been thinking about this for a long time. i have 2 choices with my car. 383 SB or 402 BB. what are the pros and cons of having either in the car. they would put out the same HP and TQ for discussion purposes. i know weight is a factor but they would both be iron block aluminum headed engines.

383, without question. Lighter, better aftermarket support for installing in the car, less cutting/banging/fab, more room in the engine compartment, BBC would need cowl hood, etc.

if you where going to do a bb why not go even bigger a 402 wouldnt be worth it. also how much hp/tq you looking for?

My response was precisely because it's a 402. Maybe 427 or 454, but the difference between 383 and 402 isn't enough to justify the cons of BBC.

For that matter, why settle for 383? 406, 412, 434 - all easy enough to do these day (although not necessarily inexpensive).

The answer will probably be, "Because I have it." And, as is pretty much always true, that's not good enough of a reason.

yea i was going along the same lines as you five7kid. if you already have a 402 and a 383 then 383 but if you are buying it a 402 is not worth it. and the reason i asked about the hp/tq was because you can get the same numbers from a bbc cheaper than a sbc when you start to reach into the 500+ five7kid back me up if its the truth

True, but that wasn't the premise stated by the OP.

Pumping up a 383 to a 406 as a bigger SBC then comparing it to a 402 BBC you won't find much difference in power however the BBC has better potential to make more power mainly from the larger heads. Even factory stock BBC heads are better than mild aftermarket SBC heads. Trying to make a big SBC will cost more than building a small BBC.

A SBC is an easier, cheaper swap but going to a BBC, dropping in a 396 or 402 isn't worth it other than having bragging rights to say you have a BBC under the hood. A 540 has the same external dimensions and will fit anywhere a smaller BBC will fit.

An aluminum head/intake BBC is close to the same weight as an iron head/intake SBC. The little extra the BBC may weigh is easily overcome by the extra torque it creates.

well heres the story. i have a 4 bolt main 350 thats already .030 over ready to go. having a hookup with my friend whos a machinist i can get just about anything for a good price. i also have a late model 366 tall deck truck engine. 4 bolt mains all across, oil cooler line hook ups, roller cam compatible. the plan would be that i can bore the 366 from 3.935 out to 4" and install a late model 502 crank which is 4" and if you do the math it equals a 402. it's also a square engine meaning bore and stroke are the same. after comparing prices of everything i plan on doing to the 350 to make a 550 horse 383 with the price to make a 550 horse 402 they are about equal in just the engine itself. of course i would need diffrent headers oil pan and a bunch of other stuff. i guess my main reason for wanting a BB in my car is novelty and ease of making more HP in the future should i intend to do more head work with diffrent cam selection.

Don't bother with the 366 truck block.

Even if you bore it to 4", the deck will have to be notched to clear the valves of any head that have good flow. And a big cam puts the valves that much closer to the cylinder wall, making a huge restriction.

The 366 is not worth anything except scrap prices or someone with a dump truck that needs a new block. And, you are going to have a tough time getting 450 horses out of that small bore, much less the 550 you want.

I've built many big-blocks and the 366 is like a 267 small-block: Stuff fits it--but why mess with it when there is much better out there.

I would strongly recommend staying small-block in your situation.

(Now, if you had a 427 tall-deck block or 454 block, that statement might be different.)

jms

366 BBC (6L) truck block = garbage. It has zero performance potential. It's not worth investing any money into it.

The 427 truck block is worth doing but tall deck blocks are hard enough to install into a third gen because of even more clearance issues.

When you said 402 BBC, I assumed it was a 396 + .030 which the factory produced and labeled as a 400 BBC. The label confused a few people thinking it was a SBC so it was rebadged as a 402.

402 = 396 + .031" on the bore (4.125").

Gotta keep track of each and every mil, don't ya know.

yea i decided i'm just gonna leave the car small block. after looking into how much it would take to squeeze a bbc in my car it's too much of a pita. gonna keep the big block for a future truck project.