Hot Rod Forum banner

Getting to around 396cid using 880 block

16K views 27 replies 4 participants last post by  Hogg 
#1 ·
To expand on my other thread about using a 400SBC with a roller cam in an L31 Vortec 350 application.


What is the best way to get to around 396 cubic inches in a GEN 1 SBC? Anyone know of any good kits, or is this a more of a select individual parts type of project?


The engine will be used in a 4000lb performance truck application. In this truck, I have to use this 4x reluctor wheel.


And the front timing cover on the left.


Fueling wont be an issue as I am using a marine MPFI intake manifold which allows conventional injectors to be used .


instead of the CSFI poppets(top of this pic)



Truck will see lots of street/strip duty. Quality higher stall torque converter will be used. 4L65e will probably be used, possible 4l80e.
28" tire.
Overall acceleration will be the focus with this truck.
Vortec hread bolt pattern will be used. Production Vortec, AFR Vortec, ETC 170 or 200, GMPP 210 Fastburn, or GMPP Small 180cc port or Large 225cc port Bowtie Vortecs are head options. Any input on heads?

thanks

peace
Hog
 
See less See more
4
This post has been deleted
#5 · (Edited)
I am aware of that intake, the intake I am using is a direct replacement for the stock truck intake, and mcuh better than said stock intake. I have it, its installed and works MUCH better.

The Scorpion tunnel ram you are talking about sold out just a few months ago. New units were for sale very inexpensively by Edelbrock as leftovers from Merc tunnelram production, but I would still need to fab an upper plenum as the stock Scorpion plenum isnt suitable, unless it can be rotated 180º.

The cross ram MPFI Merc intake I pictured was used on the 300-330hp 6.2' engines, the tunne ram you speak of was used on the 330-400 hp Scorpion engines.

Scorpion lower tunnelram, different marine upper with progressive marine t-body


Same intake installed



Here is an Indmar non-Vortec intake Its on ebay right now




I dont knop how they run the ignition as there is no distributor hole.

peace
Hog
 
#3 ·
you'd be best off forgetting the stupid vortec bolt pattern requirement and using one of the standard intake available.
why that rule?

a 3.875" stroke can be made to work, just be careful on rod selection.

Honestly it won't have much advantage over a 383, and be a little more prone to wear issues.
 
This post has been deleted
#7 · (Edited)
Sounds like staying at 383 cubes and optimizing the package would be best. This isnt an all out race engine, just a fun street/strip machine economy and driveabilty concerns are minmal

Headers 1 5/8 x 2.5" collectors into dual 2 1/2" exhaust that crosses over to the passenger side into dual 2 1/2" cats then exits out the pass. side via dual 4" pipes.

I have full PCM tuning ability. I am running 25 lb/hr(at 3 BAR-43.5psi) stainless steel Multec 2/EV6 injectors which flow 28.8 lb/hr(4BAR=58psi).

It just seems as though lots of people do 383's and few of them run as I feel they should.
There was a guy who did a Vortec headed 383 with GM LT4 hotcam kit, stock L31 truck intake and fuel system and he dynoed 330rwhp/381rwtq with home ported L31 heads and headers and a 3000rpm Vigilante TC. He got his extended cab 2wd 98 truck into the mid 13's.
His truck is one of the few 383's that runs decently.

I dont feel the GM HT383(340hp@4500rpm/435 lb/ft@4000rpm with cam 196º/206º lift of 0.431"/.451" LSA 109º is worth the money12499101=$4759.
Or the HT383-E 17800393 crate which is an HT383, minus teh carb intake, plus new distributer, L31 spec balancer, new wires and plugs. Cost is $5199.
The 4340 crank in them certainly doesnt look pretty and its the same exact longblock that they use in the ZZ383,- p/n 12498772-$5459- 425hp@5400rpm/449 lb/ft@5400rpm with the 222º/230º .509/.528"lift 112ºLSA.
GMPP states that deviating from the specific intake they use on the ZZ383 can reduce power by 20hp. Makes sense.

This is starting to seem like a nice 6.0 LQ4 with a cam and headers would be more economical. I would like to stay with the GEN 1/1E family, I dont know why, nostalgia maybe???

Decisions decisions.

peace
Hog
 
#12 ·
I think read something about that. The 880 block is what a lot of the GMPP crate engines are buit off of, including the ZZ383/HT383/HT383-E. Before the 880 block, the 638 block was used. The 638 block was used on some early GM 383 engines.

Casting numbers:
10243880 = 95-00 Vortec truck, 2- or 4-bolt mains, roller cam, one-piece rear seal. All have full provisions for factory roller cam: thrust plate and lifter retainers bosses tapped.

