Building low compression 440 (first post)

Hi, this is my first post on this particular forum. I recently purchased a 1975 440 and 727 torqueflight out of a Chrysler imperial. During stripping the engine down to the bare block, I was surprised to find the engine has little internal wear what so ever. No ridge in cylinders at all. Due to the low compression of this 440 (most likely 8:1 compression), I'm questioning what power I can make with an intake, carb and cam swap. The motor is going into a 84 dodge Short box 4x4 pickup with 3.55 gears and a auto trans. The truck weighs about 5000 lbs give or take. I would like to make 375 hp or slightly better. Any advice? Thanks for any input

Welcome to the forum

Are you just planning to re-ring, hone and reassemble? Now would be the time for better pistons. Actual CR may not even be 8:1... What's the budget?

In a 5000 lb truck I'd recommend a short cam with lots of low-end torque. 375 hp should be easy from a 440.

Do you have a budget?
Closed chamber heads and thin head gaskets are a good start.

I am on a budget. I would say im willing to spend 3,000 on this engine. Im looking to re ring/re bearing and re assemble this engine. Have a set of 250# casting heads I'm looking to possibly use. If i can find a set of 915# castings, it will opt for those with aluminum heads being out of the question.

Best bang for the buck will be just cleaning it up and running it. Dont go changing rings and bearings. If it turns over freely now, we can postulate it will run ok. In other words, these rings and bearings are seated and should work fine now unless a bearing is spun and your screwed anyway. Sounds like you have a perfect candidate for just bolting on a few things. Compression ratio will suck, but changing pistons is money and you will end up figuring out it has some taper to it and want to bore eventually. Then standard hi comp pistons are garbage to you.

Another member recently tore down and engine and spent some money, on a budget, then had to spend more since you basically cannot just tear into one and piece meal the thing. You might find that thread, i think it was 71adam440 or something like that.

Pick your cam and a good timing set. Then look to the heads, maybe do a valve job or guides. You could find a set of 915 heads sure, spend money on them, then trash them later when you decide on a full rebuild and aluminum heads. That's just cash burned for a small improvement.

If you go the low buck route(many people have done these), plenty of budget becomes available for other parts of the truck. You'll soon find things to spend on. Or buy new rings and bearings now and buy them again for the full rebuild, which could be as soon as something goes awry doing a rering and bearing job.

For your deal and budget I would look at using a set of 440 6 pak forged pistons with new rings, bearings and a better camshaft and timing set. You should have the new parts balanced to that crankshaft and balancer so it doesn't shake with the new parts Make sure and use that original torque converter also as those motors are externally balanced by using weights on the converter and balancer.
Good luck, let us know what you decide to do

I found a 1973 440 MH engine and trans on the Tacoma, WA CL for $100.00 and beat 5 other guys to the seller to pick it up. It had been bought from a wrecked MH 20 years earlier and stored at a body shop, covered up and it looks it . It is sitting in my shop now and when it warms up around here, I will pull the spark plugs, drain the oil and examine it, if it passes I will give it 4 qts of fresh Walmart 10w30 oil and spin over the oil pump with my 1/2" drill motor while I turn the motor over with a breaker bar at least 2 or 3 complete revolution and check a mechanical oil pressure gauge to see where it falls. If it looks good then I will do a compression test while it hangs on the cherry picker (it came assembled with starter, alternator, ThermoQuad, etc.) Parts alone are well worth the $100.00 and it is for a club project rat rod so expectations are not high and the chassis is a model A frame with a T-Bucket body, so it should be fun for all.

Hey somecarguy that was I. I ended up spending over budget because I found some bad bearings, and decided to re ring and re bearing. That was inexpensive, but when I got the bright idea to use an autozone tool to get rid of the ridge at the top of the cylinders, I messed them up good. So, i had to have the block bored, and since I was already shelling out for block work, I got the crank ground and then figured I may as well get new rods and pistons.

Basically I learned that with good used short block, with at the most new rings, bearings, and drill hone, all you need is a pair of sidewinder or 440 source heads, aluminum intake, good carb, cam, possibly new pushrods and lifters, and you can have a 400+ hp engine for about $2000

http://www.forabodiesonly.com/mopar/threads/dyno-testing-a-stock-1972-440.249866/

A very good read!

