Lets talk Small Block

[TwoFiftyShifter]

The L31 is the hot setup for a 4x4. Need to run an electric fuel pump though. I'd recommend that as a second option to changing to an RV cam in your current motor - like an Edelbrock performer cam.

That 383 would be a monster off idle though

[1972RedNeck]

Originally Posted by TwoFiftyShifter

That 383 would be a monster off idle though

You've never had a big block, have you?

My $.02:

If the engine was built to run on 94 or better, you are going to need to lower the compression. If it were me, I would figure out what thickness headgaskets you have and get a set of gaskets that are a fair bit thicker to drop the compression a touch. Then swap in milder low-end oriented cam while you have the intake off and be done with it.

[TwoFiftyShifter]

Originally Posted by 1972RedNeck

You've never had a big block, have you?

My $.02:

If the engine was built to run on 94 or better, you are going to need to lower the compression. If it were me, I would figure out what thickness headgaskets you have and get a set of gaskets that are a fair bit thicker to drop the compression a touch. Then swap in milder low-end oriented cam while you have the intake off and be done with it.

I've put some miles on a couple different 427s. I have made questionable choices whilst driving it,

I think that Vortec 383 with a peanut cam would be a real torquer from idle rpm.

[Boog]

Originally Posted by TwoFiftyShifter

I have made questionable choices whilst driving it,

Excellent way of putting it. I like that.

[BrianG]

Originally Posted by 1972RedNeck

You've never had a big block, have you?

My $.02:

If the engine was built to run on 94 or better, you are going to need to lower the compression. If it were me, I would figure out what thickness headgaskets you have and get a set of gaskets that are a fair bit thicker to drop the compression a touch. Then swap in milder low-end oriented cam while you have the intake off and be done with it.

Why does the compression ratio need to be lower? I'm not questioning you, I just am trying to learn. I know that I said the guy told me that, and it may be true as far as optimum performance, but I do not get any spark nock what so ever and my timing is not retarted. Will I make more torque, or change the torque curve some how if the compression is lower? Thanks for explaining

[coreyjhen]

Originally Posted by BrianG

Why does the compression ratio need to be lower?

Your compression ratio needs to be lower because of the effect of dynamic compression ratio. You can read up on it several places on the net, but briefly, here's how it works.

Let's assume that you have a 10:1 engine with an Edelbrock Performer RPM cam. That cam closes the intake valve 44º after bottom dead center (ABDC). Plugging your 5.7" rods, 3.48" stroke, 10:1 compression ratio, and no boost into a dynamic compression ratio calculator (I used Wallace Racing's free one), you end up with a dynamic compression ratio of 9.0.

Now, substitute an Performer cam that closes the intake valve at 29º ABDC, and the dynamic compression ratio is 9.6. You will end up with a much more detonation-prone engine, all else being equal.

That is why you will occasionally see people over-cam an engine that has too much compression; it scrubs off some dynamic compression. It's not the ideal solution, but it "kinda" works.