496 MAG Cams

[Beer-30]

Understandable, Ray. I know you know more than probably anyone else here about this motor........but.
You have got to be kidding me that there is only .010 right now between my valves and the pistons. HO lift at the valve is .510, and you are telling me that with a little extra heat (expansion) and a quick out of water over-rev, the pistons are gonna hit? C'mon. GM has never put out a motor with that tight of clearances, even back when they had .600 lift cams in the '70s.
I am sold on your kit, ok? There are just some of us that don't mind tinkering a little until we get there. We have been through this before. If you want us to use your rockers instead of Comp Cams or another, fine.
For the other comment about stock covers, besides the slightly different bolt pattern, there is the stock coils to be mounted. I know that Eddie and I think Rex (at least) are working on new covers with a coil bracket for under the exhaust.
Ray, I know there are spacers made, and maybe they are mandatory, but I have a hard time believing that GM has changed the spacing between the valves/rockers and covers from previous big blocks. I know of at least two 454s that are running either Stainless, like yours (or whoever's you use) and Aluminum under stock covers. The alum are not 1.8s, but I know the Stainless ones are. I have see the 1.8 motor with the stock covers on, and running. Is it really that different from a standard Gen V-VI head?
Additionally, you are saying you have moved the valve up and away from the pistons for you to be able to run 1.8 rockers or your larger cams, but the valves are still not hitting the valve covers? I don't get it! Did you space the valves away from the pistons? or the covers? I don't see how it could be both, unless you layed them sideways????

[Raylar]

The problem with going above .520 lift on stock 496's is not just the clearances, its the fact that the stock springs are weakies. They have just 90lbs on the seat and about 260lbs open pressure. The stock big heavy valves have a tendency to start the lifters into pump up around 4900 to 5000 rpms and if you have any more than .520 lift on stock springs no matter how you get it, cam or rocker ratio you can start to see valve float and lifter pump up (solid lifter) and you will probably have an intake valve kiss a hypereutectic piston, bend over its gone! The stock 496 valve covers are 3/4" approx. shorter (lower) than the gen 6 covers and hence there's less clearance for roller rockers and the poly lock adjustment nuts needed to adjust the rockers. The rocker studs in 496's have a metric adjustment nut and thread and after market kits come with SAE threads, won't work. Wan't to know how we did it, buy our cylinder heads and rockers and you will know.
Everybody loves to tinker and try and make improvements, just be careful you check your tinkering carefully before you put the hammer down! If you have a problem, call us we have complete motors ready to go.
We also have our stainless coil remount brackets in stock that mount the coils under the exhaust manifolds. And our new valve covers with polished stainless tops should be ready shortly. More "Bling" for the 496!
Good Luck with the tinkering!
Ray @ Raylar

[Beer-30]

Thanks again, Ray.

[Raylar]

You guys are all very welcome! :wink: Hope I can always help fellow boaters. These forums can be great for everyone!
Regards
Ray @ Raylar

[franky]

Ray, do you have flow bench data for your heads vs. stock mercs?

[franky]

Or you can mount the coils behind the heads, out of the way like these:
http://www2.***boat.com/image_center...22PDRM0728.JPG
http://www2.***boat.com/image_center...22PDRM0729.JPG

[Beer-30]

Nice. Good job, Franky.

[Raylar]

Franky;
The flow bench data on our heads is on our website, go to the cylinder head page and click on flow data. Not to say it hasn't improved since this pro-type data was done 1-1/2 ago. We like to keep the real numbers close to the vest.
Ray @ Raylar

[franky]

I have real numbers if you want to see them.

[Beer-30]

I have real numbers if you want to see them.
Hey Franky. Do you have numbers from an ASM intake? Curious how it compared. I saw you were putting a motor together with said intake. Was it on Raylar heads? Stock? Can you spill info?