OK, now that I've sold the Z06 and I'm buying my Grand Sport (WildThing) back, I want to treat it to a welcome home present... a stroker motor! My question is, should I go 383 or 396? Are there *really* any pros or cons other than the somewhat higher cost of the 396? Obviously, more cubes is more attractive.

This will be an NA motor with only very occasional duty at the strip. My immediate goal is 450 RWHP which I think is reasonable. I think the current LT4 top end components are good enough already... CNC heads, CNC intake, 222/230 roller cam, 30lb injectors, 52mm throttle body, etc,

More Performance offers a 396 short block with all forged components for $5799 (+ core & freight) but that seems a bit steep. Any other suggestions?

 

:lurk:

If I'm not mistaken, Chuck Wasserott had the MORE 396 LT4 package and dyno'd 510 FWHP with the cam you have in it now. He then went to a CC 306 or something along those lines and picked up another 20 horsepower. I think he preferred the earlier cam though as it was much more streetable.

Hey Hutch, here's a guy selling an entire new 396 LT4 long block in Tampa...
http://forums.corvetteforum.com/zerothread?id=627498

Mike


[Modified by luvmy92, 6:55 PM 8/16/2003]

 

With the 396 i think it is required to get a forged crank. If i am not mistaken you can get a cast crank in a 383 and if you goal is 450hp a forged crank is not necessary especially if you are going to be running naturally aspirated. Check out speed demon motorsports they also offer completed shortblocks.

 

How about a 396 short block group purchase?

 

396 :smash:

 

http://forums.corvetteforum.com/zerothread?id=627498

 

You might want to give Combination Motorsports in Las Vegas a call. They have pretty good prices. You can check them out at http://www.cmotorsports.com
I have been looking, and they seem to have the best combination of performance and value. Good luck.

Darren

 

450rwhp is realistic alright but certainly not with that cam. You'll need something more agreassive. And a bigger TB too, 58mm will be the right choice for a 396.

:cheers:

 

:iagree: I'd look at a comp cams xtreme energy 230/236, .544/.555 or bigger to get 450. http://www.compcams.com/catalog/230.html

 

His 52mm TB flows plenty of air for this combination. The 58mm would be complete overkill. This according to a number of threads on the subject matter. I too am looking at the same scenario and am somewhat leaning towards the 383 at the moment (all forged).

I'm game for a 396 short block GP though. :)

Mike

 

The 396 will have two advantages over the 383. First, it will allow you to run a larger camshaft (duration and overlap) without penalty. How much more I couldn't tell you. Second, the 396 would allow you to have your torque earlier in the RPM band.

Non choice items. HP and torque are only determined by the heads/cam/intake/exhuast. So don't let the Hp goal drive displacement. (Keep in mind that motors must balance three things to keep it in the RPM sweet spot: Intake tuned RPM-alot in LT!/4, Displacement, Head/Cam choice)

Depending on the uysage on the short block...just do a little more reacer porting to the heads (possibly some exoctic coatings), port match intake, and a high lift cam with associated valve train.

Personally I don't you even need your 383 displacement to hit 450 in a LT4. If pocket ported fastburns (gen1 LT4 eddition) will hit 430 on a ZZ4 block with a wimpy LT4 hotcam, why can't yours. :smash: :auto: :conehead :jester

 

thats 450 Rear Wheel hp...not crank.

 

Are we talking 450 flywheel horsepower or rear wheel? There is a huge difference there. Depending on the correction scheme you care to use my 380 rear wheel horsepower can be real close by just using a hot cam and a few other little tricks :) If you want 450 rear wheel horsepower you're gonna need a LOT more than pocked ported heads and a hot cam.

 

Thanks to all for the quick replies.

Mike & Brian -- That built 396 in Tampa sounds great and the photos got my mouth watering but the specs seem like overkill for a street motor. A 258/268 solid roller cam and 12.5:1 CR seem pretty extreme. I want power but not at the expense of being able to drive it comfortably on the street. Given I could sell my current top end components it would make that motor affordable, though.

Something akin to Chuck Wasserott's old setup is what I'm looking for. More's site shows his last numbers at 531HP, 501TQ but I don't know what cam he was running at that point.

Darren -- Thanks for the link to Combination Motorsports. Their $3495 Street 383 motor is probably all that I need but their $4895 Pro Street 396 package is closer to what I want. :D

Half Fast -- Yeh, the Comp Extreme Energy 230/236 cam is probably a good choice. I was hoping to reuse my current 222/230 bumpstick but cams are relatively cheap and I know the 396 can tolerate more cam than a 350.

