1997 305 to 383 Stroker

Whitebowtie · May 27, 2004

I have a 1997 Chevy with a 305. The oil pump went out, it wiped out the 3 center main bearings, the #6 rod bearing and the crank. The engine has 107,000 miles on it. 7,000 past the extended warranty! This happened about 50-100 miles after I put a remanufatured trans in it. I want to replace the 305 with a 383. I have seen similar swaps, but none exactly like mine. I know I will need to upgrade some things like the injectors and PCM reprogramming to get the most out of the 383. So here are my questions:

1. Will it be drivable with the stock PCM and injectors?

2. Can I get away with using an ajustable fuel pressure gauge to increase the injector flow or do I need to upgrade injectors?

3. If I need to upgrade injectors, what do I need? 350 injectors or after market?

4. Has anyone ever used this place http://www.online-racer.com/chevy_383_stroker.htm ?

maroonsilverado · May 28, 2004

i'd suggest you step up to a 350 block first things first. you can probably find a good late model 350 block for about $200 if you look. you could probably get by stroking a 305 block, but many engine builders will suggest you step up. i hear a 305 is overly sensitive to detonation. too much timing and bad things start happening . and if you started out with a 305 and stroked it using the same components as a 383 you would only get to a 334. what im basically getting at is it would easier, and probably cheaper in the long run, to grab you a 350 block .

now as to answer your questions.......

1. yes, you COULD do it

2. if it were me i'd go ahead and shell out for some bigger injectors to meet the new power needs.

3. 305/350 probably use about the same size injectors, so you wouldn't see much of a gain by going to the stock 350....a good set of aftermarket would be in order.

4. never heard of it.

i believe it's summit that sells a 383 kit......comes with crank, pistons, rods, rings, bearings, etc. basically it's a rebuild kit with the needed parts. hope this helps a little

snoman · May 28, 2004

There are two ways to make a 383 (actual displacement varies a bit with method) One (and the most common) is to use a old 400 small block crank and rods with stock 350 pistons in a 350 block. This is a easy trick but you need to use the harmonic dampner and flexplate/flywheel from a 400 sm because it is a external balance engine while 350 "cranked" engine is internally balanced. The second method is to aquire a 400 sm block (and you need a block for either mod anyway) bore it .030 over and use a stock 305/350 crank and rods which are easy to come by. The plus of this method is engine will rev better with shorter stroke and better rod angularity will develope better power at higher RPM's. An added plus is that engine is internally balanced and your stock dampners and flywheel/flex plates can be used. It makes a real sleeper.

Whitebowtie · May 28, 2004

i'd suggest you step up to a 350 block first things first. you can probably find a good late model 350 block for about $200 if you look. you could probably get by stroking a 305 block, but many engine builders will suggest you step up. i hear a 305 is overly sensitive to detonation. too much timing and bad things start happening . and if you started out with a 305 and stroked it using the same components as a 383 you would only get to a 334. what im basically getting at is it would easier, and probably cheaper in the long run, to grab you a 350 block .

now as to answer your questions.......

1. yes, you COULD do it

2. if it were me i'd go ahead and shell out for some bigger injectors to meet the new power needs.

3. 305/350 probably use about the same size injectors, so you wouldn't see much of a gain by going to the stock 350....a good set of aftermarket would be in order.

4. never heard of it.

i believe it's summit that sells a 383 kit......comes with crank, pistons, rods, rings, bearings, etc. basically it's a rebuild kit with the needed parts. hope this helps a little

Thanks for the reply. I must not have been very clear on my intention. I unfortunately don't have time to build a 383, which I have done about 10 years ago for my 73 Camaro. I am going to replace the 305 with a 383, preferably from the website I listed due to price of $2,199 for the Vortec Longblock. The only things I will use from the 305 is FI, PCM and the bolt-on parts I listed in my sig. Money is the reason I would like to know if it will be drivable with the stock PCM and FI. I will get the PCM reprogram and upgrade the injectors, just can't do it all at once. Right now the wife and I are down to one vehicle and sharing a ride is killing my overtime. Went from 55hrs/week to 40. I need to be able to drive it as soon as possible so I can make some money to get the other upgrades. I just put out almost $2000 for the trans. I prefer to pay cash for my toys. Sorry for rambling, just trying to fill you in on my situation. They have an article on that website I listed from Sport Truck Magazine. But, they replace a 350 not a 305 like I am planning to do, that's my reason for concern. Also, they didn't say anything about the longevity of the engine. I was curious to see if anyone else has bought one from them, to see how it is holding up. Thanks again for the reply.

