I bought a used set of pistons and rods just for the rods. The pistons were dished out and supposedly came from a mid-70's motor home engine. I doubt that the remanufactured motor would have those but I agree with you, it's really easy to pull the head and check it out. He sounds inexperienced but should be able to find someone who can help show him how to do it.

Every Badger 440 piston I have heard of has been a stock replacement mid 70's piston. And since that's how they said they built it, you will have about 7.8:1 or so compression. You will have to pull a head and measure to be sure. You remove a head, rotate the crank until that piston is at the top of its travel and use a caliper to measure how far down in the hole it is. Sounds to me you have a 99% chance of it being a mile in the hole 70's smogger piston. I would measure the overbore and order new pistons, have them installed on your rods and have the assy balanced. You will be miles ahead if you do this instead of using those low-cr pistons. They should just stop making those crappy low compression pistons but the mass rebuilders just keep buying them for their cheapie rebuilds. I would probably go with a set of KB237 pistons.

They may not be a low compression piston but probably are I'd it's a 74 spec? Badger makes a good piston. I think they may have been a vendor to Chrysler for years? I had to get a couple of +.020 factory replacement pistons for my old A12. They were Badger and I heard they were the original vendor? They looked the same as my originals.

the Guy at the rebuilding company sd that they use the flat top pistons, however, i guess i will need to pull the head to find out what is under there, thanks for all the input and i will post update once i pull the head and find out

with the oil pan already off the motor, i have the motor on my engine stand, can i turn the motor upside down on my stand and try to get some part numbers off the pistons? or check the rods to find out what is there?

Nope

i already have a forged crank from a D-440 block, i also have the rods, i really want a better compression engine, i already have a 73'motorhome motor in my car now, i was trying to get a more correct motor for my car, i think i will take my crank to the machine shop and see if it is any good and also pull off the head to see what i have for pistons and then i guess i can make a better choice, i really do not want to sell this motor then because of the lack of motors around my area, Jackson MS, i have a good starting point to build a good street motor
thanks
Randy

There are lots of flat tops.. Some will give a true 10.5 C/R & others will only give a 7.8 it depends on the compression height of the piston... When you pull a head bring a piston up to TDC & measure how far the piston is down the bore... To accurately measure this you need a few special tools but you can get a reasonable measurement with straight edge & a feeler gauge...To get a true 10.5 with 88cc heads on a 440 would require the piston comes up to exactly flush with the deck surface of the block and a thin head gasket... Very few do.. A piston .150 "in the hole" and a normal head gasket gets you 7.8... BTW .150 is just a little over 1/8th" or about the thickness of two nickels...

thanks RoadRunner JD, i really did not want to hear this, but after 3.5years of this project nothing surprises me anymore, this project has really tested my patience, coming from chevy to mopar has been a really learning experience, however once i have the mopar built, i will have something, the chevys are dime a dozen, i just hope i do not have to cash in my 401k to finish it

hey Randy,

i knew you wld chime in here sooner or later, i appreciate you input , guess it is back to the drawing board on this deal

i most likley will change out the crank and pistons

thanks for the 101 on Cast vs Forged!

thanks JohnRR , i will post my findins when i pull the head, i have go a better of mine that can help me pull the head, i do not know when i can do this, however, when i do , i will post my findings

Now a dose of reality... With 906 heads to run 10.5 C/R you'll likely be mixing race fuel to keep from detonating... Open chamber iron heads are not your friend.... But since you have fresh 906's I wouldn't be changing them... But I would consider having them milled.. Take the heads off & get us a number... If the pistons measure .090 in the hole & you cut the heads .050 & use a thin gasket you'll be around 9.5 which with open chambered iron heads is right where you want to be... Get a depth & get back to us..

i will do this, thanks for the tech

More info always helps.
What is the engine going into?
What is the application? (daily driver, street, performance, race?)
What transmission, stall speed, rear gearing, tire size?
What are your performance expectations?
What are your budget expectations?

Also, you don't have to pull the heads. You could turn the engine on the engine stand to where the spark plug is the highest point. set the piston to TDC (both valves closed or remover rocker arms), and cc the chamber volume directly by filling through the spark plug hole.

Assuming a 0.030" over bore (4.350" bore x 3.75" stroke) the piston swept volume should be 55.73 cid = 913.44 cc's.
Here is a list of chamber volumes above the piston at TDC and what the compression ratio would be:
CC's CR
90 11.16
95 10.62
100 10.13
105 9.70
110 9.30
115 8.94
120 8.61
125 8.31
130 8.03

You would want to cc the chamber using some oil so it won't run past the ring gaps, or cause rust in the chamber/bore.

What is the engine going into? 68'dodge coronet

What is the application? (daily driver, street, performance, race?) street car

What transmission, stall speed, rear gearing, tire size? 727/stock convertor/ 3.55 275/60/15

What are your performance expectations? good sounding driveable street car

What are your budget expectations? cheap as possible

so i wld measure out the cc's of oil it wld take to fill up the #1 cylinder at tdc on the compression stroke, and if my motor is bored 30over i wld use the chart you post?

here is a pic of car