Don't worry about what it might make for hp.
Just use the appropriate parts for the application and it will make what it makes.

As mentioned, keep the cam duration pretty short.

The 250 heads are a one year only, sort of odd ball deal.
They are essentially open chamber 516 heads with 1.74 exhaust valves.
So, they have the underwhelming 516 intake port.
Not really an issue for this type of build.
A little bowl work and a decent valve job would be worth it IMO, along with machining for posi-seals and setting them up with an appropriate spring.
Look the exhaust seats over good, if they're pounded out pretty wide, for that application, I think hardened exhaust seats would be a wise move.

Probably outside of your budget, but IMO the best way to update that short block would be to change the pistons to some KB quench domes.
It's really the best way to gain the compression and not grossly adversely affect the octane requirement........ Other than flat tops and closed chamber heads.

Thanks for all the input everyone. I'm looking to stay away from the machine shop in this one. The link that kowalski440 posted contains an interesting buildup, sort of what I'm going for. To summarize the article, they used an m1 single plane intake, headers, 850 cfm carbs, 516 heads. Made alot power surprisingly. I'm going to run a dual plane intake, a decent carb (850 seems a little much, not sure if my 440 will run that carb without being super rich), and either a .509 purple cam or the .484 lift can. A good port job on the heads as well to insure good flow (If a set of 915# casting come up, I will snag em, but otherwise it's the 452# or 250# heads I have.) And a set of headers as well.

Have your heads milled to increase compression a bit.It can only help.

I have a 75 Newport with a stock rebuilt 440.Runs fine.Maybe I will get off my butt and put my C body 1 3/4 Hooker headers on there as well as the Performer intake and 750 vacuum secondary on the shelf.Probably have a small cam I can throw in there as well.With the 11" converter(on the shelf) and 3.21 limited slip in the 9.25 I can be blues brothers fast.

I understand that we're all working w/in a budget, but keep in mind that not doing the proper machining where required isn't a good idea. There's "budget"... and there is "short sighted". Just my , naturally.

Remember you have low compression, (I assume) a stock converter, 3.55's and a 5000 lb vehicle. I do not think you'd be happy with the .509. Even the .484 may be too much...

As said I would (highly) reconsider your cam choices. You have a 5000 LB vehicle and you need low RPM torque. Your actual SCR is in the 7's likely. You are already torn down to the bare block & I would rebore & get it in the 9's and you might be able to get some pistons close to what yours are now so no rebalancing needed & HF has a gram scale for that regularly on sale for $9.99 & it was just as accurate as my buddys' high dollar one. or even drop in some std ones if on a real tight budget. Some file fit plasma moly rings in an overhaul kit (bearings/gaskets etc). (you can file fit em with a point file).

I agree, either of these cams will make a pig out of your truck, way too much duration for the application.

I agree I had a 84 4x4. Never could get a big enough cam in my hot rod so I put a purple shaft 484 in my 360 big mistake it sounded great it was a pig

For that application, I think you should be looking at something like a Comp 268h or similar.

OP, I hate Mopar grind cams, especially the famous .484 They are a old design in the mid 1970s and now outdated
Step into the 2000s and buy yourself a better cam
All OEM non Max wedge BB Mopars are starved for air and fuel through the stock heads
IHTHs

What about something with 250-270 duration or slightly less, or will this be too much? How much lift? I'm settled on a dual plane intake, probably eddy performer rpm and a 750 Holley carb. I have also considered putting 4:10 gears in to help as well. Am currently running 31 inch tires. Also, there is no machining to be done here. I doubt my particular engine has even 30,000 miles. The truck right now has a warmed over 318 (eddy 600 cfm carb, performer intake and cam, ported heads, headers) that is crippled by low compression as it sits. Makes no torque in all reality, but pulls good above 3000 rpm. Would like to keep my stock converter, or go with a slightly better one. Will it be a night and day difference from the 318?

Do you know how many miles are on the motor? If it's in that good of shape I would leave the bottom end alone and focus on the top. $3k budget?

440 Source heads: $1k
Used dual plane: $120
Headers: $150
Used Holley: $150
Cam set: $150
Rear sump pan: $150
Mounts: $100
Gaskets: $100

I know you said you weren't considering aluminum heads, but after freshening up a set of irons you're halfway there and you still need to deal with the compression issue.

