gt1guy
Apparently a racist
Ya, that is me. It's a R07. The R07 replaced the SB2. Ford has their version and so does Dodge and so does Toyota. They're all badass engines.
I don't know why more racers aren't using them over the LS's. Could have something to do with the fact that outside of NASCAR, they don't really exist. The bare unported heads and compacted graphite blocks only come from GM. They're very expensive and don't show up even in the performance parts catalogs. That shouldn't be a hindrance to any known race engine builder though, they ain't top secrete. You just don't hear thhem mentioned very often.
They have certainly proven themselves to put out more than 900hp and run flat out for hours on end. They've been EFI with a 4bbl TB for years now.
If there is one draw back to them, it's that they are designed to run solid flat tappet lifters. That a NASCAR rule.
But like you said, they are designed to oil cool the valve springs and pistons.The valve springs actually sit down in pockets that fill with oil from the spray bars. That also dampens any harmonics in the valve springs. The cam is raised 1.4" if I remember right. So shorter pushrods and better geometry.
I might be picking up a compacted graphite block in a couple months. Nothing wrong with it, just needs the bores cleaned up and it's at the (1.85") bore limit of the rules so it can't be used. I already have everything to build it minus pistons, rods, pins and rings. Would be cool in the 69 Camaro.
The billet R07 block I have has a few modifications designed into it because I don't have to follow a rule book. Set up for .904 keyway roller lifters, taller deck height. Oiling system modified so it doesn't flood the lifter valley in oil cause no solid lifters). Lg journal SBC main size.
4.250"bore x 3.750" stroke should make for a screaming 425cid
Edit: I forgot probably the best part of the R07 design. They have a 4.5" bore spacing compared to the LS/SBC 4.4" bore spacing.That allows for better cooling between the cylinder walls. In My case with the billet block with liners in it, I am able to punch it out to 4.250" and still have .250" between cylinder walls. Most of the big cube LS's end up with a really long stroke and paper thin cylinder walls.
And one last thing is that the intake ports in the heads are asymmetrically placed so each manifold runner is exactly the same length. That tidbit I don't care about because I plan to run a Kinsler IR DBW intake set up and boost.
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