434 Camshaft clearance

[flight71]

I thought I had read somewhere that in a stock block you are limited to how much camshaft you can throw at it without hitting the rods even on a small base circle, does anyone know if this is true? What is the limit? Thanks, any info greatly appreciated!

[zipper06]

It kinda depends on the rods you use and what some cam manufacturers call a small base circle. Some cam grinders call a .930 a small base circle and some call a .900 a small base circle. In most cases you're safe with a .630 to .640 lift. I had bullit grind my cam and it's a .870 base circle, i'm running a .689 lift with a set of Lunati Promod rods, but it's also in a Dart lil "M" block, a stock block has the came cam height.

Zip.

[flight71]

I have the eagle h-beam 3D stroker rod with L19 bolts, didnt know of the .870 base circle, thanks for the info!

[ccperf721p]

Duration and separation angle will come into play as well. I've always been fine with .450 lobe lift, but it got a little tight after 278 duration. at 284 / 292 I had to pull .040 from the rods to get what I felt was safe clearance.

Mock it up before the balance work..

[zipper06]

Duration and separation angle will come into play as well. I've always been fine with .450 lobe lift, but it got a little tight after 278 duration. at 284 / 292 I had to pull .040 from the rods to get what I felt was safe clearance.

Mock it up before the balance work..

Yep!
Mine is right in the danger zone, that why i ask them to grind it too an .880 BC which is not standard, but i'd seen the problem before.

Zip.

http://img.photobucket.com/albums/v515/zipper2/bulletcam-1.jpg

[jmarksdragster]

.850 base circle, and ground a little off the Lunati Pro Mod rods on mine. The wider the LSA, the more issues you will have with clearance.

[oldandtired]

The number 2 rod is the clearance problem. Just pull it and run a 7 cylinder!
Dave :D