Joe

Whitebowtie · May 28, 2004

There are two ways to make a 383 (actual displacement varies a bit with method) One (and the most common) is to use a old 400 small block crank and rods with stock 350 pistons in a 350 block. This is a easy trick but you need to use the harmonic dampner and flexplate/flywheel from a 400 sm because it is a external balance engine while 350 "cranked" engine is internally balanced. The second method is to aquire a 400 sm block (and you need a block for either mod anyway) bore it .030 over and use a stock 305/350 crank and rods which are easy to come by. The plus of this method is engine will rev better with shorter stroke and better rod angularity will develope better power at higher RPM's. An added plus is that engine is internally balanced and your stock dampners and flywheel/flex plates can be used. It makes a real sleeper.

There is actually a third option for a 383. Using a 3.800" stroke crank and standard 4.000" bore. GM uses this method for there crate engine here.

snoman · May 28, 2004

There is actually a third option for a 383. Using a 3.800" stroke crank and standard 4.000" bore. GM uses this method for there crate engine here.

I really wonder about that because the old 400 small block was listed as 3.75 stroke and the link you gave states 3.80. I seriously doubt that GM designed a whole new crank with a .050 longer stroke. They suspect that they rounded the old 3.75 up to 3.8 like they round off displacements to the numbers they want. Rest assured that GM does not have 2 different 400 small block cranks based on a 30 year old design as it would have been a terrible waste of money. Nice observation though!

Whitebowtie · May 28, 2004

There is actually a third option for a 383. Using a 3.800" stroke crank and standard 4.000" bore. GM uses this method for there crate engine here.

I really wonder about that because the old 400 small block was listed as 3.75 stroke and the link you gave states 3.80. I seriously doubt that GM designed a whole new crank with a .050 longer stroke. They suspect that they rounded the old 3.75 up to 3.8 like they round off displacements to the numbers they want. Rest assured that GM does not have 2 different 400 small block cranks based on a 30 year old design as it would have been a terrible waste of money. Nice observation though!

If you scroll down you'll see it says Bore x Stroke: 4.00” x 3.80”.

Whitebowtie · May 28, 2004

Here ya go Snoman. Read this. I'm not trying to be a jerk, just sharing some information.

snoman · May 28, 2004

Here ya go Snoman. Read this. I'm not trying to be a jerk, just sharing some information.

Hey I read it the first time and I stand by what i said earlier. Either GM is calling the original 400 crank a 3.80 or is was a 3.8 instead of a 3.75 from day one. It would make no sense to make to crank with a .050 stroke difference and have to make two different replacemeannt pistons with a .025 difference in pin height offset. I was around and driving when the 400 mouse first came out! I good freind of mine used to race them prostock drags and blew a lot of them up untill he settled on a 383 (a 400 block bored 30 over with a 350 crank) and they held together a lot better at higher RPM's. The ones with 400 cranks came apart around 8000 rpm pretty quick with no warning. (usually a piston or a rod and he used good stuff, broke a crank once too)

BTW, you would have to use different rods or pistons because the lengths would be off on compression height if stroke was increased .050 with same rods or pistons as used in old 350/400 combos. Another hot number was a 331 which was a 350 block bored 30 over with a 307 crank ( or large journal 3.25 stroke 327 crank) and 327 pistons. That baby would really wind with right cam. A lets no forget the 302 used in the Z28, a large journal 283 crank for a 4 inch bore 3 inch stroke. They could hit 8000 RPM from the factory! I used to play with this stuff first hand many moons ago man!

