Hey Guys,

Before Thanksgiving I picked myself up a Vortec 350ci core.

First step is to get it cleaned up and checked for cracks, but I intend to build a nice little stroker motor for my truck.






This block is the short cylinder 880 block that people claim to have issues building a stroker out of, yet GMPP uses this block for their own stroker crate engines. To be on the safe side I'm going to use 6" rods.

Plans: 4.040" bore, 3.75" stroke, 6" rods. 10.5:1 static compression

Parts list/wish list:

Stroker kit: 13057L040
ARP Main cap Studs: 134-5403
ARP Cylinder head bolts: 134-3701
Oil pan: Moroso 20205
Oil pump & tube: Moroso 22124
Cam bearings: Dura-Bond CHP-8
Lunati Voodoo Camshaft: 60112 -231/239 dur @.050"-.535"/.550" lift LSA/ICL: 110/106
Oil pan Gasket: OS34500R
Rear Main Seal: BS40656
Head Gaskets: Z1010: 4.166" x .039"
Starter: SUM-829100
Mighty Demon 750cfm annular boosters: 5402020GC

I will transfer over my currently being used:

Comp 'R' roller lifters
Comp hardened pushrods
Comp 1.52 roller tip rockers
Patriot 'Vortec' heads, 2.02"/1.6" 185cc Int runner, w/ Comp 26918 springs
Professional Products single plane intake
Cloyes double roller timing set (with 880 block grinding)
Spectre aluminum valve covers
Vortec plastic timing cover & crank position reluctor wheel.

The block will get bored .040" over (matching pistons), line honed with the 2 bolt caps & arp studs, decked enough to make true. The rotating assembly will be internally zero balanced.

It'll physically look like my 357ci:





unfortunately, it looks like this right now:



Like my work bench?

With the Lunati Voodoo 60112, @ 1200ft elevation, this engine should have 195PSI cranking pressure & 9.4:1 dynamic compression.

Desktop Dyno estimates output @ 502ft-lbs @ 4500rpm & 463HP @ 5500rpm. DD is usually a little over rated on their power outputs, but should make for a fun little daily driven street machine.

If I get a chance I might swap out my 2800-3200rpm stall converter for a 2500-2800rpm. Even with my current 357ci, the 3200 is just too loose.

On a side note, I'll be taking my truck down the drag strip for the first time. I'm gonna go down the track in full street dress, 22"s and all. Just for fun, I'm not expecting big numbers.I'd be happy with high 13's

Cheers ~Mykk

 

Looks like your going to have a nasty little motor on your hands. Good luck. Do you have any pictures of the truck?

 

 

Thats a nice truck. I'm just a little confused about the engine, you got a old style small block in there right?

 

Wow man nice truck. Im a big fan of the full size chevy. Good luck and ill be watching.

 

Way old style SBC in there...

 

Why 0.040" over?

 

Why would you use a 4.166" gasket on a 4.040 bore?
Just making problems with quench
Why are you changing the factory ext balance to internal?
Limits your choices in flexplates

 

Because I'm partial to .040" over

The 4.166" bore was the just the first SBC head gasket I saw, another search on summit shows a HG to be a bore of 4.080" to be the closest match... other wise they are 4.166" or 4.2"

The rotating assembly is an internal balance from Eagle, you're right that flexplates will be tougher to find.

 

4.1XX are 400ci gaskets

Plenty of 4.060 for 350 available
http://www.summitracing.com/search/P...rd=head+gasket

 

What ya gonna do with the old vortecs?

 

They are currently up for auction on EBay

http://cgi.ebay.com/ebaymotors/ws/eB...=tab%3DSelling

 

Why???

 

I always bore ALL my engins to .040 too. Seems like they are just smoother to me. After I done one and it was so smooth I have always stuck with it. I am currently building a stroker .040 over for my 87 iroc tpi motor. Im going to use a xfi 576/570 cam. What was this you were talking about having trouble making certin blocks strokers? Mine is the stock 87 camaro tpi block. The heads didnt have the casting shape like the one you showed a pic of. So I hope that my block is a good canidate for a stroker. Let me know Mykk Im intrested in this. Plus I like your choice in bore size and motors lol...

