With all the 8.1 talk lately thought i would keep it going and share a vid from when i put my truck back together Cammed 8.1 Avalanche - YouTube enjoy

 

maker and specs on cam, valve springs, valvetrain mods more info please.

Sounds really nice hows it run.

 

Cam is a factory mercruiser 496ho cam. Spec s I believe somewhere around 226/233 on a 114 lsa....don't quote me on that. Had the cam laying around so I slapped it in. It is not really ideal in a truck this heavy....has great midrange but low end is lacking. Still will spin 35 ' s from a dead stop. The heads are factory heads milled .040" 2.25" intake valves 1.80" exhaust stainless ferra valves with 11/32 stems, bronze guides, ported and cleaned up bowls. Can't remember the spring specs think they are 120lbs on the seat. Titanium retainers, hard and sharp 1.8 rocker arms, comp hardened pushrods. Arp head studs, cosmetic head gaskets. Factory intake....going to cut it up soon and port it because it's a major bottle neck. 1 7/8" Stainless works long tube no cats x pipe sweet thunder mufflers. Made 350 hp 400tq with 35 ' s and running in 2nd gear on a dyno jet

 

Meant to say Mustang dyno not dyno jet

 

Sounds badass man, the h2's look sweet as well

 

Neat stuff! Always happy to see a built 8.1L.

 

Hell ya such a small market for these things. Future plans include some of your aluminum heads, stroker possibly and a blower. I may swap cams with one of yours in the meantime to play around....I don't think this ho cam is optimal nor is the stock intake helping. I have another intake I am going to chop up as well as some 42lb marine injectors because the stock ones are pretty close to maxed out

 

If you like the 496HO cam in your 8.1, you'll probably really like the BP-203. It was originally developed as a performance oriented replacement for the 496HO camshaft. Better torque and more horsepower while still retaining stock like driveability. The BP-203 is as big as you can run from us on the stock heads and stock pistons.

If you're switching to the aluminum heads and notched pistons, then you can go nuts and run either the BP-205 (same duration as the BP-203 with .600+ lift) or our more aggressive BP-206 camshaft which makes 600+hp/630+trq. Or if you really want to go nuts there's the BP-213 camshaft, but you'll want a good aftermarket stall for that one.

The stock intake manifolds are awful and were built with cost as the number one priority. They neck down just after the throttle body to roughly a 55mm opening. As you might imagine, it completely starves the engine for air past 4k. The ported stock manifold still retains stock looks and flows enough air to make good power. The problem with the stock manifold or ported stock manifold is that the air is still routed through the lifter valley, adding heat to the intake charge. This is why we also offer the Cool Gap manifold, it provides a cooler, denser intake charge in maximum power applications - it also allows you to run a 90mm throttle body.

There are now 2 stroker kit options: 511cid (4.5 inch stroke) or 540cid (4.75 inch stroke). The 511 kit drops right in, and the 540 kit requires block clearance work. We just finished one in the Raylar Suburban. We took a 2wd 2500 with a 6.0 / 4L80E and put the 8.1L block with the 540 stroker kit in it. It's got the BP-203 camshaft, stock manifold and ported iron heads like yours. Here's a video of it right after we started it up for the first time with open headers.

Raylar 540 Stroker Kit - Chevy Suburban 2500 - Vortec 8.1 Liter 496 - YouTube

 

I was looking into the 203 cam and was interested in the improvement of torque over the HO cam. I know having a decent amount of over lap and looking for more torque is a fine balancing at. What is the lobe separation of the 203? The HO on a wider 114 isn't helping much for making things happen down low. I saw the video of the burban..can't wait to see what she does on a dyno

 

Performance camshafts aren't so much a down-low torque modification as they are geared toward mid-range / upper RPM horsepower. You will develop more torque with a cam but it usually comes on at a higher RPM because of the advance in the duration. Decreasing lobe separation will make the power come on sooner, but at the expense of driveability. All of our cams are on a 116 lobe separation (with additional advance ground in) this provides a more stock-like driving experience while still providing great power and torque under the curve. 114s sound great, but overlap starts to become an issue with additional duration. Stock and small stall torque converters do not like the rowdier 110/112 lobe separations and buck and surge at low speeds.

You might lose a few ft-lbs of low end torque with BP-203 camshaft, but gain in the mid-range (2000 RPM+). If you're only concerned with off the line grunt, want the vehicle to sound stockish and the truck is used primarily for towing, the BP-202 is what you want. The BP-202 a minor improvement over the HO cam, probably 10-15hp and 20-25hp from the BP-203.

If you're looking for down-low grunt, stroker kits are the way to go. The Suburban is untuned and still feels like it weighs 2000lbs.