I am posting this because my brother keeps telling me over and over Im a idiot for building a Rb stroker I could be making more power with a low deck stroker. Really is there much difference there in power? What is the main reason to build a low deck over a RB?

1. Shorter stiffer cylinder walls
2. Less weight
3. Stronger main webs
4. shorter push rods
These are just a few right off the top of my head.

Is there really any advantage on power I can see what you are saying there but that almost seems like it would hold up better to high horsepower or bracket engine reliability.

It's stronger yet lighter, a better foundation for a stroker build especially if you are going to build some steam. And 30 or so lbs off the front end couldn't hurt. Shorter, lighter, and stronger push rods and stronger straighter cylinders will make more power. It's just a better choice, not that there is anything wrong with the RB.

The intake selection for a B is limited when compared to a RB.


With that said I went with a low deck. Because of header fitment issues with BS heads.

I personally don't think it about the power, both will make good power, but the low deck is much stronger in the bottom end of the block. I am doing fine with rb stuff but thats what i had to start with.

I also had the Rb stuff to start with .

You can build more cubes with an RB , for the size you went a 400 base would have been a more logical choice , but use what you have .

I went the low deck block route for a couple reasons, but mainly because it fits better in a stock frame/firewall A-body.

- Lower carb height for hood clearance
- Lower and narrower for headers, especially with raised port heads
- If using a factory block, I think the 400 mains webs are slightly stronger
- 4.250" stroke, 511 CID is all I wanted in a factory block
- I use the Indy low deck intake, so that is great they make both B and RB for MaxWedge

For big cube (572) in a chassis car with an aftermarket block, RB is the choice.

I have owned, raced and built both, the low deck 400 blocks might be 5 lbs lighter than a 440 block, maybe not depending on each block The cold weather extra thick main web 400 weigh more than a standard 440 block I had to weigh 4 or more of each size bloxcks to find that out for myself due to the urban myth spread on here about the 400 blocks blocks weighing from 20 to 40 lbs lighter than a 440 block, thats BS I have seen several 440 motor split the main webs, especially between the #1 and # 3 cylinders I have not seen that in a low deck so far I have seen both blocks split cylinders so the choice is yours to make My pump gas 518 low deck stroker made 775 HP on Oregon pump gas last month on a DTS engine dyno, that motor has a set of CNC ported 440-1 heads on it. My 527 C.I. (440 block)high deck bracket motor with 12.8 to 1 compression and a little more camshaft( low deck is 260@.050 int.,266 at .050 EX with .700 lift, the high deck cam is 275 @.050 Int. and 282@.050 EX, similar lift) made the same amount of power on the same dyno last year with the same carb. using 110 octane race gas The bracket motor has a set of indy SR heads that are M.W. intake port sizes from Indy

low deck,low deck,low deck.

For a typical bracket car it really doesn't matter which way you go. I'd be more worried about things like header clearance than the power difference. The RB has more intake manifold options and better main bearing selection. You can also put a longer rod into the RB and the crankshaft is a little stronger.

If I was building Mopar crate motors I'd just go with a nice simple +030 440 block with a 4.250 stroke and call it good. Very simple combination that should work great for most bracket cars.

Cab there is more to an engine than a block. The crank is lighter, the intake, push rods and on some stokers the rods. Here is some facts that you might find interesting.

http://www.arengineering.com/articles/sonicbig.html

When it comes to stroker cranks and aftermarket race rods the same length rods wiegh the same The low deck stroker crank versus the same brand and stroke length in either motor may be 2 to 3 lbs depending on the bob wieghts. My 512-518 low deck stroker pistons weighed 453 grams with no pins, rings , retainers or oil, the 527 pistons weighed 547 grams, if I'm remembering both weights correctly. the 512-518 motor has a set of CAT brand 6.800 long H beam steel rods and the 527 has a set of Manley 6.960 long H beam steel rods, the longest I could buy at that time. I'm sure the longer rod is heavier being both are steel, but both motors made almost the same power even though the 527 has more compression and camshaft I think the better heads outweighed the C.I., compression and camshaft advantage of the RB motor versus the low deck motor Lots of different ways to skin the kitty

It's one of those "it depends" questions.
One issue is what size stroker? You can fit a longer stroke and rods in a RB block, but it is not really an issue unless your talking 4.35"+ strokers.
The 4.25" and smaller stroker engine would give the "B" block a bit of an advantage, but I think the differences might only be important when making over 600 HP? If you plan a stroker making near 800+ HP, use an aftermarket block.

1978 400 351 lbs

1974 440 376 lbs
That is the weight of a LB and a RB short block. Not counting the intake or push rods. Andy weighed them in one of his articles. Add the weight of the push rods and intake and you will with in a pound or so of 30 lbs.

As far as the two examples you gave one RB and one LB they are not even close. How would you deduce that one would be superior over the other or not by two completely different engines. They are not even close.
I hope you have all that information on those two engines where you can copy and paste it to save time. Now where's my Moroso slide-rule 775 hp and.....

I will be using a 440 block with my new eng. And as was said the intake choice is much better for the RB block and since I hope to run the crossram later that made me stay with the RB block. Ron

400 block with 440 steel crank...DONE. Reliable and powerful

I'm really diggin' the 400/512 combo in the Arrow. I have to say I can barely hear the motor working compared to the 446 that it replaced

The advantages of the low deck are spelled out in the above posts..... plus in the case of the 400 block- bigger bore size which helps the heads and top end breathe..............