janbanan24

Hoping to get some well needed help from this great forum:

I'm rebuilding a 4-bolted 350 with a cast 400 crank and 4.040 bore.

I was looking at maybe the Holley SysteMAX II or some other "top end kit" since I don't have the know how to hand pick the peices my self.

But maybe someone out there can help?

I'm not sure what info I should give to get correct help though...

But I could try:

So as you can see I have not planned to have a very high compression ratio or to be revving the engine like crazy for maximum hp.
The car will not be a daily driver and I kinda like the sound of bad "racy" idling!
...The goal however is to have the torque pretty early in the rev-register and as much hp as possible without going above maybe 5500rpm?

Little Mouse!?



...anyone?

andylmusic76

i'm pretty sure someone will recommend brodix heads to you. i don't know to much about them, but they have a high reputation to speak for them! i also hear good things about aluminum heads; although, personally i would just use cast as you can't really strip the threads, they won't warp like aluminum, and the weight won't make too much difference unless you're setting it up for racing only. when i was building my engine i was discouraged to use aluminum, so i stuck with cast. i am very pleased with my results though.

rclinton

Im getting ready to start building my L82 stroker. Im sure there will be many opinions, For my build, the ball park components I looked for were 64cc cc 195cc runner aluminum heads, 9.7 cr, Lunati voodoo cam .499/.521 lift 219/227 duration with 1.6:1 roller rockers, professional products cyclone intake, with a Lars rebuilt Edelbrock Q-jet, exiting through a set of hooker sidepipe headers. DD 464/491 numbers, will be happy with a 400/400 result. Power made all below 6000 RPM so Im looking forward to a fun street weekend driver. Good luck on your build.

hammyjoe

I felt the same way when I started my rebuild and found all of my answers in this forum. Just finished the rebuild. Used a 4 bolt 383 shortblock bored .40 w/flattop pistons, and cast crank. For the top-end: aluminium vortec heads, magnum 280 cam, rpm airgap intake, 600 cfm edelbrock carb. Still tuning the carb, but am really happy with the outcome. No clearance issues with the hood and gobbs of power. Good luck with yours.

column5

No clearance problems with the air gap? I was at Comp Cams yesterday talking with a guy about their cams and RHS heads. He reccomended the RPM air gap but I was concerned about clearance on my 74.

hammyjoe

I read the fine print after I had already bought the manifold and I'm not sure if having no hood liner helps with the clearance or not. (It's been a long and fun project)

Before I started my project I was looking at the same top-end kits, but had read in this forum that to make the advertised hp your rpm's are up around 6000 or more. I'm not comfortable spinning my shortblock that high. Cast crank and all. For me, learning about the different components and building it was 90% of the fun.

VIPERBARON

If you are using the stock rods, then the dish pistons will give you lower compression ratio.
Stock 350 rods are 5.56 inches long and the stock crank has a stroke of 3.48 inches.
Cast crank? Why oh why? Find a good forged 4340, internally balanced crank. Forged rods are a plus as is forged pistons.
While you are at it, just go to a 383 stroker.

janbanan24

Ok, thanks for all the input and cheering on!

Am I wrong to assume that modern aluminium heads are better than old iron heads in most every way?
Should be better engineered combustion cambers and runners, less warping/heat collecting and should move the center of gravity down and back a little if Im not misstaken?

And one other thing: crank and rods are "original type" cast iron from a 400 so yes it was a 383 stroker while it was 030 bore (when I bought it) ...now 040 bore, should make it a 385 stroker or something like that?

So how would it be with this set up you think?
Heads: Trick Flow 195, CNC, 64cc
Intake: Performer RPM
Cam: Comp Cams 12-246-3 (Hyudral)
Rocker ratio: 1.6

...but then I think I would have to modify the hood!?

VIPERBARON

Yup, 3.75 inch stroke, 5.7 inch rods with 4.040 pistons will give you a wolloping 385.
Alum heads disapate heat better than iron, so you can run a tad higher compression ratio. Weight savings too as alum heads weigh in at 25 pounds and iron hit better than 70 pounds. Each.

jackson

400: rods are 5.565", stroke 3.75", bore 4.125"

350: rods are 5.7", stroke 3.48", bore 4"

Jan? You are running short 400 rods right? What is Part Number of your KB d-cups? Is it KB142 with -18cc dish?

