i used the same sealed power pistons in 2 different blocks, (only on the stand). the first block, which i am not using, my deck was at .180

the block im using now is .210, and the deck varys by a few thou by each piston.

what gives? the 2nd block does look to have been decked before, but its larger? even larger then factory deck?

is this thing going to run like a dog, its only a stock motor with a oregon #125, i have yet to check the cc's, but i know the head has been cut atleast once in its life. (could be hope for small chambers)

what gives?

piston compression distance is 1.740



does this look like the deck has been shaved before? (front dowel pin looks very short, and a little smashed, like it was pounded back in.)

Machining tolerances were not something the factory seemed to spend a lot of time on with the Slant motor, especially deck height. I have seen deck heights anywhere from -.150" to -.250".

To me, that block does not look like it has been decked.

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Official Cookie and Mater Tormentor.

Do these motors have problems with such a large negative deck? I know for a vw, it will be more likely to detonate, a vw motor loves a .040-.060 deck

When I get home ill check the deck for straightness with a flat edge and deeper gauge, I can't remember what the max number for imperfection is, is it .006? I have a great feeling its flat though, decks usually don't have problems, and my deck gauge read pretty much Zero all around the surface

Yeah, .040-.060 is the optimum quench that most all engines like to have. You either throw down for custom pistons, or longer rods or put the head on go. Doesn't really give you much choice. What are your driving goals for the engine. Is it going to be primarily a street driven car or something else.

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There's no such thing as too much cam....only not enough engine!

The SL6 has an open chamber head so the deck height only impacts static compression & DCR.
Mill the block & head to get the DCR you need with that cam.
DD

its just a stock car. used for... well what a car should be used for

i am confident that the head is pretty damn flat. there was only small area where a .002 feeler went through, but not even the .0025. every once in a while, i was able to see the smallest faintest light between my straight edge and deck. but never would a .002 fit. i really need to find my starrett straight edge, and i could be %100 confident.

so if i dont like my CR, when i find out my CC's, the deck is just out of the question, i cant afford to remove everything ive assembled AGAIN. but i still have the deck on the head. how much can i remove before anything is needed. is there a CC amount thats the max amount to remove before pushrods are needed? or did mopar vary the cc's as well? and is impossible to tell?

what is the typical CR for just a normal daily driven car you guys use?

even if this is a stock rebuild i would take .110" of the block while you have it out, it is not going to hurt anything.just clean and wash the block with water don`t hot tank it.with that much clearance your going to be under 7to1 comp, thats no good for any kind of performance.

Yes, a pretty common situation with "later" 225's
So if you do the calculations with what you currently have, using a 58 cc chamber, a .045 thick head gasket and 50 degree IC... you get 7.5 static CR and a 6.6 DCR... a real "stone" performance wise but that combo would run on the worst of fuels and be OK with lot's of spark advance.

TL just gave you part of the common 225 "recipe"... .110 block deck, combined w/ 54 cc head chamber and a .045 thick head gasket. That gets you 9.1 static and 8.0 DCR... add a steel shim gasket and things get even "spicier".
DD

i have just cc'd the head, and its right at 55cc. and also im using a felpro gasket which i have read is a .038 compressed thickness? and the gasket diameter on a felpro gasket is 3.5420

this leaves me with a ratio of 7.80:1
even with docs .045 gasket number, is still 7.72:1

like i have said before, im not looking for a performer. im looking for a motor, that will run great, and last a long time doing so.

and i know for a fact these cars run awesome when, they are actually complete $#!+, via my motor before i pulled it. with broken rings, and VERY sloppy timing chain. with out valve adjust. i was happy the way it drove, good torque, had great pickup, and idled and drove like i thought it should have. i cant wait to get this thing going again.

but i am still curious, are there still any NaySayers about 7 3/4:1 compression, for what im looking for? the man josh skinner by the way who recommended the #125 cam, said no less then 7.5, so looks to be im within the right.

I'd run it and dial your timing up to make up for the lower compression...

It will work fine as a daily driver, and you can run the cheapest gas in town without worry of knock...

It should get you from here to there reliably and that is what you are building it for...later, when your bank account recovers...take your spare block and build the 9.0:1 SCR "next step"....

-D.Idiot

After upping my compression on my daily driver, I would never consider running that low a compression ratio again. My car is heavy (3300) pounds and the extra torque and spunk makes the car really fun to drive. Mileage is great on regular and even better on mid grade. It is fun to bust both tires loose at a light or have it immediately crank up as soon as I touch the key, even on a super hot day. The engine no longer performs like a slug, gets great mileage and is a blast to drive!

Set up is listed at the bottom. Pictures can be found clicking on the red link below my name.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

my vw is my fast high compression car. 10:1, high 11's in the 1/4 mile. so im fine with a slow6 thanks for all the help guys. you guys are cool as hell

no reason you should leave easy power and MILEAGE on the table for such a simple thing as milling the head...

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1965 Plymouth A/FX 512ci (under construction)
1968 Dodge Dart SL6 14.25 @ 91.5 1.91 60'
1973 Dodge Dart SL6 Stock
Killer Bee's Member Since 09'
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