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Re: Building low compression 440 (first post) [Re: Benson] #2211368
12/10/16 06:04 PM
12/10/16 06:04 PM
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Posts: 4,452
Michigan
MarkZ Offline
Worthy
MarkZ  Offline
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Posts: 4,452
Michigan
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.


1987 Fifth Avenue - 512/518/D60
Re: Building low compression 440 (first post) [Re: ragin sonny] #2211371
12/10/16 06:12 PM
12/10/16 06:12 PM
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Graham, WA
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Polarapete Offline
top fuel
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Graham, WA
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 down


1986 Dodge Ramcharger 440 2wd, Bracket Racer Under Construction
1998 Ram 2500 QuadCab, new daily driver.
2008 Honda Element
2014 Carry-On 7x14 Cargo Trailer
Re: Building low compression 440 (first post) [Re: Benson] #2211383
12/10/16 06:37 PM
12/10/16 06:37 PM
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Posts: 5,399
Aurora, Colorado
451Mopar Offline
master
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Aurora, Colorado
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.

Re: Building low compression 440 (first post) [Re: Benson] #2211404
12/10/16 07:30 PM
12/10/16 07:30 PM
Joined: Apr 2014
Posts: 129
SE Indiana
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kowalski440 Offline
member
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SE Indiana
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.

Re: Building low compression 440 (first post) [Re: Benson] #2212650
12/12/16 06:06 PM
12/12/16 06:06 PM
Joined: Jan 2003
Posts: 75,095
A Banana Republic near you.
JohnRR Offline
I Win
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I Win

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Posts: 75,095
A Banana Republic near you.
Originally Posted By Benson
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?


Listen to what fast68plymouth is telling you.

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


running up my post count some more .
Re: Building low compression 440 (first post) [Re: kowalski440] #2212655
12/12/16 06:14 PM
12/12/16 06:14 PM
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dogdays Offline
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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

Last edited by dogdays; 12/12/16 06:15 PM.
Re: Building low compression 440 (first post) [Re: Benson] #2212775
12/12/16 09:30 PM
12/12/16 09:30 PM
Joined: Jan 2003
Posts: 28,071
Irving, TX
feets Offline
Senior Management
feets  Offline
Senior Management

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Posts: 28,071
Irving, TX
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.


We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind.
- Stu Harmon
Re: Building low compression 440 (first post) [Re: Benson] #2217129
12/19/16 06:10 PM
12/19/16 06:10 PM
Joined: Feb 2003
Posts: 21,318
Manitoba, Canada
DaytonaTurbo Offline
Too Many Posts
DaytonaTurbo  Offline
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Posts: 21,318
Manitoba, Canada
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.

Re: Building low compression 440 (first post) [Re: Benson] #2217218
12/19/16 08:20 PM
12/19/16 08:20 PM
Joined: Oct 2011
Posts: 559
Idaho
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LaRoy Engines Offline
mopar
LaRoy Engines  Offline
mopar
L

Joined: Oct 2011
Posts: 559
Idaho
Originally Posted By Benson
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.


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.

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