Specs please

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deyo21

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Hello,
Does anyone know the CC rating of a 225 head. Also what is the top of piston distance to the deck at TDC.
Thanks,
Jason
 
you can mill the head .100 and still have clearence, i believe u get 9.1-9.5-1 cr after that. hope that helps i'll look it up, also check on slantsix.org
 
Thanks for the post. Didn't take the time to cc the head myself. Block and head are getting cleaned right now. Just trying to crunch some numbers. I want to end up in the 9.5 range. Question? I assume you have done a slant 6 or two. What kind of intake/ carb setup would you recomend? It came with a single, I'm for sure going to go to a two. Think that will work?
 
Dis. Year CR. hp tq
225 1964-1971 8.4 to 1 145 @ 4000 215 @ 2400

just look around on that link you will get a 'ballpark' figure from similar years, id mill the head .100 and that would bump up the cr alot and more power, what are your plans what do you want out of the motor?

edit: ok i read ur above post lol posted it it right after you commented. Well i never did get a chance to build my slant:( but i did ALOT of research when i was into it, with some good head work that will unleash ALOT of power and such aftermarket pistons n such, alot of people go with the offy 4bbl intake off summit Its a lil pricy and either a holley 390 or a eddy 500, the eddy to some and from what ive read is easier to tune if your new to that area.

http://store.summitracing.com/egnse...sults=false&Ntk=KeywordSearch&DDS=1&N=700+115
there is alot of good parts off summit. again check slantsix.org they REALLY good on slant stuff...obviously :lol: anything you want done can be...with enough money :p wow i see now after looking at the link they dropped alot of there slant parts :( they use to have ALOT more

go here instead more stuff
http://store.summitracing.com/egnse...0+4294840127+115+4294888961&SearchType=Engine

small engine.JPG
 
Most slant heads run around 50 to 58cc and the pistons average around .200" down in the hole at TDC. Ma Mopar wasn't too picky with tolerances when she was spitting out slants, so you pretty much have to measure what you have and go from there. If you decide to mill for compression, try to take half off the deck and half off the head. This will leave more thickness to resist warping. A head milled .100" will warp a lot quicker than one milled .050". Also bear in mind that milling .100" will require shorter pushrods since the rocker arm adjusters won't loosen up that much and still have usable geometry. The real key to making power with a slant is to open the exhaust up. You wouldn't believe how restricted a stock manifold is. I didn't until I cut one up. If all you want is a fun driver for cheap, do the milling 50/50 block and deck, go with the 2 barrel Super Six intake and exhaust (larger pipe), with a 198 cam and a stock rebuild with a 3 angle valve job. Then hang on and enjoy the giggles. :shock: BTW slants really like a 3.23 rear gear.
 
A common falicy is that the super six exhaust manifolds have a larger opening. All slant six exhaust manifolds have 1 3/4" outlets.
Milling 0.100" on my 76 head resulted in 39cc chambers and a 9.8:1 compresion ratio (Static compression of 170-175psi). slant pistons are usually .185" down in the cylinders at the top of the stroke.
You do not need shorter push rods after milling 0.100" the adjusters can easily take up the difference.
If I were to do it again I would do as stated above and take 0.050" off of the head and block.
I was able to get a best of 16.35@82 in the 1/4 mile using a 2bbl setup.
the Carter BBD is a very easy to tune carb and a great choice for a slant. you need to look out for worn throttle shaft bushings. I found the v8 BBD to be much more fun than a slant version.
Most gains are to be had by milling for compression, porting the head and adding over sized valves. Remember the slant head was originally designed to flow for 2.8 litres(170ci) not 3.7(225ci), open it up and let it breathe.
 
As for the intake and carb, I would go with a two barrel intake with a two barrel holley...350 cfm. Depending on other factors you may be able to use a 500 cfm two barrel holley. Definetly go to a bigger exhaust. Over on slantsix.org a guy (duster idiot) posted a thread, search "beyond the supersix" where he detailed how he did it. Said it really woke up his engine. I picked up a 7448 holley to do the conversion.
 
Be careful with the bigger 2bbl carbs. Make sure they are staged 2bbls(basicly 1/2 a 4bbl with a primary and a secondary) Without a big cam a 500cfm carb is VERY difficult to tune most people only recomend them for racing. Another problem is that the big 2bbls do not fit the intake without an adapter thus incresing you chances of vacuum leaks and raising the carb and aircleaner into the hoodline.
A carter BBD flows around 280cfm so a 350cfm staged 2bbl is a good step up. I always wanted to try one but I ended up with the clifford 4bbl intake and 465 holley before I could find a good staged 2bbl.
 
Thanks for all the replies.

Got my block and head back yesterday and measured it. The head is 56cc's and I have .170 deck clearance. Crunching the numbers and accounting for a much thicker head gasket. Stock .022 new one .042. with a .010 cut on the head to clean I can take .085 off the block to bring it to 9.45 to 1.

Question? Wht would you take a half and half cut. My thought would be to take more off the block so it is not firing in an open space. Trying to get as much into the head would be benefical considering the head doesn't have a very good quench design.

As far as pushrods I'm not to considered. I have heard that Hemi rods are close. Or i'll cut them down and put new ends on. I haven't picked a cam yet I may go with some ultradyne cam. Exhaustwise, I would like to stick with a stock apparence so haven'e figured that one out yet. Intake, I will use a 2 bbl w/ primary, secondary.
 
I took 0.100" off the head because I didn't pull the engine. I just sent a head out to be milled and a valve job after I ported it, then swapped on the worked head. If I were to do it a gain I would take more off the block than the head. Dont be afraid to take a little more off. I can still run 87 octane at 9.8:1. If I had a steel shim head gasket(getting hard to find) I would be at almost 10:1 (my goal).
 
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