General LT-1 Information
Marlin,
First time in this particular section of the forum... Interesting information posted here... Have to check in here more often!
I have a lot of data that you might be interested in. I have always been an early LT-1 nut although the ones that I've owned have always been installed in Corvettes, not Novas. Still, there are many similarities between the two so I think that I might have something useful for you.
First off, I agree with Pete... Your current camshaft is overkill and may actually be costing you some power. I've flow tested several sets of "186" castings and can tell you that even with a great three angle valve job, an unported "186" head starts to run out of flow around .450" lift on the intake port and .475" on the exhaust (compare this to the lift figures of .458" and .485"... the engineers knew what they were doing). There is absolutely no need to lift the valve any higher on an unported head... There just isn't any gain in flow to be had through the intake or exhaust ports.
Regarding the camshaft itself, the LT-1 cam has been discontinued for about a year now. Prior to that, Crane made these under license for GM, so what you were actually getting was a Crane camshaft in GM packaging. Regardless, they were absolutely identical to the original. I had two original LT-1 cams (the first removed from a 1970 Corvette at 1,600 miles, the other at 67,000 miles) as well as a new Crane manufactured GM cam checked on a Cam Doctor at Jere Stahl's shop in York, PA. With the exception of some wear related lift reduction on the 67,000 mile cam (as you would expect), there were no differences in the acceleration or lift curves. The exhaust lobe is identical to exhaust on the old "30-30" cam, but the intake is quite a bit different and accelerates off the base circle at a much faster rate (GM was able to do this because of the use of screw in rocker studs)... There is also quite a bit of overlap designed into the camshaft to make it work with the stock exhaust manifolds... There was a considerable amount of engineering work put into the LT-1 engine.
If you send me your new address Marlin, I will be happy to forward copies of the "186" flow data, the camshaft plots/data as well as some tuning/engineering data that was offered up on another forum by Duke Williams and John Hinckley.
Regards,
Stan Falenski
|