What is the limit on stock B and RB blocks is it still 700-800 before core shift even with a turbo engine.

 

I don't think anyone here is really qualified to say for sure. They can only give personal experience, but I take that only for what it's worth IMO.

 

core shift is something that happens at the factory, it doesn't happen while the motor's running. Cap walk is the main concern, depending on the block it'll start happening betwee 650-750. In most cases it won't destroy the motor immediately but over time it'll trash the bearings and may cause cracks in the main webs.

The stock caps would have to be changed at more like 650-700 as they usually crack from the cap walk, or in some cases just crack with no cap walk. They're usually the first things to go. Beyond that cracks develop on the sides of the block, around freeze plugs especially. This happens with half filled blocks too.

A few on this site claim the blocks can take in upwards of 1000HP but i'm a bit skeptical on that, i've heard of way too many cases of OEM block destruction at 750ish HP. And these guys are seasoned racers so I think they know how to build motors. If you're going to try to build a high HP turbo motor off a stock block then try one of the new girdles out there, or maybe Dvoraks new cross bolt conversion cap. I still say that'll only help problems not cure it.

 

In Corky Bells book didnt he mention something about how the downward force on the piston during ignition(its not instantaneous there is length of time associated with this event) is more evenly distributed in a forced induced motor while in a naturally aspirated engine it is very peaky. That is why forced induced motors are less stressful on a block than naturally aspirated engines even though they may produce the same horsepower.

He also did mention rpm forces on a con rod, but I think the above would apply more to cap walk.

 

WilliamHall brought up the point that I was wondering about. Are turbo engines easier on blocks?

 

there is a certain supercharged mopar running a aluminum main capped 383 with a stock crank running about 900 crank hp with no major failures yet.

 

I too have heard this theory about the 700 hp "Threshold" .I recently talk to a reputable engine builder, and he also stated that a TURBO is more friendly to the engine if everything is done in effort for a "Turbo" build up.And i think,and correct me if i'm wrong, but most turbo cams are small and power is made down stairs as oppossed to N/A engine, of the same HP/TQ,where Hp and torque are mostly in the upper rpm ranges.Ofcourse i'm comparing a ,Let say, 440 +.03 with standard stroke N/A to Forced induction.

I've got a friend who has been running a stock blocked 440 with all Mopar internals that made over 800hp with a BDS blower, that went for over 8 years getting a woopin, and he finally pulled to freshin it up and found after magnafluxing it had a 1/2" crack in the #2 saddle.That same block is now a +.040 and is running like a dream in my brothers 69 Chrysler 300.Now granted this is not everyone's experience but just food for thought.

Btw this buddy would shift this thing out regularly at 7200.

 

I have one of the least desireable blocks available(75 400 lean burn). It has lasted thru hundreds of 1/4 mile passes. It has been in my car from 1993 , to now, it has been a 400'' motor and a 470'' It has never made less than 700 hp while in my car, and has made 1,045 at the dyno shootout in 2003. The engine has been torn down 4 times for rings, bearings, and once for ''cap walk'' (not torn down for it , but found peppering'black marks') during a freshen up. The time I found peppered surfaces, was the last time it still displaced 400''. At the time I had no idea what caused it, and was lucky enough to find a person who told me it was caused by detonation, and explained why it happens, and not just tell me to get a new billion dollar block. I reduced my timing and it never happened again. The last time I was at the drag strip, I made 12 passes and never opened my hood. By the way, I also use a factory forged crank, now stroked to 3.90, that hasn't broke/ cracked either. There are limits, even if you're carefull, I just haven't reached them yet.

 

trendz , you say your block is undesirable but there is now substansial evidence saying that the later blocks are actually of higher quality than the early pieces.


here is the article on it all.

http://www.440source.com/blockinfo.htm


i definetly trust the factory stuff ...if all these BB guys can run the heavy TRW forged pistons and run through the traps at damn near 7k and go years with out a failure i dont see why i cant use the same parts that will make significant power but never have to go above 5k....

 

RPM kills motors. Turbo motors don't normally require the stupid-high rpm of a N/A motor to make power. Therefore, they live much longer making more power.

 

Take all the info here stir it in a pot and pour some of out use what is left and form your plan.

