- Local time
- 5:17 AM
- Joined
- Apr 13, 2012
- Messages
- 35,615
- Reaction score
- 125,497
- Location
- Granite Bay CA
Hello, first time in the racers forum. Hope that someone can offer a few suggestions.
I've posted numerous times in the other forums here about the detonation issues I've had with the 440/493 in my Charger. I think I've found a fix, but I still have a few questions.
The engine is a .030 over 440 with a 4.15 crank. Pistons are flat tops, .017 in the hole, currently have a .039 head gasket. 84 cc Edelbrock performer RPM heads UNported. The compression ratio specs out at 10.73 to one. MP '509 cam installed straight up, between 185-193 cranking compression.
The quench distance is at .056 and many here have agreed that as it is, I don't have much quench happening at that range. I want to switch to a bigger cam and think I have found one that should help, as its intake closing is later that my '509 by at least 4 degrees. The Comp Cam XE294H will have 250/256 degrees of duration @ .050 with .553/.558 lift using my 1.6 rocker arms . 110 LSA.
The question here is the head gaskets. Several sources for a .051 exist. I'd run a .060 Cometic but at nearly $300 a pair, that is pretty steep. The .051 gaskets have different bore sizes. The smallest I've seen is a 4.410 like the common Fel Pro ones I have now. I've seen other .051 gaskets with a 4.590 bore size. I punched the two bore sizes into a compression calculator and found this:
With .039 gasket: 10.73 compression
With .051 gasket, 4.410 bore, 10.45 compression
With .051 gasket, 4.590 bore, 10.36 compression.
Using a standard 440 block and the Edelbrock heads, is it a problem to use the gasket with the larger bore size?
Thanks, Greg
I've posted numerous times in the other forums here about the detonation issues I've had with the 440/493 in my Charger. I think I've found a fix, but I still have a few questions.
The engine is a .030 over 440 with a 4.15 crank. Pistons are flat tops, .017 in the hole, currently have a .039 head gasket. 84 cc Edelbrock performer RPM heads UNported. The compression ratio specs out at 10.73 to one. MP '509 cam installed straight up, between 185-193 cranking compression.
The quench distance is at .056 and many here have agreed that as it is, I don't have much quench happening at that range. I want to switch to a bigger cam and think I have found one that should help, as its intake closing is later that my '509 by at least 4 degrees. The Comp Cam XE294H will have 250/256 degrees of duration @ .050 with .553/.558 lift using my 1.6 rocker arms . 110 LSA.
The question here is the head gaskets. Several sources for a .051 exist. I'd run a .060 Cometic but at nearly $300 a pair, that is pretty steep. The .051 gaskets have different bore sizes. The smallest I've seen is a 4.410 like the common Fel Pro ones I have now. I've seen other .051 gaskets with a 4.590 bore size. I punched the two bore sizes into a compression calculator and found this:
With .039 gasket: 10.73 compression
With .051 gasket, 4.410 bore, 10.45 compression
With .051 gasket, 4.590 bore, 10.36 compression.
Using a standard 440 block and the Edelbrock heads, is it a problem to use the gasket with the larger bore size?
Thanks, Greg