Hi Harold, (not Sutton :)
I searched the forum for roller cam recommendations for a 496, but came up empty. so as long as I'm going through this endeavor, I figure I might as well ask the expert.
The engine has AFR 305 CNC chamber heads.
Carb will be a 1050 Dominator, Victor 454R intake.
CR is 9.5:1
The only street driving the car will see is too and from the dragstrip....well, hopefully always "from".
So I don't care about street manners.
I'd like to see max hp around 6500.
We are thinking something in the 260/270 range, and around .680 net lift.
Suggestions?
Thanks.
Ron

Here's a couple of posts about the 502A4LUN

http://www.chevelles.com/cgi-bin/forum/ultimatebb.cgi/topic/4/19170.html?


http://www.chevelles.com/forum/ultimatebb.php?ubb=get_topic;f=4;t=020305

Thanks Kboorman,
Those numbers are nearly the same as the Comp XR292R-10, that I already have. But good info just the same.
We are looking to possibly go bigger.
Ron

"bump"

I talked to Tony @ AFR and he told me that I should go with a solid roller .252/.258 @.050 with about .714 lift. I'm still kind of Iffy on this! He also wants me to go with at least 10:5 to 1 compression. I told him I wanted a reliable street engine and he said he could give it to me with these specs, I would have to trust him! What do you think? He said that the custom grind cam he will spec out for me will be a billet core and even though he uses over .700 lift the cam will require .020-.025 valve lash, and after that loss and some valvetrain deflection I would only actually be seeing somewhere around .675 net....that puts my valves spending LOTS of time between .550 and .650.... perfect for the 305 head to shine. He also said I should trust the MASTER!!!!!!!!!!!Funny Guy! Should I go with his specs or not, need replys.

Tough to beat the opinion of the man who designed the heads! If you want the best out of these heads, you should take advantage of their flow characteristics, especially at high lift.

Only thing I would add is make sure the valvetrain is up to it: shaft rockers or good stud mounted rockers with a stud girdle, and don't forget to use good stiff pushrods to help keep deflection and harmonics to a minimum. When I oprdered my pushrods from Manton, I had a chance to talk to Terry Manton about pushrod stiffness and weight. I had decided On 7/16" 0.08 wall, but when he told me that they were available in .120 wall, I didn't need much convincing to go with them.

A great guy to talk to, and deal with.

John

Ron, I'm watching for Harold to post here too. I'm still on the fence as far as cam selection for a similar motor (with a bit more CR). Here's a post where Harold talks about some bigger cams:
http://www.chevelles.com/cgi-bin/forum/ultimatebb.cgi?ubb=get_topic;f=4;t=020018;p=1

I'm also curious to see how big a cam is recommended with your 9.5 CR.

Well,
We spoke to Comp and decided to go with a custom Extreme energy solid roller on a billet core. Specs will be 260/266 with right at 680 net valve lift. 110 lobe sep. Not a huge step up from the XR292R-10, right at 6 degrees more. Again, I will be able to exchange the Comp cam I already bought...before I joined this group.
I have also decided to try the Comp polymer distributor gear. At least it won't be metal.....if for some reason it fails.
So I guess the dyno test will be a month or more in the future.
396-375.....I think you have been advised correctly. If you are squeamish, you could go a bit smaller, and not leave too much on the table. Me, I wan all I can get from this combo....I have people to beat. :) And they can keep their bottles..........
Ron

If it will only be driven to and from the track, why have 9.5:1? You can have 11.0:1 with that engine and run it on premium, and make probably 40 more hp. Also, from what I've seen, cams over 250ish at 0.050 start to give up low end with low compression.

DF

Hi Dave,
I agree with your assesment. The "plan" was to have 10.5, and I bought the parts that were supposed to get there.
Well, the pistons ended up between 0 and +.007 above the deck due to the fact the deck had been cut once. So my engine guy decided we needed to go to .051" head gaskets. He just wasn't comfortable with .032" piston to head clearance with the 4.25" stroke.
Then we decided to bevel the edges of the chamber to help unshroud the valves a bit. And, the AFR heads are 121cc instead of the 119 I thought they were.
SRP pistons come in 2 varieties off the shelf for the 4.32" bore. The ones I used are were suposed to be 10.2:1, and the next available goes way up to over 12:1.
So we got what we got, and will have to live with it. Seems like unless you go custom pistons, there just aren't any "tweeners" off the shelf.
Besides....this leaves room for a Procharger.....

BTW....this is a 10" tire car, and any loss in low end will only help traction. We don't get the best track prep on a weekly basis.

You are doing a good job with HRM.....keep up the good work. I've been a reader since I can remember. And I'm approaching the big 5-0
Ron

HOPING UDHAROLD WILL POST HERE!!!!!!NEED HELP :eek:

Call UDHarold at Lunati and have him set you up with one of his Ultradyne hyd rollers.
Somewhere around 247-251 @.050 .650 lift single pattern on a 110 sep.

Just make sure the converter matches and you`ll be set to go.