[Kelvin Poe]

Hi Guys,

I haven’t posted here much lately and thought real hard about not posting this. But, against my better judgment, because of how CV-1 threads normally go, I decided to go ahead and post anyway. I know, aside from the few guys that seem to bash CV-1’s every chance they get, there are a lot of other guys that would be interested in this info. So, here we go.

But, first of all, a big THANKS goes out to Calvin Hill and Jim Sammons for all their help, couldn’t have done it without them.

Anyway, I finally finished up my new CV-1 combo, so here it is. Now, first of all, this was NOT a max effort, all out, heads-up class build, not even close. I’m just a bracket racer and it had been about 6 years since I had done anything other then general maintenance to my engine, so it was time. I went into this as just a simple freshen up and in the process, upgrading my existing KRE Hi-port top end to CV-1’s. I had no horsepower goal in mind, although I was hoping for about 75-100hp over my old combo. Of course, this isn’t meant to be any kind of apples to apples head comparison, so don’t take it as that. I’m just showing my old and new combo and what horsepower I gained from the swap, it’s up to you to do what you want with this info.

Now, my original combo, as you can see most of this in my sig, was an aluminum IA2 block, 525ci (4.310 X 4.500), forged crank, GRP aluminum rods and Ross pistons, all from Butler. Compression was 14:1 with KRE Hi-ports (standard pushrod location), and a BOP intake, both heads and intake ported by Dan Barton, with the heads flowing 388cfm, BOP belt drive and a 1250 dominator on alcohol. The cam was a Comp cam 4-7 swap with .471 lobe lift and 285/288 duration at .050 on a 110 centerline and running 1.65 rockers. This combo dyno’d at 822hp @ 6800rpm and 719tq @ 5500rpm.

For the new combo we had to go to a 4.325 bore to clean it up, same 4.500 stroke crank, which makes it a 529ci. The rods were due to be replaced, but I stuck with the GRP rods and went with Diamond pistons. I had to go with a slight dome (about .060) on the pistons to keep the compression at 14:1, because of the slightly bigger combustion chambers of the CV-1 heads. The heads are Calvin Hill’s Fusion port 435cfm versions, and Rolands cast tunnel ram. Had to replace the cam also, because the old one was showing some flaking on a couple of the lobes. But, I stuck with the Comp cam and a .471 lobe lift. The duration is now 285/300 at .050, 114 centerline and a standard Pontiac firing order, No 4-7 swap. Still on alcohol with the same carb and headers.

Now to the dyno, with turned out much better then I anticipated. The last pull we made, which was also the best, ended at 974hp @ 7300rpm, 760ftlbs. tq @ 6000rpm with the timing set at 34. We played with the timing everywhere from 25 to 36, and 34 is where it like it. We initially degreed the cam in on the stand and never played with cam timing on the dyno. That’s an increase of more then 150hp with basically just a top end swap. We could have kept going and gotten a little more out of it, but I was more then happy with that and it was getting late, so we called it good. As I said, this is just a bracket combo and I wasn’t worried about trying to get every last ounce of power out of it.

Again, this is NOT intended to be an apples to apples head comparison, so don’t take it as that.

I’ll be more then happy to answer any and all questions about this combo, but if this thread starts going south like all the other CV-1 threads, then I’m out.

Kelvin