408 SB or 406 BB

Easy build, 408 360 stroker or .030 400 BB. Equally prepped Eddy heads, 850 carb and bracket FT cam- 550 generally I/E. What combo gives me best HP, TQ and longevity? 3200 lbs or less body. Thanks

Bigger bore is more power.

It's that's simple.

The BB has crappy valve placement so it can not take advantage of the big bore like it should, it also weighs #100 more plus asuming an auto trans you have to run the 727 instead of the 904 you can run with a 408 for more weight savings less drag and better 1st gear ratio option and is harder to do plugs and such, I would go SB 408.

Small block all day long. Wouldn't fool with a big block under 500". As mentioned, extra weight, less desirable trans choices.

A small block will be much lighter a 904 transmission will be lighter as well not to mention a lot easier to turn.. a small block with a 4in arm makes tons of torque.... like4like my money would be on the small block with a 4in arm

It might come down to what you have to start with. I haven't built one yet, but here is a combo i think would work well, and cheap, too!
One option is a 400 block, 4.375 bore, offset grind a 383 crank to 3.54 stroke, use 7.10 bb chev h beam rods, shelf stock 1.12 compression height pistons for 426 cheap cubes. Add a .590 MP cam, 2 inch x 40 inch headers. Should make 575 to 600 hp, cheaply.

If these posts would start out saying how quick you would like to go you would get better info. At 3000 pounds if you are happy running high 9's or slower on a budget small block. Low 9's or quicker big block. Small blocks are so much easier to work on for clearance reasons.

10.0 in the heat coast summer, so 9.50-9.7.

3200? Weight or less
Fuel?
Track average adjusted alt? Info available online
Street and strip or strip only?

my vote: SB/904

Well we have a 406 (.030 over 400) in my sons Dart. Its a mild street car that has the 383 forged crank in it. Has RPM heads and 10.5 comp , MP .557 cam and 3.91 gears. 727 with Dynamic 9.5 converter. Runs the Performer RPM intake and 750 DP. Has CPPA headers and 3" exh. Its not lightened any and with his 180 in it the car weighs 3640 lbs. Its run 11.41 @ 117 in full street trim driven to the track. Its one of them we had it so we built it builds. Its not the greatest combo but it runs nice for what it is and is a nice driving car. Here he is at the track. Ron

What car is the engine going in? I'm guessing an A body? If so I'd go for the 408 as a SB is WAY easier to work on than a BB in a A body. I have both, BB car is quicker, but more of a pain to work on.

9.5-9.7@3200lbs??

675-700hp....... with a car that is somewhat sorted out.

One thing to consider is, do you want to reach a certain goal and stay there, or are you someone that wants to go faster as time goes by? If faster is the goal, then focus your sites further down the road.
The two most important rules to follow:
1 weight reduction is cheaper than horsepower
2cubic inches rule
How you put your program together now will have immense effect on your situation down the road.
In my case, another year off racing, and a different course on my engine program and i would be running very low eights instead of 8.90s

How come your limiting the BB to a stock stroke 400? Is it for a cu in limited class? I’m guessing a stroker BB isn’t anymore expensive than a stroker SB. If you’re willing to spend the $$$ on the SB why not the BB? For the hp you’ll need a 4.25” arm in a 400 block will get you there easier.
For that level of HP a BB (stroker or not) would probably be happier/easier, but I have no doubt either combo could hit the number

I'm a big block guy and I say Small Block 408 will be lighter and make the same power.

Depends on the heads for each combo.

I have 408 parts on the shelf and a 400 block with Eddy heads from a RB.Time to try something different or build a 408 with modified W2 heads.Don't know if the 400 will give me anything more than what I have with my present 408 combo, 10.60/122.

I agree with that DusterKid. I tell my son the bigblock A-body is a young mans car since its hard to work on in some area's and the bigblock B-body is an old mans car since it has more room. As for the most part my 63 Sport Fury has more room to work on it then my sons 400 Dart does. Ron

I'm gonna roll with Dusterkid and 383man on this one, I've built and owned multiple bb abodies with both underchassis and fender well Headers, fenderwells are nice for maintenance but unsightly for street exhaust and TTI underchassis are nice Headers to look at but jeez...so...if it's a coin toss on 408 vs 406 I'm going small block, which exactly the decision I made on the 67 Dart I'm building.

Having owned a 9.9 big block, and currently a 9.5 small block..... the lil block is more fun!!

IMO a small block (340/360) with a 4" crank is one of the best bang for the buck engines in the Mopar world. A small block that thinks it's a big block.

If your sure you will always be happy with the results of the SB stroker then go for it
if not think twice about the future now
The reason I suggest that is you can't get much more C.I. out of the stock type 360 or 340 blocks, making a 400 block have 518. C.I. is easy
I've made 514 HP on CA pump gas with a 418 C.I. 340 stroker motor with a set of mildly ported W2 race heads, I made 612 HP with a pump gas 400 stroker motor that was 511 C.I. with a set of OEM iron 906 heads that where mildly ported with larger valves by the same head porter in SO CA
You can make 2.0 HP per C.I. on both types motors, I built a B1 headed 544 C.I. motor that 920 HP on race gas in the Boise, ID area several years back with out a lot of effort on tuning it
You get to choose your type of motor
But I'm a BB guy

I have built a 416 SB and 431 BB,for me it’s BB all day long in a street driven car,it’s a lot like the difference in an old two stroke dirt bike and a four stroke,when you get that two stroke wound up it screams but the four stroke will pull your fat butt around in about any gear and just keep pulling.

I have hated every sb 4-speed car I have owned,doesn’t mean I didn’t have fun with them just preferred the bb grunt for cruising..


Take that 400,drop a 440 crank in it and it will be a lot more fun than the stock stroke version.

A 440 SB is just as easy as a 408 if you need more TQ but I can't even begin to get my 410 SB to hook in my dakota so see no reason to go even more cubes. Min e pulls like mad from idle through about 6500 absolutly no holes in the TQ curve anywhere.

Any main cap walk with the 400? I've experienced it with both a 360 and 408. I just religiously go to an after market main cap and use studs. Solved the problem, but that is an extra cost in materials and machine shop prep. Keeping it under 6400 works too.

I've only built two small block strokers and both have pulled everywhere, gobs of torque.

Agreed you can build a 440" smallblock as easily as a 408, 4.25" crank with 2.00" rod journals makes for a very light (1850-ish gram) bobweight.

That said with the new trick flow 240's out there, I'd like to try a 400 block, 3.52-ish offset ground 383 crank low deck with something like a 6.800" BBC .990 pin rod with the 2.200" journals, I think it would rev as high or higher then the smallblock with the same compression and cam, much bigger valves and it really wouldn't weigh a whole lot more overall, probqbly within 30 pounds of my 440" W2 Iron headed 440" (360 based) smallblock.

The only thing I don't like on SBM's is the lifter angle.

Torque won't be an issue with either combo.

If you want to go 9.50 to 9.70 at 3,000 or heavier, you will need 700 hp? Expensive with a smallblock. You will need great heads, a rollercam, and an aftermarket block. Going with a 400 block will get you the power cheaper. At this stage of performance, weight reduction rule really comes into play. Getting wieght down to 2800 to 2900 pounds from 3200 is going to lower the hp requirements from 700 to 625 or so, much cheaper to get to.