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+--- Thread: Upping Compression ratio -440 (/showthread.php?tid=615)
Upping Compression ratio -440 - Piper - 03-19-13
been mulling over what to do with the 440 I have
I want to bump the compression up to about 8.7 from 8.2 (I have 915's for it, haven't blueprinted them but sounds like factory they went out at 80cc)
its a std. bore '72 440
Pistons sits .17 in the hole
I do have a mechanical .528 which a lot of research has lead me to the conclusion that the small duration has great vacuum characters as well as with the fast ramp it should fill the cylinders quite rapidly (seems to be a good fit for a low compression motor)
I would like to squeeze just a half of a point of compression more and thought milling the heads, but I cant get the math correct.
what should the heads be milled at, and how much should the intake runners be cut? (I have adjustable's so I should be good in that dept)
Upping Compression ratio -440 - Piper - 03-19-13
Well I think I lucked out, we did the DIY cc'ing of the heads, and they came to a couple drips over 73cc for the chambers that were spot checked
should put me around a 8.5:1 with a .020 head gasket
at least it will favor the crappier gas!
Upping Compression ratio -440 - 4264door - 03-19-13
I'm sure you'll be happy with that.
Upping Compression ratio -440 - 67r/t4speeder - 03-19-13
8.5:1 would be nice right now, even so called premium is not up to par anymore for Max. He's been getting a bit grumpy lately and I know what it is. Lucas octane booster isn't helping either.
Upping Compression ratio -440 - Piper - 03-19-13
reading more I am seeing guys with 8.5 motors in the low 13's and even in the 12's with a good set of headers convertor and exhaust
Upping Compression ratio -440 - 67r/t4speeder - 03-19-13
I am sure having aluminum heads will help ???
Upping Compression ratio -440 - Piper - 03-20-13
they certainly would...this is for the Charger I bought the short block years ago( low miles) and I am just determined to drive it since its already together
someone put a HP pump windage tray and gear drive (don't know why ..but hey its there going to run it)
the aluminum's have a huge advantage in every way except the bigger cc chamber (I could have them cut, but then have to figure out what that math would be)
the big money is going into a undisclosed motor for the 67 Net
Upping Compression ratio -440 - 4264door - 03-20-13
Ah-hah! A stroker...I could just feel it! Run on lousy pump gas, gobs of torque and totally streetable but when you mash the loud pedal...you KNOW you got sumthin' big under that hood! Come on...spill the beans for us. How many cubes?
Upping Compression ratio -440 - 67r/t4speeder - 03-20-13
Piper Wrote:they certainly would...this is for the Charger I bought the short block years ago( low miles) and I am just determined to drive it since its already together
someone put a HP pump windage tray and gear drive (don't know why ..but hey its there going to run it)
the aluminum's have a huge advantage in every way except the bigger cc chamber (I could have them cut, but then have to figure out what that math would be)
the big money is going into a undisclosed motor for the 67 Net
There was a Pete-Jackson gear drive in my 426 for a while, I am sure it was fine but I got nervous thinking it might come apart, or wearing through the cover ??some day so I took it out. Probably would have been fine though.
I would like to try a good quality set of aluminum head's someday, if I could ever afford a set. I have installed many Brodix head's on customer car engine's I build and never had a lick of problem's.
Are you going with those Cometic gasket's?
Upping Compression ratio -440 - Piper - 03-20-13
on this motor? nah just a .020 steel gasket
on the "other motor" definitely!