Choosing pistons and camshaft for 360 street build (economy + fun)

[vntned]

miscalculation

 

[RustyRatRod]

Stock open chamber heads are in the 73cc range. Uncut, with a regular headgasket, the tend to measure in the 9.5:1 range. With the piston barely below deck, the valve reliefs in the piston and the large chamber, they don’t break 10:1 without milling, nailhead valves, thin headgaskets, etc.. Calculated compression vs actual tend to be very different.

And even if it does hit 10:1cr, there’s nothing wrong with that in a streetcar running good gas.

They are far from all the same. I've seen them as small as 67cc. I'm not arguing the point. I'm telling you what we ended up with. Go for it. Build it at 12:1. It's not mine. My car runs great.

 

[RustyRatRod]

miscalculation

Yes. On your part.

 

[vntned]

Yes. On your part.

Good one! Got me there! Real zinger!

 

[crackedback]

at 8000 elevation a high compression ratio is not going to be an issue.

Driving a high altitude build at sea level, might be a challenge!

 

[mbaird]

8600 ft ? Where are you ?
There are a few Colorado towns up that high but most are real tiny and snowed in all but a few months .
Do you mean 860’ ?

 

[SpeedThrills]

8600 ft ? Where are you ?
There are a few Colorado towns up that high but most are real tiny and snowed in all but a few months .
Do you mean 860’ ?

See post #17.

 

[mbaird]

See post #17.

Missed that …But which town ? Just curious… will be camping in Colorado for 10 days in a few weeks .
If you have residence in both CO and Florida be careful about high Compression. Besides super high compression street cars are harder to sell . Kinda limits the market to the other 100 people that live at that elevation . Lol

 

[273]

It's still gonna have a similar relative gain, your just starting slower stock and end up slower modified than an engine at lower elevations but the gain from stock to modified should be similar.

 

[PROSTOCKTOM]

Either way the towns in Colorado that are at 8600', or above are all either near Denver, Colorado Springs, or in between.

Which most likely you'll be driving in one, or both cities, so this engine needs more compression than what would be required at my 572' elevation here in Indiana.

Good luck with the project

Tom

 

[Dart Frog]

What do you believe to be the cause of this?

Too many small variables that can all add up.

 

[92b]

Too many small variables that can all add up.

I see it alot at the dyno. That's why I bought a whistle.

 

[VintageRocker]

Thank you all, busy days moving into my new home. But I'm reading everything. I didn't know that a post with the "high altitude variable" could be that interesting. The car is being worked on in Miami, I'm buying the new parts little by little and now I'm thinking about Silv-o-lite 1279HC + Comp XE256/262H... And I just realized that I'll need a new radiator

 

[ValiantKevin]

I am in Bailey CO, around 8k feet elevation... my stock 170 /6 hates it here lol

 

[340six]

Repetitive Flood Loss Area Analysis | Kenner, LA.

The part of city I live in is below sea level.
The street is about 8 feet below. According to engineers that did my elevation certificate.
We have elaborate drainage and pump systems. And levy. We pump it all out.
So can I run 12 to 1?

 

[Dart Frog]

Repetitive Flood Loss Area Analysis | Kenner, LA.

The part of city I live in is below sea level.
The street is about 8 feet below. According to engineers that did my elevation certificate.
We have elaborate drainage and pump systems. And levy. We pump it all out.
So can I run 12 to 1?

Oh yeah 12 to 1 13 to 1. 36° timing and iron heads! On pump gas ..this is the internet you can do anything I see it all the time

 

[ValiantKevin]

Repetitive Flood Loss Area Analysis | Kenner, LA.

The part of city I live in is below sea level.
The street is about 8 feet below. According to engineers that did my elevation certificate.
We have elaborate drainage and pump systems. And levy. We pump it all out.
So can I run 12 to 1?

I mean for a little bit sure lol

 

[340six]

Oh yeah 12 to 1 13 to 1. 36° timing and iron heads! On pump gas ..this is the internet you can do anything I see it all the time

I saw an advertisement for a automobile battery.
Said something like battery less than 6 months old. 750CCA used less than 50 starts. So 700 starts left.

 

[Dart Frog]

I saw an advertisement for a automobile battery.
Said something like battery less than 6 months old. 750CCA used less than 50 starts. So 700 starts left.

Well yeah, 750 car cranks available