Has your block been decked? If so, how much?

if stock deck, & KB142 & 3.75" stroke ... get a 64 or 62cc head ... 62cc & GM 10105117 gasket (0.028" x 5.8cc) would be pretty good. Better would be deck block to remove about 0.012"-0.014", KB142, same GM gasket but 64cc heads ... that'll get your quench in the ~ 0.040" range w/ about 9.6:1 scr.

janbanan24

Sorry, maybe I was not very clear about this, lets try again:
Rods are 5.7
Stroke 3.75
Pistons KB197
Block is decked, but I really don't know how much!:o

Thanks again for your help!

V77Vette

i may be wrong but i thought a 400 had different size mains than a 350
unless thats what you mean when you said you had the crank machined
or its a 350 mains 400 crank? (i see now where you said it was a 383 stroker so thats prob what you have)


sorry my bad i just seen where you said original type crank and thought an original 400 crank wouldnt fit in a 350 block

janbanan24

Yeah, I think the 400 has different size mains. (If that's what you would call the cranc bearring areas? I'm from Sweden you know so English is not my first language! )
...so the "mains" were probably machined before the crank would fit in the 350 block, and are now machined again because they were worn from bad lubrication.
I guess it was pretty missleading to say "400 crank and rods" when I actually ment: 383 stroker with cast iron crank and rods, where ever the parts came from.

SO! I have a colegues friend who is bringing over a container from US to Sweden with a car and I can let my future cam, heads, intake manifold and stuff like that ride along in the boot, help me out here, again:o , what would make sense to buy to make a torque-monster out of this 385 stroker?

BTW you can see some pictures in this 16-page-thread in a Swedish Corvetteforum about my Florida salvage:
http://www.clubcorvette.se/forum/vie...er=asc&start=0

jackson

KB197 has -12cc dish and 1.433" CD. Find out. You need to know how much your block's been decked so you can choose correct gasket & head. If ... IF your block had NOT been decked ... KB197 and 10105117 gasket & 64cc heads will yield about 10.1:1 scr w/ 0.045" quench.
If ... IF same stuff but your block decked 0.006" ... it'll yield about 10.2:1 scr w/ 0.039" quench.

If you want scr about 9.6:1 you should consider a 70cc head.

janbanan24

Ok, I see!

So how do I "find out"?

Can I control it by checking that the deck is flat and then install one piston and measure from tdc?

...or is there a quicker way?

jackson

Yes ... that is how you do the job.

Check four cylinders 1, 7, 2 & 8. You can use same piston-rod ... move it from 1 to 7 to 2 to 8. At each cylinder, measure how far piston is "down in hole" ... measure around each hole at 4 places 0, 90, 180 & 270 ... then average those to average how far down in hole. Measure from deck to piston's flat area of crown near outer diameter of piston ... notice at extreme outer edge of piston there is a chamfer ... do not measure from deck to chamfer ... measure from deck to just inside chamfer. Dunno how much your block decked ... but in a STOCK UNCUT block that piston should be about 0.017" down in hole. Expect yours to be something less than 0.017".

Acquire accurate, precise numbers and post back here at this thread.

janbanan24

When I don't have the cam yet, how do i determine tdc?

Should I just try to see when the piston is as high up as possible and put a steel ruler over the deck and measure with (don't know the english word... thin steel leafs?)
...or should I mount a "indicator clock" to the deck to se the absolute tdc?

Capella

Yes.

69camfrk

Cast crank is no problem as long as you're not putting a severe shock on it ie: drag slicks. If the reciprocating assembly is balanced on a 350 going past 6 grand isn't an issue. I am using the Holley systemax set up on my '69 Camaro on a 350. I spin past 6 grand pretty much everytime I drive the car. My crank is cast but the assy is balanced. I'm going to do a 383 for my "new" '72 but the motor will be all forged stuff on this one. I'm planning on using the Brodix head package as it is only a few hunderd dollars more than the Holley. No cam with it, but most everything else.

janbanan24

So, now I know that I have a 4-bolted 350 block, 400-cranc, 350-rods and KB-hyper pistons -12cc.
The block has not been decked so the distance from deck to piston is appr. 0.0059, bore is .040 and I also have a "Victor Reinz SB Chevy 350 Performance Gasket Set", but I don't know the thickness of head gaskets yet.

Any ideas?