My vette isnt really my go fast car so I dont want to set it up with a lumpy idle drag racer feel, but I am thinking of pulling off the heads this winter and doing some home porting, then sending them out for a performance valve job. I have had great success with this formula in the past with porting my own heads and using a smallish camshaft. I was then going to reassemble it with the thinner head gasket and 1.6 rockers in the hope of picking up a bit of power without having a major impact on the driveability or fuel mileage of the car. I have two things I am wondering about. The first is, has anyone else done this ported heads/stock cam combo? How did it work out? The second is, how much compression can I build into the LT1 without causing myself to have a problem with available pump gas? I am certain by the time I unshroud the valves, install new ones etc I will have altered the cc of the chamber somewhat. What should I shoot for on chamber cc? Thanks,
Roy

 

You're probably not gonna find a lot of response on this topic, I know because I've asked the same question. There are a lot of misconceptions about cylinder heads, many people think that you have to have a radical cam to see a performance incresae. People will also tell you that you can see a performance decrease on a stock cam car.

If the heads are ported incorrectly they can hurt performance under any condtions, but with a properly ported setup you can expect pretty good gains with the stock cam.

The LT4 made more power than the LT1 because it had better flowing heads and a more aggressive cam. Most of the difference in the cam though came from the increase in rocker ratio to 1.6. If your heads flow as well as a set of stock LT4 heads and you go with 1.6 rockers you should make similar power to the LT4.

 

Nathan I think that the LT4 is a pretty good analogy of what I can expect with this combo. Thanks for the direction. I guarantee you are right that porting heads makes a big difference even when used with stock camshafts. Been there, done that. Thanks, Roy

 

There's a great book on this very subject, "How to Build Horsepower, Volume 1" by David Vizard. He has porting profiles for all the popular SBC heads including 113 and LT1. His comments about LT1s is that there's not much work to do.

 

Silver and Red, Thanks, I will defiinitely pick that up. I have David Vizards book "How to build and modify Chevrolet Small block cylinder heads" but the version I have was published in 91 and doesnt have any profiles for the LT1 head in it. This book is awesome also.

 

Opps, wrong book. It's "How to Build Max Performance Chevy Small Blocks on a Budget", by Vizard (1999). He covers the Vortec heads, which have the same intake/exhaust ports and combustion chambers as the LT1. Also has lots of basic tips for the SBC heads. From the book, it's pretty obvious the LT1 ports are already really good. A little pocket porting and casting shift clean up gets most of whats left.