racecar

I have a LS6 346 motor now with 11.7:1 compression and a TSP 233/239 .603 lift.
This cam is great for racing and testing on country roads, and I don't have a trailer so I drive it to the track for SCCA races. Any more cam would be a beast in the city, any less would not be enough for the track.
What would be an equal cam for a 427. I'm considering a 4.125 x 4.00 427 with 11 to 1 so I can run pump gas. A 427 would need more lift and duration to have the same feel as my 346. What are you guys using.
I bought the TSP cam after reading about it from many people on this site. No regrets, it's been great. So tell me what are you guys using in 427s.

slow95z

iTrader: (33)

that cam you have would work if you were building one piece by piece like i am doing but a custom cam is the way to go. currently my 427 is sitting in my shop waiting on new heads and i will be going with a new cam, probally custom but i might find something off the shelf that will work (or used on the boards ) so we will see. went i built my 427 back then head options and cam options were limited and extremly expensive is why i went with the setup i did but these days you can get a nice set of heads for dirt cheap and have any cam you want cut from comp to do what you need.

best thing would be to flow test the heads, call up your engine builder, get all the info you can and then sit down and talk to people about a cam. also dont listen to just one person, talk to several and see what they say. sometimes people will try to sell you on a huge cam for peak power when you might want mid range or downlow power. i know its the the exact answer you wanted but thats the best thing you can do.

racecar

OK what are you going to use? You may be right about a custom grind.
The best option that I have seen is a Comp XER287 238/240 .605/.609. I like the lift and duration, but I am thinking it may need more exhaust duration.

slow95z

iTrader: (33)

are you going to keep those LS6 heads?

racecar

Yes I'm using the CNC LS6 heads, I know that LS7 are better, but all of my money is going into a 427 short block.
My LS6 bottom end has a problem with the oil rings so it's time for a change.

RAFTRACER

Why does your LS6 have ring problems ???? Oil consumption or PCV/oil control ???

racecar

Ring Problems; I put in total seal rings in a new honed block. After 1800 miles, I finally have five cyls at 0 leakdown and three at 1-3%, amazingly good numbers, but it still smokes bad on decel. Total seal said it either has to be valve guide seals, or PCV. I put new Viton seals on, no help. Tried a oil seperator from and air compressor in the PCV system, no help. Tried a can with a filter, no help. Vented the motor into a can, it is better on WOT and WOT decel, but it smokes bad at cruise, decel, and idle. Bottom line, the cylinder walls and compression rings are great. The oil rings are not working. If you vent the motor into a can and it smokes bad out the exhaust, something is wrong with the rings. There is no no oil in the can because the compression rings are good.

Patrick G

iTrader: (14)

Here's a ballpark estimate: Add 13 degrees of duration (intake/exhaust) to what you liked on a 346 and this will get you very close on a 427.

racecar

Excellent, that's what I was looking for, to jump up 81 cu in would take 13 degrees of duration to have the same relative amount of cam. Where did you come up with that number? It that a standard from experience, or a calculation.

Patrick G

iTrader: (14)

Mostly from experience. Add 8 degrees of duration for every 50 cubic inch increase. 81/50 = 1.62 x 8 degree = 12.96.

Like I said this is a general ballpark equation. Head flow, intake manifold and exhaust selection will obviously skew the numbers, but you get the general idea.