The Stovebolt Site Forums The Shop Area The HiPo Shop 427 Tall Deck... Pros and Cons?

For all you High Octane boys in the crowd, what is the deal with this motor?

56GMCRat

366 396 402 and 427 truck motors. Guys building big inch strokers sometimes use them. The taller deck moves the heads up and out,so you need more space. Uses a differant intake and distributer. all I know about them.

Only amde in the 366 and 427 cid, no 396, 402, or 454. GM did make a few 500+ cid crate engines based on that block, also the DRCE pro stock block is based on it. The only real pro to using the tall deck on a street engine would be if you're going for big cubes (600+), otherwise, it's just extra weight. As HevyHaler stated, they use a different intake and distributor. This is due to the taller deck hight. Not much in the line of intakes being made, I have seen stock bbc intakes made to fit using spacers. If you're looking at one (I recall from another post you were), if the price is good (Cheap/free) it will work fine and be a good stout engine. Just don't expect to make a hi-power screamer out of it without doing some serious race type mods.

I see... It was a great price, but I was looking to make a hot street motor out of it.

I have done research in the last hour of so and found that the tall deck is a 4 bolt main, which not all bbc are, and comes factory with a forged steel crank...

I would like to build it 450+ hp, but still would like to keep it streetable... Would I be better off trading for a regular bbc?

Not necessarily. The tall deck is a good engine, especially if you want to build a stroker engine. You could put a longer stroke crank, or have the original stroked at the machine shop, and pick ip alot of torque and hp and still keep it on pump gas. The only real major hangup would be any parts that rely on the block hight/width, such as the cam drive, intake, pushrods, and the distributor. Only the intake might have some availabilty issues. Check out Summit or Jegs. You should be able to find parts there for hopping up that block.
As far as a space issue, it shouldn't be much different than a standard big block, might be a little better on the exhaust side due to being higher. Before you redo the block, strip it dowm to bare block (easier to handle) and mock it up in the frame to see where there's any clearance issues so you won't have any surpises.
I guess what I'm trying to say is go for it. You can make a good steetable torque monster with that block, and as I said, keep it on pump gas.

That is perfect LONGBOX! Just what I needed to know. I did not even think about JEGs. This is exactly why I am apart of this site. Thank you again.

Now, what should I do about the front end to suport the bbc?

From what I have found there is not a lot of difference in weight between a BB and our 216,235,and 261s. Not long ago I asked the weight of a 261 and was shocked.

Do you remember the weight? I would like to know...

Hey 56

If all you are looking for is 450 - 500Hp why not build a 400 sbc and not take the weight hit. As someone said in an earlier post, those blocks were some times used to build big inch strokers, if your going to only have 427ci its not worth it. Just my 2 cents.

Sean

The tall deck block is 5/8 taller.It will except an overbore around .160 .Install a 454 shaft , stock length rods,custom set of pistons and you have 496 inches.It has been along time since I have done this but if I remember right Venolia or Keith Black make the pistons.You might inquire about piston heights from the manufacture to get your compression ratio where you want it.Cheap stroker.

Wow, I had no idea it would be that easy to stroke. I might just do that. The weight of the motor is really not that big of a difference (50# from the 235), so I think I will stay with it. I am too excited!

Tallblock pros and cons
pros: tons-o-torque
cons: won't rev for long
Or you can build a 496 stroker,run 8:1 forged pistons and an 8-71 blower at 10% underdriven and make some really impressive torque.
Speed

Just a piece of advice from a person who has spent all the inheritance money of his rich uncle when he got out of the "poor house".
"There is no substitute for cubic inches except cubic money!"

As far as the tall decks go in stock form , once you get that 80lb flywheel off of it & get rid of the govenor carb it does pretty good . We put a few of them in 1/2&3/4 ton pickups with good results. Change camshaft and a set ot headers does wonders. Some of them have tiny valves and a
head change really helps. All said they make a great torque motor. Around here you can find them pretty easy [ cental Pa. ]
Have A Good Day --- Fergy

good heads and a matching cam can easily put you over 500 hp with the stock stroke