Holley 1850-5
OK, well your talking way over my head. I'm just worried about running on pump gas as it's just a driver. Maybe get a a thicker head gasket to help on that or am I over thinking this?
Did it run on pump gas before any issue?
If so, it will do just fine again.
On talking over your head on the ratio thing .....
Cranking psi rated @ 180 per yourself is a great way to understand what is going on inside the engine on a dynamic level. As the engine spins, it is trapping enough air (&fuel) to create 180 psi which is enough to feed adequately a certain amount of camshaft duration.
On the wish to know what the static compression ratio is, it is a bit hard to determine what it could be because the camshaft is unknown and a cam will change the dynamic ratio up or down depending on the cam size.
Let’s take some numbers that don’t mean anything or add up for a obtuse example.
If you knew the static ratio was 9.5-1...
and camshaft “RRR” is used, you get a reading of 180 psi. This value can change with a different cam. Installing a longer duration cam will lower it.
Install “YYY” cam and the dynamic ratio drops 10 psi to 170 psi. This could be a problem because the “YYY” cam is 10* larger.
The problem becomes a camshaft reducing the psi to a more octane (& wallet) friendly octane level but the draw back is it is now to much camshaft that now feels soggy in power everywhere. It is now inefficient. It’s like giving away HP or allowing your competitor a free shot of NO2.
Just the reverse will happen if you install a smaller cam. The smaller cam “EEE” is 10* smaller than the first. Then the dynamic psi goes up to 190.
This is a problem again because now I take to feed the new high dynamic ratio is ether race fuel @ 3 times the price or impossible to get.
Like I said, these are just numbers thrown out there and 10 psi is and isn’t a lot. It depends on many factors of the engine build and the rear of the car in what it is designed for.
Adding head gasket thickness for a ratio Change In order to drop to a more friendly pump gas level can and normally does add in another issue. Detonation do to poor quench.
I’ve run the Edelbrock head a long time and it works great in the performance arena when you have in the area of a .040 head gasket coupled with a reasonable sized cam. I wouldn’t want to run the piston to head clearance any more than .050 unless it is getting a turbo/super charger.