ZD1 -- Great analysis, thanks, but I still think 450 RWHP NA with stock displacement would be hard to come by and still be livable on the street. 364 to 450 is a big jump.

Nathan -- Yeh, we're talking 450 RWHP minimum. If I can get closer to 500, I'll be all the happier, of course. :yesnod:


[Modified by Hutch, 10:58 AM 8/17/2003]

 

Hutch,

I'm in total agreement in regards to the already built 396. It looks really sweet but it is total overkill for my application. I think Chuck had the CC 306 Cam 230/244 in his car when he was making 531 at the flywheel. You may want to ask him though. A good tune will definitely be in order after installation, that's for sure.

The way I understand it, both the 383 and 396 should have approximately the same horsepower because they have have the same bore (4.030), but the 396 will have more torque (or is it more torque at a lower RPM) because of it's longer stroke (3.875 versus 3.750).

Mike


[Modified by luvmy92, 9:52 AM 8/17/2003]

 

With a solid roller cam in a 396, you can get to 450 RWHP. Most guys that I know that had the solid roller set up's went back to the Hydraulic cams. Have seen 396's with the CC306 get 430RWHP. Have the XE 230/236 cam in my MTI 396 and real happy with it. The 230/236 peaks at 6100 RPM's where the CC306 goes to 6500 RPM's. Have 28# LT4 injectors and 52 TB on my 396.
Put the high flow cats back on as the noise was too much.

 

I am a big fan of the 396 option. I dont know much about cams but i noticed porting and polishing the heads was mentiond. how many cfm do you think you can get with LT4 heads when they are professionally ported and polished? i know its over 300 but im not sure how much. Just out of curiousity why has no one mentioned porting and polishing the LT4 intake manifold? lingenfelter will do it for about 300 bucks. seems like a good deal to me. i would think the cam is the only thing that would really make it unstreetable so since more flow = more power then if you could get more flow from things like intake manifold and heads then you would have more streetability without running a more aggressive cam. just a thought. i have been doing quite a bit of research into this as i am planning on building a 396 stroker eventually. i am looking at using a bit more aggressive of a cam though so it will rev higher but i am still planning on doing all the other things i just mentioned! good luck and keep us up to date on the project! you said your goal was 450-500rwhp? i honestly think that is achievable if you know what you are doing and plan everything out and use quality components

 

I've built quite a few of both and have run both in my 1990... The main advantage the 396 has over the 383 is its broader/fatter torque curve. The additional .125" stroke picks up some additional torque and puts it over a longer range. All things being equal the 396 and the 383 will produce pretty identical horsepower numbers... Bore is horsepower, stroke is torque. My previous 396 was 11.5:1 compression and made 571 hp/505 tq with a solid roller. The only real detractors of the 396 is the short compression height of the pistons when used with 5.850" or 6" rods...This precludes a large use of nitrous oxide or much boost in a forced induction application because you can't drop the ring lands down. The additional stroke also causes increased thrust side wear but with proper cylinder honing and properly file-fit rings it isn't too significant. Additionally it is usually necessary to run a small base circle camshaft with 396's; no big deal really but if you run one (particularly if it's .900 or less) and try to use the OEM height lifters you will find they have to little remaining in the lifter retainers to be comfortable. You have to run a special long body version if you retain OEM style lifters...

383's can be made to produce great horsepower...My wife's car is running a 383 with heavily worked 113 heads and a rather mild hyd. roller cam and is producing 470 hp (that's flywheel). My previous 383 that used the same heads as my 396 but with a BIG hyd. roller instead of the solid and a half point less compression still made almost 550 hp though torque peaked at 470..

Really the main factors are just what you would rather have... There are a couple of companies now building cast iron 3.875" cranks should you decide to stay "budget" but want a 396 anyway...However with the cost of 4340 forged pieces now I would just pony up another few hundred dollars for it. Callies has their "DragonSlayer" line which is in the $800 range and Eagle has one-piece seal 3.875's for less than $600... The Eagle and CAT cranks aren't as pretty as Callies or Cola but they are very good cranks. My company has been cryogenically processing them and we've got a couple of Eagle and CAT big block cranks running in Top Alcohol dragsters for a third the cost of a typical billet T/A crank. So, what you build is simply up to what you want...
-Jeb

 

:iagree: These guys are nothinbg but professional! They are awsome.... Ask for Seth. He will help you with whatever you need. They are always a pleasure to do business with!

 

Question. What sort of RPM does the engine reach peak hp? I'd like a 383 with the peak power around 6000RPM.