High compression

[Max1329]

What’s the highest compression that a stock 5.7 bottom end can handle?

 

[HemiLonestar]

Trying to bolt on eagle heads without thicker gaskets?

 

[Max1329]

Trying to bolt on eagle heads without thicker gaskets?

Well 6.1 heads but yeah

 

[Fast69Mopar]

Well 6.1 heads but yeah

6.1 heads on a 5.7 with a stock-thickness gasket isn't a huge jump in compression like the Eagle head is. I have a pair of 6.1 heads in top of my daily driver right now with a stock gasket. My compression ratio comes out to 10.71:1 which with decent tuning will be fine. I can get away with cheap gas in a pinch as long as I don't drive it hard. I mainly run 89 octane on the street with 36° of timing and no KR (Knock Retard). When I run 87 octane I will see 2-3° of KR when the engine and cylinder head temps get hot from running it hard. With 93 octane in the tank I can run 38° of timing with no KR.

 

[HemiLonestar]

What cam? Cam selection and tune are important here. Regardless, you generally don't wanna exceed 11:1 on the stock 5.7 components.

 

[Max1329]

What cam? Cam selection and tune are important here. Regardless, you generally don't wanna exceed 11:1 on the stock 5.7 components.

Comp hrt stage 3

 

[MAC830203]

That’s a different question. How much compression can a short block withstand?
Any block can take gobs of Comp. the real question is how much RPM and HP can a short block withstand at zero deck, forged slugs, H rods and a forged crank? About 600hp at 6000 rpm. After that, it’s frequency, wall thickness, bearings, etc. Cap Walk will raise its head there too.
An engine with high comp can have a longer duration cam. 87 octane is ok up to 9.9-10 with 20*+ advance. Anything over 10.7 with torque management removed needs 93+ octane. 11:1 and it will knock and risk piston detonation. You pose a different question that would be interesting to figure out. Some engine builders use flat pistons to get up to 15:1. Quench and clearance matter. Over .045 of deck clearance will produce knock. Under.038 and you’ll get a super quench engine or smack the pistons on the head when hot and you get into it. I’ve had issues with head gaskets when I had a block zero decked. So I go with .040 clearance. Aa gasket close to the size of the bore as possible and in the hole at .012. I find less heat directly to the gasket. In short, use the head gasket that gets you to .040 compressed between the piston at TDC and Cyl head.

 

[Max1329]

That’s a different question. How much compression can a short block withstand?
Any block can take gobs of Comp. the real question is how much RPM and HP can a short block withstand at zero deck, forged slugs, H rods and a forged crank? About 600hp at 6000 rpm. After that, it’s frequency, wall thickness, bearings, etc. Cap Walk will raise its head there too.
An engine with high comp can have a longer duration cam. 87 octane is ok up to 9.9-10 with 20*+ advance. Anything over 10.7 with torque management removed needs 93+ octane. 11:1 and it will knock and risk piston detonation. You pose a different question that would be interesting to figure out. Some engine builders use flat pistons to get up to 15:1. Quench and clearance matter. Over .045 of deck clearance will produce knock. Under.038 and you’ll get a super quench engine or smack the pistons on the head when hot and you get into it. I’ve had issues with head gaskets when I had a block zero decked. So I go with .040 clearance. Aa gasket close to the size of the bore as possible and in the hole at .012. I find less heat directly to the gasket. In short, use the head gasket that gets you to .040 compressed between the piston at TDC and Cyl head.

Sorry but I’m not referring to a forged crank of any of that as I said I’m referring to bone stock lower end no decking or piston changes as stated in original post