 

Not to change the subject, but I have often wondered the limits of a stock 360 shortblock. I am looking into a twin turbo setup and would like to see 700 hp. What, if anything, would be insurance to see this happen succesfully. Thanks

 

First, I want to say that I'm sorry for being a bit harsh in some of my replies on this subject. Haze has every right to make up his mind based on what he has seen/heard. The Indy maxx block is an awesome piece that I personally would love to own. It is clearly superior in many aspects, and is a great foundation for a high power big block, this is indisputable. my personal experience has not yet shown me a need for anything other than what I currently have, but I haven't stopped trying to make more power yet!
As for the question on 360 a engines, I think that head gaskets are the biggest problem. With only 4 bolts surrounding each cyl, the chance of blowing a gasket is just that much more likely. Of course, there are solutions, like felpro loc-wire gaskets, cometic steel shim gaskets, or my personal favorite, ''O'' ringed block, copper gasket. I have no personal experience with ''a" engines, so any thing I tell you is just an (un)educated guess. I still believe a large portion of engine durability lies within the ''tune''.

 

Scott Dickenson is running a 383 with 1300 HP with a supercharger. I figure he could run more with turbos. Last time he tore it down, no cap walk and everything still looked like it did when he first put it together. It has to be in the tune, I agree with you Trendz. Why would you one get cap walk all the sudden, unless the tune is boderline. A small change in temperature, humidity, etc... then detonation and cap walk.

 

68RR, that info page on the blocks was very eye opening, I always thought my block was the runt of the litter. thanks!

 

rethinking my whole engine plan...i was set on going with 4340 rods and custom pistons for my turbo 383 but i really dont need it just yet , i want to have a learning combo and if it makes good power and lives all the better.


im going to find a place to align hone the block , bore it with torque plates , get the stock 6.358 rods reconditioned , stud the mains and throw the L2315 TRW's in with a thick cometic gasket and run with it. the pistons are rated a 8.94:1 with an 88cc head and im going to run a .100ish cometic gasket and my stock 452's for about 8.5:1.

it may not be the best quench motor but its what im going to do....it will be a very affordable combo.


is there any other advice you can offer for sometone going the turbo route with a "B" block ?

 

B blocks are a bit stiffer than RBs. You should be fine with your combo.
I'd be tempted to build in more quench instead of dropping a half point of compression. If it's possible to do so in your budget, go for it.

 

Not at all Trendz you aren't out of line. You make some very valid points some of which I hadn't thought of (such as timing) however I don't think timing is the problem, any motor should be able to run 35+ advance without cap walk. However you did not define what you felt was 'too much' timing and how much you retarded yours.

I'm not trying to pimp aftermarket blocks or beat my chest about having one i'm just stating what i've read/heard/seen. I'd just hate for someone to put together a nice motor and scatter it because someone told them it'd be ok. Also 'out of tune' doesn't necessarily mean the motors going to detonate, half the time when people are 'out of tune' they're rich which would soften the blow.

Fuel is not a problem either, there's someone on moparts that recently tore down his mega-block alcohol motor and found his front and rear (the two non-crossbolted mains) to be beating themselves to death. Do you really think he's detonating on alcohol? Granted that's an extreme case from a motor that's putting down some hard numbers (car runs high 8s IIRC). My point though was you CAN have cap walk even without detonation and a tuned motor.

That being said for a majority of the builds going on in this site they seem to be budget ones with relatively inexpensive pieces. Just like alex's mentality, if it blows it blows if not, good . As long as you're not going to hurt anything expensive. I just wouldn't want to see someone spend the $$$ on nice rods, nice pistons, nice heads and have a block blow and trash it all .

 

Haze, I'm glad you dont feel put off by my comments, I think a good debate can open eyes on both sides of the fence. With that being said......YOUR WRONG! If I ran my motor with 35 degrees of ignition lead, I would drive right over my crank after the loud explosion! You can't really believe that! Ignition lead(timing) Is as important as fuel mixture. Timing should be load/rpm dependant. If your friends and seasoned racers are telling you to lock your timing at 35+ and let it rip, you better put rubber rods in that thing to take up the shock, man , That block better be made of kryptonite! You cant be thinking of doing that to a turbo motor, for real, dont do it. As for an alcohol motor not being able to detonate... If it has to much timing,(like your buddy's) it will detonate. Alcohol burns slower than gasoline, which means you need to run more timing, but you can go to far. I can't tell you what timing to run in your motor, but trust me, your friends cant either.

 

alcohol, turbo, blown, N2O, N/A, etc....
Every motor is an individual. They must be treated as such.
Some like a little more timing, others like a little more fuel.
The owner/operator must get a feel for what his motor likes. I can tell you what my original TT440 didn't like. The rebuild is essentially the same but it's more tolerant of timing now. It'll change again when I finish the EFI.

Haze Kid is wrong cause he snatched up a really nifty car and I missed out on it.

Trendz is wrong for some reason. Gimme a little while and I'll make something up.