Ok I am looking for suggestions as to which to build. Im going to be starting an engine project soon for my car where i hope to achieve mid 11's NA and spray 10's. I was thinking of going with a forged 355 with LT4 heads sent to lloyed for the LE2 setup but have heard that there is almost no price difference between building a 383 and 355 if you are going with a forged setup. What does everyone think is the price not going to be that much different and is the LE2 setup on these motors even going to get me to where i want to be ET wise. Also im going to be spraying this motor with around a 150 - 200 shot with my nitro daves plate kit to get into the 10's

 

what makes a 355 so much cheaper is the induction in my opinion. A 355 is better suited for fully ported stockers than a 383. To get a 383 to run like it should you need more head & intake to feed the beast. I would even consider running more head on a 355 much less a 383! The actual maching costs aren't that much more unless you use the stock crank than there is worth while savings.

How much money do you have & how fast do you want to go & reliablility do you want it to be, are always the big questions.
-brandon

 

As you stated the cost of a forged crank, whether it's for a 355 or 383, is a wash. There will be however additional machining costs associated with clearancing the block for the stroker crank. You may need higher cost rods that will also not interfere with the stroker setup. I'd talk to the machine shop you plan to have do the work and get a true cost of the difference.

 

A 383 puts limits on a lot of things, the heads need to be able to feed the motor and have enough valve in them so they don't choke the motor.

The valvetrain is more likely to be higher lift which requires better parts to make live.

The bottom end is going to have more piston speed and more TQ which is going to stress it more meaning you really need good parts.

Not to mention the intake being a restriction at high RPM as well.

On the other hand a 355....

Can use a stock crank or a cast steel crank without problems.
Can easily use stock head castings to get you were you want to go in terms of port sizes and valve sizes.
The stock intake is not as much of a restriction.

The best thing to do is go and look at inexpensive 355 setups that run really well. There are a lot of them out there, and not nearly as many 383 setups that match those numbers.

If you are shooting a 150-200 shot a 355 is going to be fine and get the job done for you easily.

Bret

 

I noticed after searching that the crank in the LT1 is good for stock. Can a guy use the stock crank in a rebuild with forged pistons and rods and still make over 600 RWHP (forced induction)?

I noticed that although torque is improved with the 383, peak HP isn't a whole lot higher. Anyone got a dynograph of a 355 vs. 383?

 

The LT1 crank with ARP studs is good to around 600ish fwhp with the proper machine work. On a centrifigually boosted motor, the crank snout is subjected to significant lateral stresses which can cause it tp snap off. This is not a common occurance, but if the boost is turned up high, causing a significant load, it is possible.

 

There is one other factor, IMO. How much fun the car is to drive on a daily basis.

You're gonna notice the extra torque in the 383. Assuming you built 2 motors that both gave you the same ET and trap speed, the 383 is going to be more fun stoplight to stoplight day in and out, IMO. Low RPM grunt just feels great. Need to speed up a little to change lanes going only 40 MPH? Just nudge the gas a little in the 383. You're going to downshift less in the 383 around town.

I know there's more to it than just that, and it depends on the specific engine, etc. But having the torque of the 383 under my right foot consistently puts a grin on my face in daily driving. Having grown up driving bib block muscle cars, there's just no substitute for torque day to day.

As they say, Different strokes for different folks...

 

I guess I feel differently MyZb once you get to the hp level that your break the tires loose in 1st through 3rd gear how much more torque do you really need for the steet. Even the best street tires aren't good enough to meet up w/ the demand. Diff. folks though....hell if I had another 10g's laying around I would go the 383 route, honestly.
-brandon

 

I have to agree totally with that!
I've got stock ported heads and a LT4 hot cam in my 383, and I notice power up top isn't as good as it could be, but the low end torque is great! my truck weighs in around 3900 and with the 3600 stall and 373 gears i can just lay in to the gas without down shifting and it just sets you back. My th400 doesnt have the kickdown hooked up so it wont go back to first gear, but even in second from a 20-30 mph roll just laying into the gas tires go up in smoke.

 

Ok, this post is along the lines of stuff that I have been wondering cause I'd like to do a build-up sometime in the next year. I know that the 383 has more torque than the 355 and that the 383 and the 355 can both run mid 11's NA on a 6-speed. However as also stated, the 383 is more 'fun' to drive.

Supposing that you go with quality parts, wouldn't the 383 be just as reliable as the 355? Would porting the intake allow enough air into the engine for the 383? I want to have good times at the track, but I also want the power there for daily driving. What if I went with a ported LT4 intake matched to my LT1 heads? I was thinking about going with the LE3 setup, but that would probably be too radical in a 355, but more manageable in a 383... Thanks.

Oh yeah, I forgot to mention my goals are the same as his, mid 11's on motor, and a 150-200 shot after that.

 

A friend used stock crank and rods in an LT1 78 Trans Am and developed ~550 RWHP from his times. He weighed 3700 lbs and went 6.94 in 1/8. He was using I think ~12 lbs of boost. He put the same setup in his 87 truck and has a goal of going same time with Nitrous and 18 lbs. I think it will scatter, but her wants to see if it will take it.

So I know stock crank will take 550 RWHP more as far as I know is TBD. Really to me it is important to also consider how long will that setup last. It can take it but will it last? I would go all forged >500 RWHP.


Good luck

 

I like the comment about not being able to hook up the TQ on the street what's the point?

I'm working on a 355 in the shop right now that will torch most 383's anywhere and with some pretty common parts, stock head castings, cast crank, hyd roller. This thing will instantly light up street tires, thank god it's going to run on gumballs most of the time.

Bret

 

Jeremy95...don't worry about reliability with a 383...Now I went a little overboard in my parts selection with the Callies crank, Oliver 5.85 rods, & JE piston combo, but I've got over 10 years of racing/street driving on my motor with zero issues...Just freshened the top end last year with a small Joe O. cam and freshening/addt'l porting of the heads just because I wanted to go faster, but the bottom end compression tested 210-220 in all cylinders so we left it alone...If its built right with quality parts its gonna be reliable...I like the fact that I make tons of power everywhere and only have to spin the motor to 6300 to do it...

--Alan

 

Well, I suppose you could also look at it this way.

When GM wants to put more power in the Vette, what do they do?

5.7L > 6.0L > 7.0L

Ask a new Z06 owner if they wish they could swap their 427 for *less* displacement. Ask Mustang owners all through the '90s if they would have liked more cubes. Ask most guys here who've built a 383 or 396 if they regret it.

Now I know there are plenty of other factors, and there are some fast 355s around, but making categorical statements about "the 355 in your shop that will torch most 383's anywhere" seems a little over the top. I mean, will it torch them anywhere, even in Siberia? How about Lower Slovenia? OK, don't get bent out of shape.....I'm just kiddin' around a little.

The initial poster asked about 355 vs 383. How about owners of both giving him a little feedback without any one person feeling like they have "the" opinion? Seems like that would be cool.

 

They also designed new heads patterned after race cars (Sb2 and C5R) used Ti rods and valves and increased the valve lift another .100"

And yeah I'll stick by the 355 statement. It's not opinions when you deal with enough of these things.

I can do a 383 that will kick *** it just takes more money.

Bret