 

I'm not trying to condemn your decision to punch it .040", but you really shouldn't bore it at all unless it is necessary. Most of the time a hone will be sufficient.

If you bore it .040" now, and score a cylinder later then you will most likely need a sleeve put in it. The extra 8 cubic inches your going to get from the .040" probably won't give you that much performance gain, especially since your not planning on using it for any kind of competition. You'd find more performance gain by ditching the big rims and putting some drag radials on it, although it would be more money.

 

Your in the clear, the 86-95 blocks are fine. That's the same block I'm using now on my 357ci.

The supposed issue comes from stroking a 96+ truck 350ci.

 

How did you arrive at those figures? 10.5 static with that cam i would not expect to see 9.4 dynamic. Is this thing going to run on pump gas with that compression and iron heads?

DD is not all that accurate but I would expect mid higher 400 hp on motor thats for sure

 

The rotating assembly advertises 10.5:1 static with 64cc heads, I won't know for sure the exact static untill I have all the components and block machining.

My 357ci was supposed to be 9.5scr, when I got the block I used someone already decked it and my SCR is 10.3... later, when I added a bigger cam & heads I used a thinner head gasket and bumped SCR to 10.7

As for cranking pressure & dynamic CR:

http://www.wallaceracing.com/dynamic-cr.php

The greatest factor for DCR is intake valve close degree. The Lunati 60112 has a IVC of 41.5 degree. The longer rods also slightly decreases cranking pressure & DCR.

 

No problems with my '99 Vortec block , minimal grinding required to fit Scat stroker crank

 

Use your seat to seat timing (advertised). When I use my .050" numbers, I get 9.77 which is not right. Other calcs that used .050" timing I got 8.3.
When using seat to seat numbers on this Wallace one, it gives me the correct 8.33 to 1 dynamic.

At my altitude it says 8.09 so it drops abit


Your cam closes at 41.5 at .050. My cam closed at 43 so your probably near 8.4 to 1 dynamic at sea level if using 11 to 1 compression. Using 10.5 to 1 static, you are closer to 8 I would think.

 

I have found Kelleys to be the most accurate.
Download and install
http://cochise.uia.net/pkelley2/dcrvb6.zip

Does CR , DCR and cam timing/ overlap in the one calc

 

I played around with Kelleys calc...

It appears they are coming up with the DCR ratio by using the advertised duration numbers and advertised intake valve close degree. That makes no sense to me. Wouldn't you need to use the .050" IVC degree to get accurate DCR?

But admittedly I need to go back and do some calculations because Comp cams uses advertised duration for cam timing events while lunati uses .050" duration for cam timing events....

 

http://cochise.uia.net/pkelley2/DynamicCR.html

Kelleys again but the formulas are right there. I used this to find my effective stroke and then used a compression calculator with that dynamic stroke to get final ratio. It does use advertised which is what comp cams usually gives you, but my comp cam card gave .050 figures and i calculated the advertised from there

 

Need to use Seat to Seat as already suggested. It was explained to me because camshafts are not all the same at .050 where at seat to seat...its more of a true calculation.

If you use forged pistons, you will actually have a .045 bore because they give .005 for the forged piston to expanded which is why you start up a forged piston engine, you get a little bit of piston slap and then it goes away.

With that camshaft, I would suspect that you need about 10.25:1 SCR to keep your DCR in check between 8-8.5:1 with they nitrous you look like you are planning to run.

 

Because compression doesn't start until the valve is on ( or very close to ) the seat .@0.050 you have no effective compression

0.050 is used when judging cam duration because they say there is no meaningful flow below that figure; but at 0.050 Lift the cyl is not sealed

 

I thought the .050" was a rough generic distance used by hydraulic lifters