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Upgrade options for 396 motor

4K views 14 replies 6 participants last post by  dunnhole 
#1 ·
Picked up a 69" with a 396 2-barrel. I want to up the performance a bit by installing a intake and manifold, headers..etc. What is a good combo to use based on a street set-up? I found a older Edelbrock intake C396 model (seller is a pain parting with it). Is this a good manifold for this engine? What type of carburetor would go good as well?
 
#2 ·
As for the carb , if I have a choice of Edelbrock , Holly or Quadrajet , go with the Q-jet (spread bore)
 
#9 · (Edited)
This is an old, old motor. Even if it has had some freshening, that most probably has not been recent.

Freshening the heads, which is pulling them, having the guides and seats inspected, most likely guide work done, replacement rather than knurling, and new springs and keepers. Hardened seats are required for use of unleaded gas, and it is doubtful that this has had hardened seats installed. This is the perfect time to install a moderate cam, any more on a mild motor is not recommended, but a bit more duration and lift will really wake this motor up. To match the cam, you will need to have the appropriate springs to suit. It won't be a bad azz hot rod, but it will sound and feel like it.

Those factory oval port heads are GREAT heads for a moderate big block, way more desirable than big money heads, as the port size is perfect for maximum port velocity. They will respond incredibly well to a moderate cam. If for some reason someone put the rectangular port heads on it, then you will have an issue as they are way too large for a mild motor, they are too large for a hot motor. I put aftermarket 310CC oval port heads on my 502, healthy cam, 10.2:1 compression and it hit 580hp/578tq on the dyno. I took off factory new rectangular port heads (still have them) as they are too large for any use other than WFO 7,000RPM on the drag strip, that's what they were made for. Verify the heads that are on it before you start in. If the ports are too big, then you lose port velocity, and response suffers. Not only that, but you'll need way more cam to 'crutch' the heads, which leads to other problems. Having the correct port size lets you just cam as you need for performance, and the heads will respond to the cam perfectly, speaking for moderate builds here.

As long as you don't increase the compression, you are fine with unleaded regular, timing set to suit, however.

The motor is out of the car, the perfect time to have it gone over, basic freshening, cleaning and painting, and it will be a sight to behold, as well as a healthy, thumpy cruiser for years to come.

Once it's in, it's a PITA to work on, and you probably won't want to, unless you have issues. Doing it now saves on issues and surprises, and lets you install the motor you really wanted in the first place, with some assurance of no problems. If it's got good compression, you're all set.

Do it right, now, then enjoy it.
 
#5 ·
Been away for awhile over the winter...busy with work. Now that spring is near I have to get back into my Impala project. Still looking for a C396 manifold and carb to match for my engine. Not really going to do much that just that swap and possible shorty headers and new exhaust. I'm just looking for a driver while keeping it mostly stock.
 
#6 ·
I know this hasn't seen any posts in a while but I'm looking at doing a 396 build with an sbc. I was wondering what crank you went with, I'm looking at the scat 3.875 with 2.0 rod journal, 6 rods, and 4.040 pistons, just wondering what clearance issues you ran into. If you went with the 2.0 rod journal or 2.1? And if you had to go with a small diameter cam.

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#7 ·
The original poster was talking about a 396 Big Block.

Far as a 396 smallblock, do you understand power is all in the topend, heads and cam control airflow and that is what makes power, displacement can allow bigger heads and cam. A basic 350 with good heads and cam will walk all over a 396 with mediocre heads and cam.

Clearance is dependent on crank/block/rod combination, you will find out when you get it together how much to grind where and how much hammering the oilpan will need.
 
#8 ·
Sorry missed that part, I'm just starting the build so I've been mostly focused on lower end. Picking out right combo and getting together. I plan on getting some good heads and intake just haven't started researching that aspect yet.

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