Well behaved cam for small block 406
Last edited by HeadsU.P.; Jun 22, 2018 at 06:46 PM.





Your compression ratio determines the max duration before the DCR makes the engine lazy. Since you know how it runs with a 224/234 You could jump up 4-6 degrees on the intake. How restrictive the exhaust is determines the exhaust split duration. Headers and true duals might only need a split of 4-8 degrees
Last edited by gkull; Jun 22, 2018 at 07:30 PM.
Your compression ratio determines the max duration before the DCR makes the engine lazy. Since you know how it runs with a 224/234 You could jump up 4-6 degrees on the intake. How restrictive the exhaust is determines the exhaust split duration. Headers and true duals might only need a split of 4-8 degrees
I was considering something like a 228/232 114 with lift in the .480 range, but couldn't find any shelf cam with those specs. Closest I came was a 230 squared cam with a 114lsa. Don't have a clue how to figure DCR in a Gen 1 engine with hyd flat tappet cam. I usually shoot for 8.0:1 in an LS3 with a blower and 8.2+ n/a. It's common to use ground in advance in addition to duration and LSA to fine tune DCR in cams for LS motors. Haven't seen advance even mentioned in the Gen 1 cams.
I was considering something like a 228/232 114 with lift in the .480 range, but couldn't find any shelf cam with those specs. Closest I came was a 230 squared cam with a 114lsa. Don't have a clue how to figure DCR in a Gen 1 engine with hyd flat tappet cam. I usually shoot for 8.0:1 in an LS3 with a blower and 8.2+ n/a. It's common to use ground in advance in addition to duration and LSA to fine tune DCR in cams for LS motors. Haven't seen advance even mentioned in the Gen 1 cams.
I had a 406" Pontiac, 10.0-1, Ported Ram Air III heads (flowed around 230 cfm at .500"), Torker II single plane.... I used an Ultradyne cam that was spec'd by UDHarold himself. It was a 288/296, 231/239*,.485/.507", 110 LSA. That setup was a budget build, but it in a 3650lb Trans Am ran 12.00s@109 mph...with a way too loose 2800 converter, 3.42 gears and a 26" slick. The engine ran great, had good vacuum, idled clean, never fouled plugs, it was just a great running combo.... It was actually my daily driver in high school at that time. I ran that cam for years, before I eventually went to a solid flat tappet that was much bigger and slowed the car down..
I understand we are talking about totally different engine platforms here but.... The basics are similar, and I think I'd be looking at something in that range, based off of my experience with it. To this day, I've yet to have a mild/budget style engine run THAT good again...I'm certain the cam was the key. I know they made ALMOST that exact same cam for SBCs back then, just different lift.
I know this is not the correct way to recommend a cam for a combo, but I'm just giving you some feedback on what I found with a cam in the size range that I think you'll end up.
The Best of Corvette for Corvette Enthusiasts
Hydraulic flat tappet profiles:
The intake lobe is the H5. 288*, 231*@.050", .485" w/1.5 rocker
The exhaust lobe is the H15, 296*, 239*@.050", .507" w/1.5 rocker
This is for SBC and Pontiac...and is the same for Bullet and Ultradyne. I guess Bullet just took over Ultradyne's catalog after Harold passed away.
Definitely worth looking into if you want to do something a little unique.
www.ultradyne.com





I would look into the Extreme h flat lobe profiles. Just pick out the lobe with the duration that you want and tell them the valve event numbers. You just have to look up cam card valve event numbers of some of their existing off the shelf cams. Years ago I figured out that comp cams extreme series of cams was ground 4 degrees advanced compared to say Crane cams of equal duration. You need to read up on advancing or retarding cam timing. I have my custom cams ground 4 degrees retarded and install them straight up so I'm not playing with the timing set keyways unless the degree wheel said that I need to alter a slightly wrongly ground cam
I only have cams made from billet steel and sleeved on dizzy gear. Never have to worry about the cam going flat on break in even with the extreme pressures of roller springs
then I figured out how to buy springs from CC spring chart pdf catalog
that way I'm not at the mercy of some high school drop outs working for something not much above minimum wage who have been given the title of tech support and only know what is in the company manual canned answers
Hydraulic flat tappet profiles:
The intake lobe is the H5. 288*, 231*@.050", .485" w/1.5 rocker
The exhaust lobe is the H15, 296*, 239*@.050", .507" w/1.5 rocker
This is for SBC and Pontiac...and is the same for Bullet and Ultradyne. I guess Bullet just took over Ultradyne's catalog after Harold passed away.
Definitely worth looking into if you want to do something a little unique.
www.ultradyne.com
Last edited by old motorhead; Jun 23, 2018 at 09:34 AM.
I would look into the Extreme h flat lobe profiles. Just pick out the lobe with the duration that you want and tell them the valve event numbers. You just have to look up cam card valve event numbers of some of their existing off the shelf cams. Years ago I figured out that comp cams extreme series of cams was ground 4 degrees advanced compared to say Crane cams of equal duration. You need to read up on advancing or retarding cam timing. I have my custom cams ground 4 degrees retarded and install them straight up so I'm not playing with the timing set keyways unless the degree wheel said that I need to alter a slightly wrongly ground cam
I only have cams made from billet steel and sleeved on dizzy gear. Never have to worry about the cam going flat on break in even with the extreme pressures of roller springs
then I figured out how to buy springs from CC spring chart pdf catalog
that way I'm not at the mercy of some high school drop outs working for something not much above minimum wage who have been given the title of tech support and only know what is in the company manual canned answers





Hydraulic flat tappet profiles:
The intake lobe is the H5. 288*, 231*@.050", .485" w/1.5 rocker
The exhaust lobe is the H15, 296*, 239*@.050", .507" w/1.5 rocker
This is for SBC and Pontiac...and is the same for Bullet and Ultradyne. I guess Bullet just took over Ultradyne's catalog after Harold passed away.
Definitely worth looking into if you want to do something a little unique.
www.ultradyne.com