I had the same experience with the 284/484 hydraulic cam that I put in my '64 Polara with a fresh 440. You need a looser than stock converter to take advantage of the cam off the line and my converter was stock '64 and tight. It had a great top end once you got over 60, but below that DOGGY

Have the bores checked with a dial bore gauge for wear and taper before deciding to re-use the stock pistons. How do the main and rod bearings look, how much clearance? Do the rings rotate freely in the piston, or are they all carbon up?
Are you re-using the stock rod bolts, or replacing them and having the rods resized?
Inspect crank journals and crank run out and straightness in case the crank needs re-ground and bearings to match.
What condition are the cylinder heads seats, valves and valve guides?

I guess if it was me, and had a good short block, then I would leave the short block alone and put smaller chamber heads on the engine.
If you used something like the 78cc Trick flow heads, that should put compression around 9.5:1, already have new everything new including springs for aftermarket cam. That would kill your budget because of the cost of the aftermarket rockers arms, and hardware, but give you room to make alot more power later when you can afford to build a stronger short block.

I wasn't recommending to follow that exact build, was just pointing out to show that low compression isn't that big of a power killer in a bottom end
power build. But the cam choice is critical, though.

Listen to what fast68plymouth is telling you.

I would opt for the regular performer or a CH4B if you can find it .

The original compression ratio for that engine is right at 7.2:1. It's been calculated a zillion times here. The piston is down in the hole about 0.180".

Increasing the comp ratio from the original honest 7.2:1, to 9.5:1 increases power output by 8.7%. So a 350 hp engine turns into a 380 hp engine with no other changes.

The original 440s were dynoed and at the standard conditions of that test procedure they would make 335 hp. That is per an interview with an old Chrysler guy in Mopar Action years ago.

I agree with whoever said first thing is to buy a new set of Stealth heads. 440Source has one pair in their clearance section for $750 delivered. Those heads are worth up to 90 hp over stock cast iron heads.

Now that flow is taken care of, compression is next. The Six Pack pistons will get you to about 9.5:1 compression, maybe a little bit less. But they will also give you squish which will help by reducing negative work.

If you cant find a set of those then using the data from another post, look for original pistons for a 1967 or 1968 HP 440, they'll at least get you into the mid 8s.

With a heavy truck and low compression you need a short duration cam that closes the intake valve early. Either the .484 or .509 cam is way too big. XE262 Comp is as big as I'd go.

R.

PS: Thanks to Polyspheric (I think) for this useful page:
http://victorylibrary.com/mopar/otto-c.htm

Stick with the 262 - 268 cams, Performer (not RPM) intake, and put it back together.
Save your pennies for a set of pistons and heads.

That will get you by and give you a significant torque increase over that gutless 318.


Just for giggles, I dynoed my 72 Imperial with it's bone stock California spec 440. Popping off the factory air cleaner pushed me up to a whopping 199 rear wheel hp and 294 lb/ft.

It was rated at 225 hp and 345 lb/ft so I think it was doing pretty good.

Sliding in a cam perked it up but the timing gear let go before I got it back on the dyno.

You can make 375hp with that 440 but you won't like the way it runs in your truck.

I've built a smogger 440 just like yours. I put a mild cam in it and a set of 440 source heads. It still didn't have the bottom end power I wanted and that's in a car, not a truck. To get the smogger 440's to haul you need a decent torque converter and some aggressive rear gears. I started with a 3.55 gear and a stock converter and it was not near enough. And your truck is probably 1000lbs more than my car was.

I would clean up the engine, regasket it, install a new timing chain set if it needs it and run it. Recurve the distributor and dial in the carb of your choice. It won't have 375hp but it will run, tow and 4x4 well.

I built and dyno'd the 440 engine that kowalski440 referenced you to. There is no way I would suggest you run the 509 cam we used. The best truck engine I ever had was a bone stock 440 out of a 1973 Chrysler New Yorker. I used it in a 1 ton welding truck and towed some big trailers with it at the same time. Don't use the 250 heads as the 452s are a better head, clean them up and run them. The 452 heads are easier to get flowing for the amateur porter and will get better flows than the 250 heads. Keeping the stock pistons I definitely wouldn't run a cam any bigger than 220 @ .050". A stock cast iron 4bbl intake manifold from 1968-1970 works fine in a truck application. Use the CH4B, or the Performer RPM if you must.