Whitebowtie · May 28, 2004

Here ya go Snoman. Read this. I'm not trying to be a jerk, just sharing some information.

Hey I read it the first time and I stand by what i said earlier. Either GM is calling the original 400 crank a 3.80 or is was a 3.8 instead of a 3.75 from day one. It would make no sense to make to crank with a .050 stroke difference and have to make two different replacemeannt pistons with a .025 difference in pin height offset. I was around and driving when the 400 mouse first came out! I good freind of mine used to race them prostock drags and blew a lot of them up untill he settled on a 383 (a 400 block bored 30 over with a 350 crank) and they held together a lot better at higher RPM's. The ones with 400 cranks came apart around 8000 rpm pretty quick with no warning. (usually a piston or a rod and he used good stuff, broke a crank once too)

BTW, you would have to use different rods or pistons because the lengths would be off on compression height if stroke was increased .050 with same rods or pistons as used in old 350/400 combos. Another hot number was a 331 which was a 350 block bored 30 over with a 307 crank ( or large journal 3.25 stroke 327 crank) and 327 pistons. That baby would really wind with right cam. A lets no forget the 302 used in the Z28, a large journal 283 crank for a 4 inch bore 3 inch stroke. They could hit 8000 RPM from the factory! I used to play with this stuff first hand many moons ago man!

You read this? And still don't believe?

For those people that wants a “383 Stroker”, our Race Shop team has come up ZZ450 to fill that need. Our Race Shop starts off with the 383 short block (P/N 12498332) which is a solid platform for our ZZ450. The crankshaft is a forged 4340 steel that could be used in a 600 to 700 horsepower engine. The connecting rods are designed to support power levels up to 550 HP. The new PM rod has proven to be stronger than the older style pink rod. Its four bolt main block and high silicon pistons top off the package. The ZZ450 has a lengthened stroke from 3.48” to 3.800” and keeps the same standard bore of 4.00” (3.800” Stoke x 4.00” Bore = 383 Cubic Inches). The results of all our Race Shop’s efforts were not only to come up with a stroker engine, but also an improved version of the much acclaimed ZZ430. Therefore they named it the ZZ450.

snoman · May 28, 2004

Like I said they may have rounded it off. A 350 is listed in most places as a 3.5 stroke but it is really a 3.48 inch stroke. A 350 corvette is actually around a 345 and no relation to a 350 small block. One would need to get there hands on a old 400 crank and measure true stroke and see what it was. You just cannot make a lot of little change in stroke and have all the stock parts work with a none standard stroke. I was messing with 383 small blocks over 20 years ago man!!!

maroonsilverado · May 28, 2004

oh, lol. sorry about the misunderstanding. i thought you were building one. anyways, maybe that will answer someone else's questions later on down the road

Whitebowtie · May 29, 2004

Like I said they may have rounded it off. A 350 is listed in most places as a 3.5 stroke but it is really a 3.48 inch stroke. A 350 corvette is actually around a 345 and no relation to a 350 small block. One would need to get there hands on a old 400 crank and measure true stroke and see what it was. You just cannot make a lot of little change in stroke and have all the stock parts work with a none standard stroke. I was messing with 383 small blocks over 20 years ago man!!!

How about this it list both 3.800" stroke with 350 mains and a 3.750" stroke with 400 mains?

dfarr · July 10, 2004

building a new engine with vortec heads/ LT1 cam, $1k difference between 350 and 383. questions come to mind is the the 383 a gas hog and will it last as long as the 350? does mopars 383 share similar bore and stroke been told it was a great engine. if the 383 is so great why didn't gm think of it 30 years ago?

Tucson_02Silverado · July 10, 2004

The GMPP 383 truck crate engine is a 3.80 crank with raise pin pistons. No math magic. The cranks are forged/balanced not cast/externally balanced as old 400's.

The balancing is the first clue that they are not the same cranks.