Better for towing? 396, 402, 427 (closed chamber) vs. 454 (open chamber)

[cwilkie]

Does anyone know if a 402bb or a 454bb is better for towing and pulling on a 1972 Chevy 3/4 ton 4x4? I think the 396, 402, & 427 had closed chamber heads for higher compression but the 454 had open chamber heads for lower compression. What are your opinions and/or experiences?

[GASoline71]

No replacement for displacement... especially for towing. More torque.

Gary

[Shyguy]

I am interested in this one since I have a 454 in my '71. My '92 K-3500 has a 454 and it tows pretty good. I normally tow a 8400 pound travel trailer with it.

[cwilkie]

I am asking because I want to know which engine block to go after. I already have one set of closed chamber heads and one set of open chamber heads. Pump gas will be an issue as well.

[vectorit]

My favorite...

396, 402, or a 427 with semi open chamber heads added with a dual plain intake manifold. Add SM465, low gears like 4.11 or 4.56 to the mix and I'd be a happy man.

I like the stroke of those three, which are all the same just varying size bores.

Get the early style semi opens, typically late 60's early 70's vintage. They will have the large oval ports instead of the later smaller smog models.

[Jtrux]

I vote 454, closed chamber, dual plane intake like Edelbrock, maybe even the air-gap variety, 9:1 compression hypereutectic pistons. This would be a good tow machine. Big RV cam and you would be set.

[QKENUF4U]

no replacement for displacement as said above but its gonna be all about your CAM/INTAKE more than anything... do some reading about duration/lift etc. and make a choice that will work for what you intend to do with the truck...

[Duncan and son]

We like em original but the only substitute for cubic inches is cubic dollars.

[prostreetC-10]

Absolutely the 454. You have a longer stroke which = torque. I really need to do a vid or two of the truck below. It's our ranch/hay truck. I built a 454 for it about 3 years ago. Here are the specs:

454 with flat tops
781 early open heads
crane 270H .515/.515 cam
older Ed. performer 2.0 intake
Holley 3310 (built by me ;xD)
1 7/8th headers with dual exhaust and H pipe
TH400

This thing is a freaking torque monster. Some think that cam isn't an RV cam. It's more into the performance area. Not so. This was recommended by Harold Brookshire from Ultradyne Cams (I believe he is now heading up Lunati) who is one of the greatest cam designers of all time. He runs this cam profile in all of his 454 race car tow vehicles. I thought it might have been too big for an RV cam at first but this thing rips. Unreal torque and it hammers pretty good out the back.

As far as the heads go. Forget the closed chambered heads. You are trying to build torque not HP. My prostreet truck had 781 opens on it and I made the mistake of putting on 702 '65-'66 395/427 closed heads. Bumping up compression will not help your towing like you think because you are giving up intake runner size. I'm at around 10.25:1 comp and wish I still had the 781's on it. The 781s and the 049s are just about the best iron oval port heads you can run on a big block.

I'm also running about 18* initial timing. These BBC's love a lot of initial.

[turp mcspray]

One more thing. The closed chambers will bump compression, but they severely shroud the valves, which hurts airflow.

[GRX]

Originally Posted by turp mcspray

One more thing. The closed chambers will bump compression, but they severely shroud the valves, which hurts airflow.

This - ^^^

[prostreetC-10]

This is why the best senario is the get an old motor that needs rebuilt but has the bigger open heads and just get a piston with a slight dome to bump the compression. Quite frankly them stock flat tops with the 781's or 049's will make MORE than enough towing torque though. This is why the famous early 454 is so hard to beat. This is why I don't own a small block. All you gotta do is open them up just a bit on the top and bottom (get them to breathe) and put a decent cam in them. Ground pounding fun all day long.

['72customdeluxe]

*flame suit on* you might consider peanut ports on a tow rig.
Check out the latest car craft, made 446/542 (good even if the numbers are inflated) with those and an xe268 in a 454. I've read alot about success stories with those for a torquey motor

[Davetopay]

Originally Posted by Jtrux

I vote 454, closed chamber, dual plane intake like Edelbrock, maybe even the air-gap variety, 9:1 compression hypereutectic pistons. This would be a good tow machine. Big RV cam and you would be set.

Closed chambers will build compression, but don't breathe worth a damn. The valves are shrouded by the chamber walls.

[Davetopay]

Originally Posted by turp mcspray

One more thing. The closed chambers will bump compression, but they severely shroud the valves, which hurts airflow.

Damn....beat me to it!!!!

[prostreetC-10]

Also remember that the valves are shrouded by the walls of the closed heads.

The other thing is that the closed chambers will effect the valves.....will actually "shroud" them!

LMAO.......sorry, couldn't resist the smart a$$ comment!

[Davetopay]

Originally Posted by prostreetC-10

Also remember that the valves are shrouded by the walls of the closed heads.

The other thing is that the closed chambers will effect the valves.....will actually "shroud" them!

LMAO.......sorry, couldn't resist the smart a$$ comment!

It's what I get for not reading every post before I chime in.

[prostreetC-10]

Believe me.......I do it all the time. That's why I thought it was so funny.