for the long term. I had a non-Magnum 383 in a 4400 lb 1973 Charger and I wasn't chafing at the bit to improve it, so maybe I would be OK with the low performance 440. I don't know, I've never run any level of 440. All I know is that big torque makes me grin, and I'm far more into that than I am horsepower and redlines anyway.
My engine appears to be in beautiful shape, no sludge at all, and the inside of the rocker covers are shiny silver metal, and that's as far as I've been so far. I'll check the mains and rod bearings, have the 452's checked, and install them with thin gaskets at the very least. This will go in a converted to 2WD Jeep YJ Wrangler which will weigh about 3000 lbs, and be occasionally bracket raced. I'm probably a blasphemer for talking Jeeps but I posted here because my all time favorite car was a like new 1973 340 Rallye Challenger that I owned back in the day, and Jeep forums don't seem to talk 440 Mopar very much. Thanks everyone.
My engine appears to be in beautiful shape, no sludge at all, and the inside of the rocker covers are shiny silver metal, and that's as far as I've been so far. I'll check the mains and rod bearings, have the 452's checked, and install them with thin gaskets at the very least. This will go in a converted to 2WD Jeep YJ Wrangler which will weigh about 3000 lbs, and be occasionally bracket raced. I'm probably a blasphemer for talking Jeeps but I posted here because my all time favorite car was a like new 1973 340 Rallye Challenger that I owned back in the day, and Jeep forums don't seem to talk 440 Mopar very much. Thanks everyone.
Chryco Psycho
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sounds like fun
GranCuda70
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If there was a popcorn Icon I would be using it !!
TinCuda
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I am hoping he just puts the engine in and runs it as is.
If not, we will be here to help.
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If not, we will be here to help.
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OP_Mopars
Member
This is what $5000 looks like - full roller motor built from a $250 '67 440 junkyard turd (lots of 440Source parts used).
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