3RDGENFRANK

On a previous post you recommended the Edelbrock heads for a guy's 350 build-up. What made you choose Edelbrock? The reason I am asking, is I currently have a set of ported Edelbrock RPM heads on my 383. It seems that for a similar price, you can get heads with a more efficient combustion chamber design and bigger runners. So far I am satisfied with the performance of my heads and love the torque. Would a head swap to Trick Flows, AFR's, FastBurns, etc. net a significant gain? I haven't had any other heads on my motor to gauge against. You usually have a pretty good opinion and back it up well so I am curious what you think.

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1992 Camaro Z28; Engine:383 w/Edelbrock RPM ported heads. Lunati Solid Roller Cam 224/232 .502/.502, Fluidampr, 1.5 Roller rockers, 30 lb injectors. Haltech E6GM DFI, SLP 1 3/4" headers, 4" Mufflex, T56, 4.10. Super Ram.

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Definition:

NOPI: n. 1. import 2. Sticker worth 47 hp 3. import with 6" exhaust tip
antonym: smallblock

The ODB

Well the Edlebrocks are not the best or worse, but a very good performing true bolt on head. I couldn't see a performance difference justifying the price of replacing the heads, especially in a street application. The street heads are all so close that I'd go to a different angle before I'd swap on another 23* set.

The only thing I see questionable about your setup is that you're not taking full advantage of Edlebrocks casting design with the valve lift you are using. I would definately run a higher ratio rocker, and probably advance the cam just to see how the engine responded to that.
I'm basing my opinion of the valve lift on some research done by David Vizard, and not on what Edlebrock recommends.
The other thing is that I would run no less than 11:1 compression with those heads & cam.
well there's my feelings.
People I know make pretty big hp numbers with those heads on low-buck engines.
ODB

3RDGENFRANK

Thanks, ODB. I got a great deal on the longblock I have so I had to make a few compromises. Budget allowing, I will soon replace the 1.5's with 1.6's. That will take me to .535" lift. Also, my motor has a mind-boggling 9.3 to 1 CR. Eventually I will upgrade to 6" rods and at least 10.5 to 1 compression. That should wake my motor up very nicely.

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1992 Camaro Z28; Engine:383 w/Edelbrock RPM ported heads. Lunati Solid Roller Cam 224/232 .502/.502, Fluidampr, 1.5 Roller rockers, 30 lb injectors. Haltech E6GM DFI, SLP 1 3/4" headers, 4" Mufflex, T56, 4.10. Super Ram.

Double-Pump This! EFI Rules!

Definition:

NOPI: n. 1. import 2. Sticker worth 47 hp 3. import with 6" exhaust tip
antonym: smallblock

Matt98SS

why bother upgrading to 6" rods? There is not power to be gained there. Just less $ in the pockets. Spend that $ towards some porting of the heads

3RDGENFRANK

Matt, going to six inch rods will increase the time that the piston stays at TDC. This helps to increase the tolerance for a compression ratio increase and still be able to use regular gas. Also, it puts less load on the cylinder walls to decrease friction. The piston rod angle also changes less through each revolution which will help durability. Plus, my heads are already pretty extensively ported. I'm just trying to decide whether to go to a Miniram or not. I may try building my own intake. I'm still trying to figure out plenum volume/runner length and engine dynamics interactions. I may just have to experiment.

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1992 Camaro Z28; Engine:383 w/Edelbrock RPM ported heads. Lunati Solid Roller Cam 224/232 .502/.502, Fluidampr, 1.5 Roller rockers, 30 lb injectors. Haltech E6GM DFI, SLP 1 3/4" headers, 4" Mufflex, T56, 4.10. Super Ram.

Double-Pump This! EFI Rules!

Definition:

NOPI: n. 1. import 2. Sticker worth 47 hp 3. import with 6" exhaust tip
antonym: smallblock

The ODB

If this helps your budget any...

I run the stock 5.7" rods in my 383 @ 11:1 compression and do fine on pump gas.

I think the chamber shape and amount of quench area has a bigger effect on detonation resistance than dwell time at TDC does. There are also many cheaper ways to avoid detonation, like running colder plugs.

FYI

FlashGTA

Another way to decrease the chance of detonation is to polish the combustion chamber and chamfer any sharp edges on the piston and the combustion chamber. Also the more efficient a combustion chamber is the less spark advance it needs which again means less chance of detonation.