400 in the 68 Chevy

[Bobby277]

here is that other flywheel. $83.99

http://www.jegs.com/i/JEGS/555/60125...RloaAudj8P8HAQ

[Captainfab]

Yes the flywheel at Jegs for $84.00 will work. But be aware that both the flywheel at O'Reilly's and the one at Jegs are most likely made overseas. Personally I would rather have a GM flywheel that has been re-balanced for a SB 400, or a high quality aftermarket flywheel. But for most purposes either of those flywheels will work.

[Bobby277]

I think I've got my rotating assembly all figured out guys, thanks for all the help! It makes a world of difference!

My last important question (as of now) is cam choice. I want a mild, tourqe cam. I don't have the slightest clue on how to pick a cam, can I get some suggestions?

[68post]

Originally Posted by Bobby277

I think I've got my rotating assembly all figured out guys, thanks for all the help! It makes a world of difference!

My last important question (as of now) is cam choice. I want a mild, tourqe cam. I don't have the slightest clue on how to pick a cam, can I get some suggestions?

Still stock compression and heads ? Stock valve springs ?

[DBD]

probably isn't a quicker way to start a fight than ask what cam to use

need to decide if you want to spend $600+ to go to a roller...not worth it for this build...

lift - around .450-.460 if you're staying with stock vortecs.

good street manners come from valve timing...for what you want a mild cam with a fair bit of advance is a good pick - I like the CompCams Xtreme Energy 4x4 stuff for cams that work really well in a relatively light truck with a warm engine. I've used the 12-235-2 a bunch, and it works great with stock vortecs. the stock vortec springs are a little light for that cam...but you won't turn it past about 5200 rpm anyway, and they won't float (promise) at that speed.

Just don't buy a high-rpm HP cam for a low rpm torque engine and use...

[Bobby277]

I certainly don't want any fighting! Lol just input!

So this is where I am

http://m.summitracing.com/parts/fem-mhp138-000

That's the kit that's going into the 400, and I might run that with stock heads JUST for a bit, then it will most likely get vortec heads with a performer intake and some thicker head gaskets with new head bolts. I now have summits compression calculater bookmarked BTW! Pretty handy little deal. The summit kit is first though

So that's where I stand 68post.

[68post]

ERSE110020K
specs>> 275/278 209/216 .435/.455 112 $122.00

Erson Cams / PBM cam and lifter kit.

This would be fine in a stock 400 with stock heads, has old school ramps to be easy on the lobes 'n lifters and could lead a long life with proper break-in & decent oil.

[DBD]

that kit is going to put you into 10:1+ with Vortecs - the 12cc difference in chamber size is about 1.1 CR. you can't just use thicker head gaskets to drop the CR...

it looks like they're expecting you to resize the rods, so it's based on the stock rods. the resize will cost about what a set of new SCAT 5.7 rods would cost. Note that all the sizes are standard, too...which they won't be on your build. Just make sure you don't order anything until the machine shop is done with their work. It's also got an HV pump...which I would never use or recommend. Not trying to be a dick...just not a kit I would choose.

no problems with a strong ramp with the right cam lube, break-in and oil...

[68post]

Originally Posted by DBD

no problems with a strong ramp with the right cam lube, break-in and oil...

yes, but you'll always have to use a high zinc/moly oil. I prefer a fast ramp cam too , but as you alluded to .. there are 500 ways to go on a cam !!

That Erson cam would be "on the edge" for 10-1 compression, but more forgiving than the Extreme cam.

(very similar too: 210/218 vs. 209/216, 111 LC vs. 112 LC )

[Bobby277]

Originally Posted by DBD

that kit is going to put you into 10:1+ with Vortecs - the 12cc difference in chamber size is about 1.1 CR. you can't just use thicker head gaskets to drop the CR...

it looks like they're expecting you to resize the rods, so it's based on the stock rods. the resize will cost about what a set of new SCAT 5.7 rods would cost. Note that all the sizes are standard, too...which they won't be on your build. Just make sure you don't order anything until the machine shop is done with their work. It's also got an HV pump...which I would never use or recommend. Not trying to be a dick...just not a kit I would choose.

no problems with a strong ramp with the right cam lube, break-in and oil...

Please elaborate DBD?
Why wouldn't a thicker head gasket drop my Compresdion ratio?
Where are you getting that it expects me to resize my rods?
And why wouldn't you use a high volume oil pump?
Just Curious! Thanks

[Captainfab]

Not to disagree with DBD but I have had good luck with a little bigger cam in a 406. This one:

http://www.summitracing.com/parts/cc...39-3/overview/

You should upgrade the springs and check retainer to seal clearance. The Vortec heads we used did not require any machine work for clearance. There is more info on that build in my thread titled "400/406 Builds"

[DBD]

Originally Posted by Bobby277

Please elaborate DBD?
Why wouldn't a thicker head gasket drop my Compresdion ratio?
Where are you getting that it expects me to resize my rods?
And why wouldn't you use a high volume oil pump?
Just Curious! Thanks

your quench will be terrible with a thick gasket - if you expect to have the pistons .020 or so down in the hole your quench with an .051 gasket would be .071+...around twice what you want. quench is really important on the street because it determines detonation sensitivity and has an impact on power.

imho, these "im going to do this now, and then later I'll do this" builds don't work very well...

if you're reusing your existing rotating assembly then your crank will have to be machined and your rods will be resized - you're already talking with your machine shop, right?

hv pumps steal hp and with tight clearances make for sky-high oil pressure and the pump being in bypass all the time - bad, bad, bad. hv pumps are a leftover from when people were running wide clearances and as a crutch for a worn engine...not for performance use. and most of the stock replacement pumps aren't made for performance use...I only use the melling select performance pumps.

My thinking on vortcs is that if your spending money to upgrade them you should just buy better heads...

[Bobby277]

I think I understand what your saying. Then what would be the ideal "quench" for this engine, saying it had vortec heads? And how thick would I want my head gasket to be?

Also is there any problem with running 10:1 compression? Would I just have to use higher octane fuel?

[DBD]

ALL flat-tappet cams need high zddp oil unless they're very, very mild.

[Bobby277]

According to summits Compression calculator I could have a compression ratio of 9.72 : 1 with this kit and 64cc vortec heads and a .051 in head gasket? If I go that way. Would like to hear what you have to say.
Am liking the responses guys, this turned out to be a helpful thread!

[68post]

Originally Posted by Bobby277

According to summits Compression calculator I could have a compression ratio of 9.72 : 1 with this kit and 64cc vortec heads and a .051 in head gasket? If I go that way. Would like to hear what you have to say.
Am liking the responses guys, this turned out to be a helpful thread!

Your quench distance should be in the vicinity of .041" to .045" , anything wider will likely cause the engine to be octane, and/or timing, sensitive and create a less efficient burn.

Zero decked but with a .051 gasket = a distance of .051 for quench, and that is more than would be ideal.

[DBD]

ideal quench is around .040 - there are a lot of ways to get there. thin head gaskets are expensive, but of course you don't change them so you can leave the pistons .025 down in the hole and use an .015 gasket...or zero-deck the block and use an .040 gasket. I tend not to zero deck on a street build, but there's no wrong answer.

high compression doesn't buy much for the problems it can cause. unless the engine is making a lot of power, 10:1 adds only a few ponies over 9:1...and 10:1 absolutely requires premium gas if the timing curve is set to maximize power.

[Bobby277]

Well cool guys! I think you've answered all my questions for now! I really appreciate all of the replies. You'll probably find me in other threads here and there.