I'm running a 236/242 cam in my 383 and it avgerages about 10 inches of vaccum at the manifold. My question is, is this enough vaccum to prevent blow by or blowing the seals? It's a brand new motor and its already leaking oil from what looks like the front main seal. This was the only thing I could figure out.

As far as the rear end goes, how do I figure out what the best gear ratio would be for my rear end? It feels like I'm shifting right out of my power band. Do I need to have it dyno'd first to find out where my peak power is?
It's a stock rear end.
Thanks

 

Can anyone answer my questions?

 

Let's try it on "LT1 Engine Tech".

 

I've got a 396 w/ 232/242 spec'd cam. New it had 14" of vac but now I only get 11 or so. Really couldn't answer you question in regards to blow by but I've blown 2 rear seals in this thing already w/ less than 3K on the engine. Running the same clutch but a alum flywheel and 3.23 gears in my M6....autobahn purposes. But I know what you are talking about when it comes to the pwr band issue. 3.73's are goin in shortly on my 10bolt. Worst case I break them and put the 3.23s back in they've lasted 2 rebuilds thus far on the 396.

Hope someone can help answer your questions as I'm curious to know the answer myself.

 

WAsnt sure if it was advanced or not. THanks Injuneer

 

Trying again

 

My vacuum was around 10" last time I checked it. I have not had any problems with leaks yet. I only have 1800 miles on the new motor.

I really like my 4.10's. I have been told by several drag racers that they are the right gears for heavy street cars with lots of power.


Mark

 

I dont really know the part numbers all that well. What are the specs on your cam 96TAblur

 

I'm running the same cam in my stock-bottom ended/heads car and am getting about 11.5" of vacuum at idle. Just enough to keep the power brakes comfortable.