The Stovebolt Site Forums The Parking Lot '60-'66 Trucks 396 Engine

Have any of you had experience with a 396 in one of these trucks? As I've mentioned, I am putting in a 3.54 Dana 60 that came out of a 1968 C20 Suburban. Those C20 Suburbans got the 396/TH400/3.54 D60. I was going to install a vortec 350, but I am wanting more torque, and am looking at a 396. My truck will have the Ranger Overdrive, SM420, and Dana 60.

Blueprinted and balanced they will last forever. They will, however, not pass a gas station. 🤣

I was thinking with a good torquey cam rated from idle or 1,000 to 5,000 rpms, along with good gearing to keep the cruising rpms between 2,000 and 2,600, or wherever the sweet spot rpm is for the engine to make maximum vacuum at cruise, that would allow minimal gas pedal to keep the beast moving along. Whereas a 350 needs more pedal to get the power. I talked to a guy last year that has a C20 Suburban and he said it can get 25 mpg's. Maybe he was pulling my leg. I do know when I ran the 3.54 rear in my other '65 with a stock 350, it consistently got 14-16 doing 70 down the road.

Being high torque made me think of the big boat cars like Oldsmobile, Cadillac, with their big blocks and the good mileage they got while cruising at decent speeds.

My father put an LS6 454 into his 66 GMC in place of the 6 cylinder.

DD, make the guy pull your other leg to even them out. I’ve had a few 396’s and 454’s over the years and 10 mpg was the norm, uphill, down hill, with the wind or against it. All the same.

I'm not into fads, and the LS craze is a fad. No LS will ever be installed into any of my vehicles if they didn't come with one from the factory. If someone else wants to do it, I'll let them, it's not my money. Thanks for the input though. The LS does make great power and gets good mileage, but again, fad.

I also asked my stepdad (Pop) because he was a mechanic for most of his life and saw nearly every conceivable car they made back in the day. I talked to him last night, and he basically said what you're saying. Great engine that never got good mileage no matter how you had it setup. He said with today's crappy gas it'll make it worse. Not like the old days when you could get super premium leaded at Union 76 that was purple from the nozzle. He said the only way to get good mileage out of it would be to boost the octane a lot, but then it really hurts the wallet.

So after much thought, it looks like vortec 350 has one out on this one. I put vortec heads on the engine in my '81 3/4 ton and it has good power with 4.10 gears. A stock 350 can push the 3.54's just fine, so a vortec should be able do better.

Thanks everyone for steering me away from the 396 and back to the vortec 350.