i currently have a stock 396 engine with a TH350 tranny, qjet carb, 2500 stall, 3.73 gears i think.
i dont know what type of cam or heads or pistons i got in the engine cause i lost the specs sheet.

what can i do to build up the torque keeping in mind that i will be installing a 454 after this engine gives out.

some wild nitrous starting at 2500 rpms...100 shot =over 200lb ft @2500

Building torque is done by matching dynamic compression ratio with intake valve closing timing! And then making sure that you aren't too big on stuff like too big of intake port heads or primary header pipe diameter or carb.!

(I think the magic DCR number seems to be around 8 to 1 with cast-iron heads and 92 octane pump gas unless you really work with your combination..)

And as you go up in cam duration, you have to watch static compression or you can lower the dynamic compression so much that your motor ends up being a dog!

All b/c you can't up it's static compression b/c you can't buy good high octane pump gas anymore to feed a high compression motor like we used to be able to years ago!!

This is just a rough start. I suggest buying a copy of Ed Staffel's BB book, "How to Build Max Performance Chevy Rat Motors", b/c it has a bunch of good info on this subject in it..

pdq67

Another way to describe TQ is cylinder pressure. So anything you can do to increase cylinder pressure will increase TQ. The problem of course is that too much cylinder pressure causes detonation, so like PDQ said you have to match the compression ratio and camshaft.

In general, a higher compression ratio, smaller intake ports that create a high velocity, dual plane intakes, smaller carbs with a strong signal, and smaller camshafts all help to build low end TQ.

IMO On a 396 this means oval port heads with closed chambers and either small dome pistons or flat top pistons. A good valve job and good port work will also help TQ -- you don't have to hog out ports and kill velocity to make them flow good.

Knowing your cranking compression will give you a clue as to how much cylinder pressure it has. Without knowing the cam , you're at a real disadvantage. However, to get real good grunt out of a small displacement engine, you hope to have a cranking compression north of, say, 170 psi. At around 200, you start to make some good power.

Actually, cylinder pressure during operation is different then a cylinder pressure test.

The engines own ability to fill the cylinder plays a big part in it.