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Discussion Starter · #1 ·
I am building a 68 327 think it is a 210hp. Has dish pistons with 2 valve reliefs, read it is 8.75 to 1 compression. what heads were used to on this engine are they 70cc heads or 64cc? I have other pistons but could never find info on what heads it had from the factory.
 

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My 327 is a couple yrs older than yours. It has flat top 4 valve relief pistons and Power Pack heads like the 4bbl 283s had. 58 or 60 cc chambers,I think. 70 cc sounds way to big for the shorter stroke of a 327, especially with dished pistons.
 

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Discussion Starter · #4 ·
I appreciate the help. The dish pistons are history and have a set of 100 dome on powdered rods going in with ported 461 heads weiand t ram with twin 600s. So 10.5 to 11.0 to 1 one with a mutha thumper cam should be enough to make up for excessive overlap and help it run the way it should. I know there are other cams out there that make better power and I have a few if I dont like this one.
 

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I personally like the Thumpr series cams. They get a lot of bad feedback from those who haven't used them and call them "poser cams", but they really aren't just a "sound" cam. I've installed a few of them, and everyone who owns one loves them. I have the Mutha Thumpr in my BBC, and it's wicked sounding, and really performs. In a SBC that's not high compression, I'd recommend the lower level Thumpr myself, as the entry or mid level Thumpr seem to do well with lower compression. Even the mid range requires a 9.5:1 compression. The bigger Thumpr needs a stick, or an automatic with a lot of stall in the converter, as they have such short LSA and lots of overlap.
You'll also find that if you do much idling, or starting and stopping, the Mutha Thumpr will add to spark plug fouling. Need to get it out and burn the plugs clean once in awhile, and eventually they just wont clean out. I replace plugs about every 6 months in my BBC from short starts to move it, or traffic that wont let me clean it out.
 

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Discussion Starter · #6 ·
Cool, this is the first of comps thumpers that I plan to use. I am using the mutha thumper and figure the higher compression will help with overlap, they are not much different than a cirlce track cam. I have a 3000 stall and I am working on getting a ford 9 inch. My friend has a set of gears prob a little too low for it. They are out of a dirt track combo think they are in the area of 5.80s. Would like to maybe go as low as a 5.13 but may stay in the 4.11 to 4.56 range. Have a weiand t-ram I might use if anyone on here knows whether I will need to cut the hood to run in a 52 chevy sedan. If I do I may run an RPM with a modified 390dp or a 600 eddy carb on it. The hoods are out there but but getting harder to find and alot harder explaining the need for it when the credit card bill comes in.
 

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Discussion Starter · #7 ·
The dish pistons came out in farm and HD trucks in 68. Mine has a 4672 casting steel crank as well. I have 100 domes I am running with it but need to have the crank checked to make sure it isnt needing balanced with this setup.
 

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Good idea on balancing the rotating assembly. It's not a huge expense and you'll really feel a huge difference in smoothness with a well balanced motor!
 

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Discussion Starter · #9 ·
Began assembling the short block tonite. I have ARPs 134-5001 main bolts and they are too long for the block. I read an article that said that on some 68 blocks they used the small journal main bolts with the large journal caps. Is this accurate? I could put a couple more washers under it if that tells you the extra length I am dealing with. Just wanting to see if I should use the small journal bolts
 

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Haven't dealt with many of that gen 327, and I used stock main bolts on mine, so didn't run into this. I'd contact ARP and ask about using washers, and whether it is good or bad.
 
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