Im planning on rebuilding a 400 Chevy it'll prolly be a daily driver on the highway with a th-350 tranny. really what im looking for is about 350-400 hp nothing more or less really. on somewhat of a budget. i wanna retain the stock bottom end and use arp wave loc bolts it prolly wont see past 6000 rpms. but i wanna know what type of heads pistons and cams you guys would reccomend for this buildup. in a way i dont wanna run a really radical cam cuz i dont want to get into radical stall speeds i sorta wanna keep rpms down. i was thinkin world s/r torquer 76cc heads and and like a 214 in duration @50 cam with a decent piston i need about 9:5 to 1 to avoid detonation on pump gas. and what type of head piston combo will i need to get this compression all help appreciated

 

I'd say, bigger cam. Something more like in the high 220's for duration at .050", and lift in the high 400's. Like 480, 490.
A cam that size in a 400 won't need to be revved. We're talking about good torque from 1500 to 5000+.
I'd also recommend smaller sized combustion chambers, and flat top pistons.
I'd agree with the 9.5:1 compression ratio, but don't do it with big heads and piston domes.

 

I agree with NTChrist, some 72cc iron eagles with a set of 12cc dish pistons such as speed pro's H601P will give you around 9.4:1. I would also step up the cam to the 218-225 @.050 and .460-.490 range.

Lonnie

 

"some 72cc iron eagles with a set of 12cc dish pistons"

In that case you DON'T agree with NTChrist.

I'd stick with a 64cc chamber and some flat top pistons. Can run 87 gas just fine.

 

flat tops, 64cc iron heads and 87 pump gas on a 400 is a recipe for disaster and not something i would recommend to anyone.

Lonnie

 

Riiiiiight.... I guess the fact that this combination runs just fine on my engine w/out ANY detonation means nothing.

 

I would think it would simply be a matter of adjusting the timing to accomodate for 87 octane fuel, wouldn't it?

 

Your cr on a 400 with flat tops and 64cc heads can range anywhere from 10.21:1 to 11.65:1 or more.
It will depend on the deck clearance of *your assembled motor*
the actuall cc vol of your valve reliefs (they commonly range from 5cc's to 7+ cc's), Your gasket vol.

9.5:1 is a good target for a mild street motor with the cam you have in mind. You'll be able to cruise on 87 octane if you take it easy., But WOT probabily will need a little more octane 91/93.

Alumium heads will tolerate some more cr. That is why Oddessy is able to get away with it with his big drag cam, converter high gear ratio etc..( around town cruising) I'll bet money he don't race on 87 octane though.

Keith Black racing pistons' has a good online compression calculator for ya. For a budget/ performace 400 with flat tops I'd
get some 76 cc #441 or #487 or #920 or #993 castings and remove a few cc's from the combustion chamber (deshroud valves, clean up chambers) I'd also give 'em a little pocket port job.
78cc finished for a cr of 9.3 to 9.5:1 with a .025" deck height.

http://www.kb-silvolite.com/

 

ah guys to he11 with it just give me any combo with a 406 that pushes 400 hp and runs on pump gas 93 octane max...

 

Well ok:

.030+ 400 5.7 rod Keith Black signature series D cup piston

KB-168 22cc dish pistons
Finished CR is 9.81:1
Chev 5.7" "K" rods w/ARP bolts.
Have the block bored and honed .030 over and "0 decked"
so the pistons come right up dead level with the top of the block
use a 400 cast crank. Get a new replacement 400 balancer and flex plate.
This assembly needs to be balanced.
The rods may need to have the rod bolts ground to clear the cam lobes.

Comp cams 268Xe hyd cam and valvetrain
Chev Vortec heads 1.94x1.50" valves with comp valvetrain
Phone them or consult their catalog
*ALT* Edelbrock assembled E-Tec 170 heads.

Edelbrock Performer rpm Vortec intake
Felpro .041 400 gasket
Edelbrock 750 or Holley 750 cfm vs carb.
1.625" headers/ big exhaust.
This engine will be right at 400 hp or just over.
It will have gobs of torque right off idle.
I'd match it up with a 12" (2200 stall converter) It should be reasonable on gas. And have a reasonable idle and vacuum.

Because of the few little percision details that need attention to build this high perf. street 400, I'd advise enlisting a qualified automotive machinist's assistance , to ensure the success of this build up.
If you have limited experience. It'll be worth it.

www.compcams.com
www.summitracing.com
www.jegs.com
www.kb-silvolite.com
www.edelbrock.com