Thread: 396 BBC for a truck

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Well, this could be an interesting build.

In my opinion, the 7162 could be problematic for several reasons. First off, with modern oils, flat tappet cams require following a very precise break in process. It is essential that you run the engine at 2,000-3,000RPM for at least 20 minutes using a factory recommended 30wt break-in oil that has a zinc additive. The oil should be changed after 200-300 miles and closely inspected for any metallic particles. Even the best engine builders cringe a bit went installing a flat tappet cam for a street engine. I’m far from a professional and I won’t build another flat tappet engine.

I also think the duration and lobe separation on this cam is too much for the street as it comes to life about 2,500 RPM and likes to see 6K+ as an upper limit. It will also have a rough idle. It will need 14 degrees of initial timing to idle (probably 1,000RPM) and maintain enough vacuum for power brakes.

The 700R4 will spend a lot of time in 3rd gear unless you have a 3.93 or 4.11 rear end. You’ll be unhappy with a stall converter under 3,000 RPM.

If you haven’t yet purchased this cam, I’d recommend you consider a roller cam kit like this one from Clay Smith:
https://www.speedwaymotors.com/Clay-...454,80449.html
Duration is a bit less (229/240 versus 240/246 @ .050) but more significant is the lobe separation of 109 degrees will bring the power curve down so that you’ll start to really pull at about 1,800 and see great power at 4K. It would be very comfortable with a 2,500RPM stall converter and would idle well at 700 RPM with an initial timing of 12 degrees and provide more than enough vacuum. Yup, it’s expensive but rollers are, in my opinion, the best way to go for non-professional builds.

Roller rockers are a waste of money for 90% of all street engines – and again, resist the temptation to go beyond 1.7 rockers.

No offense is intended – this is my opinion. I’m hoping Jerry Clayton chimes in here as he is truly the master dragster/racecar builder. If Pat McCarthy (https://www.facebook.com/McCarthyPerformance/) is still reading now and again maybe he will comment. He’s who I’d use if I needed a big block built - I have nothing but the utmost respect for Pat and his knowledge.

Regards,
Glenn

I really do appreciate this information. These are parts I inherited with the motor. Will have to look up the specs on the rockers. I have been hearing a roller cam was the way to go. I will definitely be looking up roller cams and following the pointers you are giving. Thanks a whole lot. Just looking to build a strong reliable 396.