Thread: 396 BBC for a truck

Tweet

Welcome to CHR:

If you have stock cast iron oval port heads, aluminum heads can definitely make a difference in the performance of your 396 (now a 408). Depending on your budget, heads can be responsible for 50+ horsepower with no other modifications. Budget is the key here. If you have $2,500, you can purchase AFR 265 heads. Allow another $4 - 500 for incidentals – gaskets, oil, antifreeze, and new head bolts, etc.

The internal combustion engine is a big air pump and these oval port aluminum heads flow an amazing 354 cfm at .65 lift which is huge improvement over stock. Typically aluminum heads will allow a bit more timing as they dissipate heat better than their cast iron counterparts.

I’m assuming that you will be living in the 1,200 – 5,500 RPM range where these heads are a perfect fit. In addition, you’ll save about 35 pounds per head. If you’re going to invest $2,500 in heads by all means, use new head bolts (ARP 135-3703 - $125). Use FelPro 1017-1 gaskets (another $100 per pair).

As to the pushrods – stock intake on 396 is 8.280” and exhaust is 9.250”. Not knowing if your block was decked when bored we can’t determine if different length pushrods were used in reassembly without measuring them. We also don’t know if you are using the stock 1.7 ratio rocker arms. Pushrods should be the last thing you buy. Put the heads on and then use a pushrod checker (as per Roger’s post). New pushrods are available from all the major suppliers in .050” increments. Resist the urge to use anything other than stock rocker arms.

There are less expensive aluminum heads and others will chime in here. If/when you get serious about a purchase; it would also be helpful to know just what camshaft and carburetion you have. If it’s still undecided, I’m a big fan of dual plane, i.e., Edelbrock Performer RPM (or similar) with a big ol’ 800cfm Quadrajet. Nothing is quite like the sound of those secondaries opening up when you stomp on the gas.

Once again, welcome to CHR. More details about what your desired outcome is will help to refine this process. One constant is that building horsepower costs lots of money.

Regards,
Glenn

A big thank you to both of you. Edlebrock manifold, 800cfm, as well as Edlebrock RPM cam I already have. As well as Comp roller rockers. Next I will look into those AFR 265 heads. Again thanks and I will be posting pics of my build as I progress.