383 Stroker

[mud hungry]

Can anyone tell me exactly what a 383 stroker. Is it a seperate engine or is it a 350 with longer piston rods to it? I know it is a newbie question sorry. Also what king of horse power would you get out of it if it was mildly built. Thanks

 

[Mad-Dog]

A 383 stroker is a 350 block with a 400 crank to be blunt...
The 350 has a 3.48" stoke and a 4.00" bore,
the 400 has a 3.75" stroke and 4.125" bore,
350 rods are 5.7" long center to center,
400 rods are 5.565' long center to center,

First you need to know that the rod ratio is calculated by dividing the length of the connecting by the length of the stroke...example: 5.7" / 3.48 = 1.62:1

common 383's use a 3.75" stroker crank, 350 block and 5.7" (350) rods.
This particular combination has a very poor rod ratio (1.52:1) and does not like to rev over 5500rpm, the ideal rod ratio is (1.75:1) but cant be be done to a 383 unless you acquire a tall deck block because the rods would have to be over 6.5" long and that would place the piston pin at the top of the piston (talk about dwell time.....wow)

I am presently having a 383 built using 6.0" rods on a raised ring piston which places the pin into about the center of the oil control ring,
this combination will give me a (1.6:1) rod ratio which almost identical to a 350cid engine which has a (1.62:1) rod ratio.

Short rod motors make torque down low......
Long rod motors rev till the sun goes down....
and the middle of the road does a little of both.....

standard 400 cranks have to use sleeved main bearings since the main journal is a smaller diameter on the 400 crank than the 350 crank.......
so now custom stroker cranks are readily available with a 3.75" stroke that drop right into the 350 main journals and use standard bearing shells.

hope this helps ya....

 

[mud hungry]

Thank you that does help. What would you say the hp/tq would be of a mildly built 383. middle length rods, high 8 to low 9 compression, mild cam, I know that you could come up with endless variations to the hp/tq but i am just looking for mildly built. Thanks for the info.

 

[4X4HIGH]

standard 400 cranks have to use sleeved main bearings since the main journal is a smaller diameter on the 400 crank than the 350 crank.......

You have it backwards, a 400 crank has mains that are .200" larger in diameter than a 350 thats why if you use a factory 400 crank the mains have to be machined down .200" to fit into the 350 block, if you put a 350 crank into a 400 block to make a 377 then you need bearing spacers for it to work.

 

[4X4HIGH]

What would you say the hp/tq would be of a mildly built 383

There is no given numbers since there are so many variables. Depends on if you use a flat tappet hydraulic cam, flat tappet hydraulic roller cam, solid cam, or solid roller cam. Also highly depends on what kind of heads you use and whats been done to them but with the correct combination you can easily build a 400hp/500ft. lb. engine that is still very streetable and dependable.

 

[Grieby54]

the 400 Hp and 500 ft. lbs. isn't a very mild 383... a mild 383 you'll probably be looking at about 325 -350 hp and 400-425 ft. lbs. But I figure... why go mild, when for just a little bit more, you could go wild? Even with a pretty wild 383 it'll be very a dependable engine and can be used as a DD. Mine's pretty wild... but not full blown racing stuff. I've seen 383's out there that have been build close to 1k hp and ft. lbs... but then again... those engines run you 10k

 

[SUBFAN]

Doubting 4X4HIGH....

 

[icer97]

the 400 Hp and 500 ft. lbs. isn't a very mild 383... a mild 383 you'll probably be looking at about 325 -350 hp and 400-425 ft. lbs.

You are right! Im running 13 to 1 compression, solid cam and big valve heads to make 451 horse. And trust me, its not very streetable.

 

[Grieby54]

muahaha... 10:1 CR and 425 hp 475 ft. lbs.!!! nice and streetable

 

[icer97]

muahaha... 10:1 CR and 425 hp 475 ft. lbs.!!! nice and streetable

Are these actual real world dyno results, or just a guess? Its hard to make that kind of power out of a 383 on pump gas. If so you have a real good combination there that I wouldnt share with anyone!

 

[Grieby54]

actually CR is closer to 9.8:1... and I'd be happy to share the combo with a fellow wheeler!

 

[4X4HIGH]

I personally have built myself a 383 that made 365hp @ 4500 rpm and 509 ft. lbs. torque @ 2000 rpm. I can give anyone who wants it very specific details. Just PM me.

PS. These are real world numbers on an engine dyno.

 

[icer97]

actually CR is closer to 9.8:1... and I'd be happy to share the combo with a fellow wheeler!

Ill share mine too if someone wants them. But I think yours would be more practical.....not to mention alot cheaper on fuel!

 

[Mad-Dog]

Thanx...my bad...!

There is so much to remember and i screw up sometimes...

 

[mtn. burb]

Here comes the desk top dyno war!