14093638-was an 87-95 HD 350 block

Apparently the 638 block has roughly an extra 1/2" of cylinder bore at the bottom of the bore compared to the 880 block. There are pictures, but the links have expired.

The GM 383's use the 4340 forged steel cranks with a 3.80" stroke. I wonder if you could offset that gring that crank?

I have seen a few of those cranks and they havent looked pretty. When the counterweights were drilled ofr balancing some of the holes werent even in the middle of the counterweight, the outside of a few of the holes actually opened up through the side of the counterweights. Just sloppy work.

It costs $1150 12489436, and is to be used with the GMPP 4.005" hyper pistons 88962748-$294 or 0.030" pistons 88962749-$289
5.7" PM rods-GM rated for 550hp-clearanced for cam for 383 use-19169670 $450.

Appears as though this crank is internally balanced as well.

peace
Hog
 
#13 ·
You're really over thinking a combo that has been done to death, just get a good block with a good bore and go with the standard 3.75" strokje, 6" rods, pistons of your choice, and assemble.

your piston and ring choice will make more of a difference than .050" of stroke.
 
This post has been deleted
#14 ·
I didnt realize that the marine folks used GEN II engines, that would explain the intake then. That also explains a few other marine setups that I have seen as well.

On a 383 would you go Vortec Bowtie smallport. Fastburn alum., or Vortec Bowtie largeport.
You say that the Fastburns would require porting to equal the largeport heads flow numbers. Is a 383 going to require such flow numbers. Making big torque and power numbers is one thing, but at what rpm will this be happening?
I might as well ask for roller cam recommendations as well. Input?

I have talked to guys who have installed FAstburn heads on 350's and used the Fastburn 383's 222º/230º cam and found it to be a revvy cam lacking low rpm torque.
Another guy had a couple valve seats fall out of a set of Fastburn heads.

I recently read an article where they took an HT383, added a different roller cam and came up with 460hp, up from the 340hp rating. IIRC the cam was in the 230º-240º range at 0.050".This was promising and has me wondering if I really even need to look at other heads???

peace
Hog
 
#16 ·
383-388 cubes, peak power 5500-6000, redline 6500 Intake can be changed in future.

Truck runs 4.10 gears with 27" tire, 2800converter(will be changed)

Supercharger no thanks, I dont want more things driven off the crank, way too many L31 have snapped the cranksnout off more my comfort.

PCM tuning isnt an issue.

peace
Hog
 
#17 ·
If you change your intake now you have a MUCH better head selection.

225cc ports are too large for that power peak, you need a 210cc or so port like the Fastburn heads, which are actually really good heads but they could use a little clean up, which will cost time or money or both.

The fastburns will easily get you around the 450-475hp mark (assuming you find a decent intake) at 6,000 rpm, but if you want to go over 500 you'll need to get them cleaned up.
 
#21 ·
Here's a good set of heads for a 4" bore,
This is my 215cc offering
he also offers these heads,
Pro-Filer ECONO

which are better for a larger bore. Either head is 600+hp capable. For the intake, on a street runner I would run the 7137 Edelbrock intake.

The heads/intake combo would be about 2 grand but then you need injectors, throttle body, fuel rails, etc.

The power comparison compared to a marine intake with fastburn heads isn't even close, BUT you have to invest in a completely new intake manifold system, which isn't cheap.
 
#23 ·
I do like that 7137 intake, I was looking at its Vortec brother in the past, for use with the Largeport Bowtie Vortecs.

Those heads look like they are serious parts. Do you have personal experience with that company? HAve you used these parts?

This is starting to look like a higher rpm setup now.

Any opinions on converting a 2 bolt block to splayed mains, or would stock 4 bolt mains suffice? Would you take 2 bolt mains to 7000rpm?

Thanks again.

peace
Hog
 
This post has been deleted
#22 ·
I dont think anyone mentioned the LT4 hotcam, but I agree I wouldnt use it.

Here is the 294S cam you reccomended
Operating Range: 2500-6500 RPM
Duration Advertised: 294° Intake / 294° Exhaust
Duration @ .050'' Lift: 248° Intake / 248° Exhaust
Valve Lift w/1.5 Rockers: .525'' Intake / .525'' Exhaust
Valve Setting: .022'' Intake / .022'' Exhaust
Lobe Separation Angle: 110°


Looks like it would work well, but I will be staying away from flat tappet cams.
Anything similar in hyd. roller?

There are some 880 blocks floating around with 4 bolt mains on the 3 center mains.

thanks for the Scat kit info, I like the sounds of getting a kit that has been balanced with the damper and flexplate as a whole.

peace
Hog
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top