Help with a 396 build in a work truck

[5akman]

I posted this last year about a 1894 K20 rebuild for use on the beach in AK hauling fish. That truck project is finished and running fine.

I now have 1980 K20 with wrecking yard BBC in it. I thought it was a 454 but block casting numbers show to be a 1970 396/402 truck motor with -950 heads. I'm not opposed to building the 396 but would need build specs for a low rpm torque monster engine for use again on the beach hauling fish.

I have some 236 peanut port heads with mild bowl work/porting and I read where they are good for this application. I'd like advice on piston and cam options for use with the PP heads and this particular use. There is not much out there for reference!

Other option is to sell the running 396 and either rebuild a SBC or buy a GM crate engine and do some cam mods. Is that 396 worth anything on the used market?

 

[4WDKC]

It might be worth something to someone restoring a truck of that era. The problem I have been seeing with everything associated with low rpm torque monsters is they are usually out of steam by 4000 rpm. With a stock stall that is 15-1800 rpm that leave you 2.2k of usable rpm,that is not enough and how the 454 TBI trucks got a bad reputation for no power,over heating and slow. There is a video somewhere they dyno a high torque low rpm engine then change the cam to higher rpm hp cam < 6k rpm, it made the same torque in the low rpm but had the capability to pull higher rpm. This would allow you to downshift to pull a hill with a load and maintain or gain speed, instead of going slower while overheating.

 

[Honky Kong jr]

It's a 402 not a 396. In 70 the real 396s were gone whether it was badged a 396,400 it was indeed a 402 I'd throw them PP heads away ....wait I always do. Used Big Block heads are way cheaper then they used to be hell BBC engines are for that matter with the exception of a few regard that think they are gold at any rate thanks LS guys.lol

 

[4WDKC]

It's a 402 not a 396. In 70 the real 396s were gone whether it was badged a 396,400 it was indeed a 402 I'd throw them PP heads away ....wait I always do. Used Big Block heads are way cheaper then they used to be hell BBC engines are for that matter with the exception of a few regard that think they are gold at any rate thanks LS guys.lol

it seems like that till you check out the towing forums where they all bash the ls for mid to heavy towing. Have a vortec 454 swap waiting for the 350 or 700r4 to quit in my truck.

 

[Honky Kong jr]

it seems like that till you check out the towing forums where they all bash the ls for mid to heavy towing. Have a vortec 454 swap waiting for the 350 or 700r4 to quit in my truck.

Yeah for torque for towing you want a big block but hot riders now a days go with LS instead of big blocks making them cheaper which I like but then again I get them by the pound lol

 

[5akman]

Thanks for all the info. I'll try selling the running bbc first, and if it doesn't sell, plan on the torque monster rebuild

 

[Honky Kong jr]

Thanks for all the info. I'll try selling the running bbc first, and if it doesn't sell, plan on the torque monster rebuild

Although a 402 is a big block it wasn't a torque monster but they like rpm if built right. Still torquier then a small block tho. I like my 407 30 over 402. Or 60 396 either way the same chicken.

 

[74 Shortbed]

The 396/402 is a total waste, they are a "big block" with small cubes, but it's still a "big block" when it comes building one, you can build an off idle parts breaking 468 for the same cost as a 396..

 

[Honky Kong jr]

The 396/402 is a total waste, they are a "big block" with small cubes, but it's still a "big block" when it comes building one, you can build an off idle parts breaking 468 for the same cost as a 396..

So I guess I'm safe then as far as breaking stuff then.

 

[74 Shortbed]

So I guess I'm safe then as far as breaking stuff then.

Well, if you have a 396 yes you don't have to worry about breaking stuff, lol

 

[shiftpro]

Interesting thread...
I wonder if big cubes can cam up a little higher than the 'zone' we want to run.
You know the 'young' guys that would over cam an engine..?
Maybe a little of that on a big block won't actually cause such a loss on the bottom as say,
a sbc would?

And I'm referring to building a torque monster work/DD as the OP (thank you) brought up.

I'm very interested in this subject as I'm trying to come up with the perfect cam specs for my 496 build.
Like, do I really need a cam that begins at 1000 and steps away at 4000?
Maybe something more sporty that begins at 2000 and howls until 5500 would suffice without robbing anything
below that?

 

[shiftpro]

Oh and if your heads can't flow **** after 3500 forget it... right?

But there are better BB heads out there yes..!

And porting and bigger valves is easy peasy.

Or $$ and aftermarket alum heads...

 

[shiftpro]

And I prefer iron GM blocks over LS.
Around my woods the LS mills are NOT cheap.
They can keep 'em... along with their FI too.

 

[shiftpro]

Can one stroke a 396?
Is it worth it? Is it relative?
I guess depends where you are planted and the sources close enough by.
Oh and if you're by chance a millennial you might think an engine without a stinkin computer
will never run...!lol

 

[shiftpro]

Sorry guys don't mean to highjack the thread.