|04-09-2012 12:20 PM|
|jmaine83||350 by far|
|04-09-2012 12:17 PM|
Good stuff here. I agree, 350 is by far, the most popular of the small blocks, and for many good reasons, most of which have already been duscussed.
The original poster asks which is the "strongest" small block. If he means "physical strength" (as in resistance to destruction), 350 most definitely. If he means "most powerful", 400SB (with modifications) is it for obvious reasons.
On the issue of "rod/stroke ratio"... Many high-end engine builders have their own "ideas" about this. Smkey Yunik wanted "as much rod as you can fit in there!" Most agree, 1.7:1 is "ideal" for most performance and drag applications. By no small coincidence, this is the r/s tratio of a 5.7" rod and a 3.25" stroke (327). Hard to argue with the higher rev durability of 327...
A misconception about cylinder pressure and "dwell " is present. "Dwell" (the time the piston is "at rest" between direction changes) is longer with a higher r/s ratio, INCREASING cylinder pressure, not reducing it. It can actually increase the potential for detonation. But it DOES make more power if not detonatng. Added dwell at BDC also improves cylinder "filling" on the intake stroke.
We use 6" rods whenever possible for the 3.75" stroke. Sometimes, budget constraints prevent it. Circle track 350s "like" 6" rods on longer tracks, too.
For ease and availability, 350 is the better choice, IMO.
|04-09-2012 09:14 AM|
|my87Z||I would say that chevrolet knew what they where doing in the fact that they produced the 350 from 1967-2003. I don't know of any other motor that was produced and put in multiple vehicles for 36 consecutive years. That is just flat impressive. Now I personally prefer to built the 383 because of the added tq benifits. But you can buy a simple 5.7L 350 vortec from 96-02' for 400-600.00. Then do some minor head work, intake, carb, cam, headers and you can easily make 350-400hp with a minimal investment.|
|04-09-2012 07:49 AM|
Silver you somewhat threw me off when you mention sticking a 400 shaft in a 350 and having a better rod to stroke ratio. What to you is better?
Lets start out with the basic 350 in stock form
5.703 / 3.480 = 1.63:1
Now a 400:
5.565 / 3.750 = 1.48:1
Budget 383 with stock 400 rods.
5.565 / 3.750 = 1.48:1
383 with 5.7 rods
5.703 / 3.750 = 1.52:1
383 with 6 inch rods
6.000 / 3.750 = 1.6:1
None of these are very good. It's said the optimum rod to stroke for a acceleration engine is 1.8:1 to 1.85:1
Being the most popular 383 combo uses 350 rods, it takes us back to a 1.52:1 ratio. You are right on a longer rod is better, but there are factors in there. longer rods help increase piston dwell time at tdc which helps resist detonation issues in theory by the piston sitting at tdc longer the combusting air/fuel mixture can expand more before the piston moves.
The longer rod also reduces side loading and piston speed.
A example of dwell time is a stock 350 engine, stick a degree wheel on it and a tdc indicator. The dwell time at tdc to 2 to 3 degrees.
Try the experiment again on a 350 with a 6 inch rod, dwell time increases to 8 to 9 degrees. a 6 inch rod in a 350 moves the rod to stroke ratio up to 1.72:1. The lower rod ratio also increases piston side loading into the bore which increases friction and wear. Another issue short rods cause is due to the really low dwell time of the piston at top dead center in the mid range RPMs the piston starts to outrun the flame front. This is especially true in the stock 400 and the 400 rod 383 build. The increased piston speed is also going to put a cap on rpm limit for cast and hyper pistons as they can only take so much before the piston breaks due to the high speed side loading.
|04-08-2012 11:19 PM|
The SBC 350 is (was) the most popular engine in the world for good reason. That popularity has given us zillions of aftermarket parts. The parts and technology have become better and cheaper over time too. It only makes sense to stick with what works.
From there you can add a 400 crank to your 350 and make a 383 stroker and have all the benefits of more cubic inches and a better rod to stroke ratio (long rod engines are better).
400's have their quirks. The smaller displacements seem like a waste of time to me (the power is not there and the aftermarket parts are not there).
|04-08-2012 09:30 PM|
Many of them can be made into respectable runners. The 283, 305, 307, 327, 350 and the 400. However on a popularity scale the 350 is the most popular and parts for it are the cheapest. One thing to keep in mind is the small cubic inchers such as the 283 and the 305 are somewhat more difficult to wring power out of due to there small cubic inches. The 307 is likely the most scorned small block ever but it can easily be made into a strong runner.
If you want a play toy engine then get a 350. As said, good cubic inches, parts common as the day is long, parts cheaper, and just like the rest of the small block family easy to build and easy to hot rod. You don't have to spend alot of money to get 300 horses out of a 350.
|04-08-2012 09:10 PM|
265-400. which out of all sbc family could be a fun engine to have as a play toy? like just doing the basics. cam,intake,headers,heads carb. little stuff.