I've decided a rebuild of my LT1 is in order, and am wanting to go w/a stroker for the rebuild. I really want to get as much out of it (naturally aspirated) as I can, and I'm trying to determine the pro's and con's of each.

ie. What additional machining does a 396 require vs. a 383?
I've noticed that there are alot less cranks to choose from when looking at a 3.875" stroke w/a 6" rod. Is the 383 just more economical from a cost perspective?

Any and all advice is greatly appreciated!

 

It is a little cheaper to build the 383 but with EAGLE parts having the correct crankshaft its pretty economical. You would gain a bit more tq and Hp from the added displacement. Rod to stroke ratio would be a bit off but there are no adverse effects. I have dyno'd 396s and with the right cam and head combination 414 at the wheels isn't to bad

 

Cubic inches rule the street.

 

not just the street!

 

Your wallet, too.

 

Forum member "Diel" should be dynoing his car soon. You may want to see how he does. It should be in the 420-440rwhp range. He has taken no shortcuts! Its a 388 I believe.

 

I hear that a 383 has nearly the ideal stroke/rod ratio, but I've read a number of questionable things about Eagle cranks. I wonder if Scat makes that crank. I don't really want to spend $1200-1800 for a high end crank to get a 396, if that was the case, I'd probably opt for a 383 to save the coin.

Any info on the machining differences for the block? ie additional clearancing? (either way I go, I'll be using I-beam rods)

 

There are only slight differences in the machining/clearancing of the block between 383 and 396. Generally just the pan rail area along the sides of the block (for rod clearance) and the bottom of the cylinder bores (for rod and counterweight clearance).

Build only the amount of cubic inches you need to work with your heads and cam. First you should decide how you want to drive, or race, the car. This will give you a basis for how you need the engine to respond, rev, idle, etc. Your camshaft selection will be closely related to these factors. Then you should decide how much money you are willing to spend on cylinder heads, since this is one of the most important aspects of your engine build-up and ultimate power potential.
If you don't want, or can't have, a larger long duration camshaft, then you probably don't need a 396. Also, if you can't afford high flowing or heavily ported heads with larger runners, you probably don't need a 396.
If you like to road race the car more than drag racing, then you should build a 355 or 383.

As you increase stroke, the rod journals become farther from the main journals, and this makes the crank more sensitive to torsional loading causing deflection. Balance and strength become more important. So, to a certain degree, the longer the stroke...the stronger (or higher quality) the crank should be.

 

I am gathering parts for conv 90 now. His 396 should run strong. He is using all the right pieces

 

was told buy victory racing engines (cool guys build tons of lt1s) that the 396 is no better than the 383 preformance gains are minimal and price are... maximal???

 

Thanks for the response guys, so far my plans are for AFR 210 heads, and I'm thinking in the range of .234 - .238 duration cam, and am aiming for ~11.5CR. The car will continue to be more of a road racer for me than a drag car, so that and keeping decent streetability is what I'm hoping to do. I'm currently leaning towards the 383 though.

 

If you can wait a little while AFR will be releasing their new SBC heads that have incredible flow numbers and potential...give them a call and see what the current release and shipping dates will be. If it were me I would wait...the vast majority of the engines power potential is in the top end...

 

http://forums.corvetteforum.com/show...5&postcount=11

 

I know you'd have to make more clearance for a 396. Money-wise, its really not worth the hassle to the machinist. $2000-$4000 more total on the engine build bill should help you come up with a decision.

383 is just much more common. Or you can get custom cranks ordered and build a 363 or 372. I heard the 363 probably needs to be clearanced just a hair...

 

We definately do more 383s then 396s. Probably 10:1 ratio if not more.

 

I think right now I'd be lucky to have 300 rwhp the tune is so far off the car when it had bolt ons accelerated harder. even my fiancee said that. if she can notice... something is definitely wrong. I'm sure it is in the tune though. Im getting familiar with the gen7 and am learning more and more every single day. i'm taking my time to familiarize myself with every single table that can be adjusted. Mike at DFI-tech line has been very helpful as I've been calling him over and over. A few times he's spent over an hour at a time with me over the phone to help me which is Pretty soon I'll have this baby tuned right. My phone bill is a whole different story

Another budget 383 the shoppe built in an f-body has made 426 rwhp with a much smaller cam than me. I have heads flowing 25 cfm more from .300 up, bigger valves, way way lighter valves, lighter pistons, lighter crank, bigger cam, solid roller valvetrain, titanium rods, electric pump, ati superdamper that's an underdrive, lightweight T&d shaft rockers, bigger headers and exhaust, better intake and much more and my motor will rev almost 2000 rpm higher. SO I'm definitely hoping for more rwhp than him

choosing between a 383 or 396 was easy for me because i wanted the displacement but no more than a 3.75 stroke. bigger strokes just aren't better for higher rpms, although the new z06 makes an argument for that. I went with a bigger bore to help with the airflow around the bigger valves i have. I was after rpm mainly (8000).

If i wasn't building a higher revving motor and was building a hydraulic roller motor i would probably stick with the 383 as well because I don't think the extra expense for 13 more cubes is worth it.

 

Question: if your primary concern is road racing, why not do a 355? You get almost all of the HP, don't lose that much torque, keep your cylinder walls thick, can rev higher, and the costs are significantly less. I'd also say reliability is better, but I don't have anything other than anecdotal evidance to support that claim.

Plus, when you go to a 383 or bigger, you lose ALL excuses when your buddies pass you

No longer can you say "it's a stock motor."

 

It's a pretty well built motor right now, I think it dyno'ed in the 370rwhp range a few years ago. It's got TEA milled/ported heads, 222 cam, 1.6 rockers, header and catback and is tuned well, so it does alright for sure, but I blew a head gasket recently and considering the number of miles it has, I decided I wanted to rebuild and get a little more power out of it at the same time. Money is tight as usual, so I think I can't justify the extra dollars for the 396, I'm sure my wife would agree with that.

 

Don't let money dictate your decision because I bought a 396 shortblock from Golen Engine Service and it only cost me $200 more than the 383.

I was all set to go for a 383 when Golen called me and said I would have to wait for a forged 3.75 crank and, by chance, he had a forged Callies 3.875 crank ready to go. He said the 3.75 and 3.875 cranks cost EXACTLY THE SAME and the extra $200 was for the additional clearancing of the block.

With the 383 plan, I was driving myself nuts trying to choose between a 5.7 rod and 6.0 rod. But with the 396, I chose a Callies 5.85 rod and together with an off the shelf forged SRP piston (-11cc I think) I have an 11:1 CR with LT1 heads (58cc).

I have emissions testing here in Toronto so I had to choose a small cam - 224/224 112 LSA. My heads are LT1 castings ported by TEA with additional port work by Meaux Racing. They flow real well but with my small cam I think I will be lucky to break 400 RWHP. (I am still in the midst of assembling all these pieces).

I fully understand that a 396 would be more suited to a much larger head/cam combo than the one I am planning to bolt on - but for an additional $200 I couldn't resist.

A 383 is for a Dodge.

A 396 is for a Chevy.