fordmugg

tex,

i will check the block today and post the info on where it was reman at

firehorse5_0

I have a '70 351 short block with the round dish pistons. I had no idea they were kind of rare. Learn somthing new everyday.

fordmugg

ok got the block number D0AE-6015 and it was re manufactured at ATF

Tex

Well, that means your block is an early casting with a 9.48" deck height. Keep in mind if could have been decked during rebuild and might be slightly shorter.

But more importantly, you need the head casting numbers. They are on the underside of the head. It's this number that will be of most importance determining your current compression ratio. Being a reman engine, just because it has an early block casting, doesn't necessarily mean it has early heads to match. Do you happen to have any pics of the underside of the heads before you installed them or did you write their numbers down perhaps?

Otherwise, the only way to answer your original question is to pull a head and verify it's casting #'s and therefore it's chamber volume. While you've got the head off, you can measure how far down in the cylinder the pistons are at top dead center. Next, you can get some exact measurements on the dish size in your current pistons too. Only then can we accurately determine what compression ratio you truly have right now and if swapping pistons is what you really need to do. Keep in mind that just because a piston or head is advertised to give a certain compression ratio, doesn't mean that's what it actually gives. The only real way to know is to measure.

Also I couldn't find anything on ATF reman engines. Did it perhaps say ATK?

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1964 Galaxie 4dr 351W Daily Driver, 1967 Galaxie fastback 460,
1969 Montego MX 410, 2 x 1977 Grand Marquis 460 & 400, 1979 F150 400

fordmugg

im not sure about the numbers on the heads....and yeah sorry it was ATK....i put the wrong last letter..lol

PSIG

While there is a slim possibility they are 302 heads, most likely they are 351 from a production rebuilder. Assuming that, if it uses large spark plugs (18mm) then it's the C9OE/D0OE style heads. 14mm plugs means later larger chamber heads. FWIW

David

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-=≡ If it was easy everyone would do it ≡=-

slik

I am asleep and have a headache after reading all of this. I may have missed something, but whenever you are putting an engine together you balance should you decide to. Not a big deal no matter what piston you use? Was someone stating that factory pistons can't be balanced. If not, this is new to me because I was planning on doing just that with a set of forged trw pistons that I pulled from a 302. Had them bead blasted and ready to go. Everything was in good shape so crank will just get a polish,and the block will get a good bath and rehone.

Next, although balancing may not equate to more power, I do believe balanced engines run better and there are other benefits of balancing.

DanH

any piston can be equaled in weight for balancing , oem or aftermarket . MY question on balancing with TRW's forged piston that are know to be ... somewhat heavy than oem , sent to be bal. don't come with heavy metal in the crank . another ? ...HOW Can that be ?

PSIG

I assume your question is in jest Dan. There are a number of methods to maintain a given balance in the assembly without heavy metal - up to a point. What are you getting at?

David

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-=≡ If it was easy everyone would do it ≡=-

DanH

not in jest . you ever have a stock engine balanced ? then you would understand if attension was payed to what was done . simple .... trw pistons , stock rods(only work done upgade bolts/resizeD) stock crank plus stock damper/flywheel. piston/rods just equaled in weight. what was done to the crank to balance ? to make it easy NOT A LOT EDIT: add .. what does that tell about the 100,000 mile oem balance

PSIG

Hmmm... I'm not sure I follow you or how others are comfortable doing it, but any combination of rod top-pad weight removal, lighter piston pins, piston boss shaving, rod lower pad reduction (at half the weight factor), or opening/chamfering the crank journal ID (drilled area) also at half factor, would be some examples of how the balance grade could easily be maintained without compromising crank end-to-end balance or adding heavy metal. How do aftermarket forged pistons and all that figure in with a 100K-mile factory balance? Sorry dude - not following you here. What am I missing?

David

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-=≡ If it was easy everyone would do it ≡=-

DanH

you will have a hard time to follow when you never done it . No need for all the labor the average guy takes his parts to be balanced , the balance shops up the price for the way you said .. Who said all the extra work was needed ? Edit, Forgot about the forged pistons and 100K mi. I never said anything about forged pistons in a 100k factory showroom car . you did on warrenty and factory balance on stock engine going 100K mi.. I'll add it up for you , oem balance is'nt that great , thats why pistons that are heaver (TRW) can be used.

68sportcoup

what about a cam designed for low compresion posibly a custom.
just a thought less work and money than a tear down with a rebalance.


or a turbo.

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68 falcon sport coup 289 toploader 9\" 390\'s detroit locker
68 falcon undergoing v8 swap
67 falcon 351w auto
68 falcon fact ac
67 falcon next project no motor or trans no rot either

Mushfik2011

who knows if 4V 10.7:1 pistons will work in a 9.00:1 pistoned 2V motor or will the change require different rods/valve clearance? I am searching to solve it but can not find it.

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palm beach used cars

DanH

you can find the pistons , no problem , use them . same rods are used