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Discussion Starter #21
So woth 11.9comp ratio its recomending 106? Dam thats higher then i would have hoped. Does it correct for dynamic compression or just static?
 

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Thanka for the info. I will send bill miller and email.

I have tried to guess at the heads but really i think the bottom end needs to be built first then i can pick the heads out.

I am looking at the best pricing option that will get me around where the flow looks like it needs to be. Maybe ported eq heads or something that can be milled down enough. The only small chamber heads i could find were darts that come 49cc in an angle plug.

I have emailed some head porters from this forum and just waiting to hear back.

Ya it does i wouldnt have guessed those numbers.

I was getting my headflow recomendation from the calculators on wallace racing websight and figures about 255cfm up to 315(for max output 127.5%ve)And i just picked an off the shelf cam that i could find online and did the math for dynamic compression to allow me to run pump gas.

I imagen that pipemax programme is picking the optimal compression thats why the numbers are high and the recomended octane is 106?
The 49 cc stuff is decent, but it’s flat milled, and there’s only about 50 Thousands left to angle mill. We got a set on that 303” they’re good, but if I had to do it over, I’d go with a 64 cc and angle mill them. Now, RHS makes a 49 cc 215 intake runner that is angle milled to 21 degree. But, they quit making them, but they can still be found. It’s a raised runner head. Good head. AFR has some great choices also. Brodix and Dart do too. I’d go with aluminum if that ain’t a problem. Don’t go huge on the runner size. You won’t like it.
 

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So woth 11.9comp ratio its recomending 106? Dam thats higher then i would have hoped. Does it correct for dynamic compression or just static?
Static Compression Ratio = 11.964
Intake Valve Lash = 0.016

Cranking PSI = 183.7 psi ( at 150 RPM engine starter cranking speed )
as Low as 146.1 psi with aluminum block or with poor ring seal

Note=> after 7 to 10 needle pulses on a hi-quality Compression Tester
the slower the cranking RPM, the lesser the cranking psi
the faster the cranking RPM, the greater the cranking psi
the poorer the Piston Ring seal, the lesser the cranking psi
in addition, aluminum Blocks may show lesser cranking psi
Also Engine should be between 140 F to 180 F temperature for Tests

The Tester's Needle should swing over to 90+ or more psi on the 1st Pulse
this indicates great Hone Job, Valve Guides, and Valve Job

Dynamic Compression Ratio (DCR) = 9.552:1 Clearance Volume CC's = 54.5
Dynamic Effective Stroke = 2.3399 inches with Cylinder Volume CC's = 466.3
Dynamic Valve Lash Compression Ratio = 8.798:1 at Starter Cranking RPM

I'm not sure why it calls for 106, my copy of pipemax is very old.
 

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Discussion Starter #26
I will have some more looking to do for heads for sure. Like i said i have emailed some porters about what they could do and will have to see the price. I would love a set of 200cc pro 1s with 49cc chambers but i cant afford that right now. But might be able to afford a bare set of ported irons i will just have to wait and see.

I do have a set of pre eliminator afr 195s that i could get milled locally but i dont want to rip apart my blower motor to build this one.
 

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You’ll be fine. And again, if running a 23 degree head, run the long rod. 8,500 rpm in that thing won’t be a problem. And the good stud mount rockers will handle that fine. You won’t need over 240#’s on the seat for pressure, and rockers made today handle that fine. Run 7/16 studs, and a girdle. Run lash caps.
you may wish to revise spring pressure recommendations he wants a solid F/T cam
 

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Had a buddy (now deceased) who built 307's instead of 283's in the 70's. He said he like the extra torque and it would still spin to 7500 with the old shitty heads from back then. They were all 12 to 1 engines and with today's heads, cams and intakes might be a real HP screamer today.
 

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Had a buddy (now deceased) who built 307's instead of 283's in the 70's. He said he like the extra torque and it would still spin to 7500 with the old shitty heads from back then. They were all 12 to 1 engines and with today's heads, cams and intakes might be a real HP screamer today.
Oh, they would be. Night and day difference today.
 

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So my Camaro's original 307 that I have sitting in the corner of my garage might not be completely useless after all.
I just took a 307 out of my son-in-law’s car, and replaced it with a 307, 60 over, with flattop 0.043, 0.043, 3 mm, 2 valve relief pistons, and his original block looks real straight, so we will keep it.
 

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Discussion Starter #40
ya i know a 350 is a much cheaper and easier motor to build, but this is a 67 283 that came factory in my el camino, always wanted the factory motor back in the car.
 
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