What does it mean when people rebuild their L98 to a 383? Does it change the look of the motor and I assume it gives your more power? How much more power does it give you and what is the cost? Would like to see a pic of a 383 so I know what you all are talking about. Thanks in advance.

 

Essentially its a 350 with a 400 crank, gives it a longer stroke, hence the term stroker...

 

It's a "350" engine that has had it's 3.48" stroke crankshaft repalced w/a 3.75" stroke crankshaft, and pistons replaced with ones sized to accomdaed a .030" lareger bore.

The 383 originated from the use of a small block chevy 400 crankshaft in a refurbished (the .030" bored) 350 block.

 

A standard 350ci motor has a 4 inch bore and a 3.48" stroke. A 383 is bored out .030 to a 4.030" diameter and the crankshaft stroke is increased to 3.75". This gives the motor a displacement of 383ci. Looks the same inside and out. Needs to be miked to tell the difference in bore and stroke.

 

the increased stroke adds assloads of torque

 

I'm not familiar with that unit of measurement. How much is just one assload? And how many assloads would you say the increased stroke provides?

 

One assload is 1/10 of a Chitload. A 383 with a bigassed cam will generate about 2, maybe 2 1/2 extra Chitloads of SOTP power. Hope this clears up the power thinge.

 

I've heard if the heads are ported, we could be talking 3 extra Chits of power.

 

how much gain would there be going to a 383, but leaving the heads and intake alone? jw

 

Here is a build thats being done for me by Pete K.. This will answer most of your questions..WW

http://forums.corvetteforum.com/c4-t...-w-photos.html

 

Assload is the same as fart power!

 

With an L98 tuned port their would be very little gains. The TPI intake is too small for the 350ci that it has. Thats the reason the 305 i-roc makes almost the same power as the 350 corvette. The L98 heads help alot.

For a 383 stroker TPI you would best benefit form heads, cam and intake. The TPIS miniram intake is great for 383ci engines.

I had a 383 stroker in a 94 firebird with stock ported heads and intake and a LT4 hot cam. And I raced a C4 with a 383ci and a mini ram and the TPIS heads and it walked all over me. The mini ram is a very good intake set up for 383 strokers

 

You already know about the bore/stroke changes from posts prior to this one. And, if not obvious, you can't tell a 350 from a 383 just by looking at one mounted in a car. They will look the same.

If you're rebuilding a 350 shortblock anyway, the extra cost is minimal. But, it still depends on whether you reuse any of your existing rotating assembly (piston, rods, crank). If you were going to replace them all, the extra cost is almost nothing (if you're picking from nice aftermarket parts). If you were going to reuse factory parts, the cost would jump at least an extra $1000 to get all new pistons, rods, and crank. Really nice motors cost even more -- alot more! Or, you can even build a "poor man's 383" using a stock 400 crank. Hopefully, you can see there's no right answer on the cost difference!

Expect about 10% - 15% more power than rebuilding back to a 350. The main difference is that your extra power starts at idle and goes all the way up. Often 350 builds add the majority of their extra power in mid to upper rpm ranges. IOW, if you get an extra 30-40hp out of a 350 build, that numbers represents the extra power at peak. The extra power you gain with a 383 can be all the way from idle to peak. When you length the stroke, the piston moves faster right away -- even at idle. That's because it has to travel a longer distance during the same rotation of the motor.

And, that translates to several chit-loads of grunt-ola -- from the get-go -- to the got-up-and-gone.

 

Sounds like there's a good book in this...Automotive Theory Translated ???

 

A 383 is what almost every 355 build should have been. Practically the same price now too. (Excluding FI and spinners of course.)

Conservative estimate for a small build is you'll make whatever you made with a 350 + the increase in cubic inches. I.E. If you made 300hp with a 350, you make 333hp with a 383. Obviously this is very conservative and what Greg said is true, you make more all over the place which makes it more worth it.

 

How much is crank and pistons? How much extra power .030 boring make?
1 HP?

 

www.summitracing.com - all the parts to do this build all sorts of ways.

If you're going to do it right - get a good set of heads (like AFR's) and an intake like the SuperRam as previously mentioned. Proper cam choice is also important. Of course for it to run best, it will need a custom tune/chip.

Don't forget that the extra torque will raise your stall speed if using an automatic - and if it's an automatic, you better plan on rebuilding it to hold up to all that extra power.

This is the engine I've been researching to build for the C4 I'm wanting to buy this summer. Easy way to get "assloads" of torque compared to stock, and torque is what gets you there quicker. I think this would also be a GREAT way to go if I end up with an LT-1 car