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-   -   stock 400 small block - how much dish? (http://www.hotrodders.com/forum/stock-400-small-block-how-much-dish-121977.html)

Ekki 08-11-2007 06:03 PM

stock 400 small block - how much dish?
 
Hi folks,

I thought about 'reviving' my 400 small block. It's a 511 casting with 997 heads. I would like to leave the bottom end alone for now and only add better heads and a new cam, probably a Comp XE272H. I don't think I'll need the performance of those fancy aluminum heads and that's why I thought about a pair of RHS ProTorker Vortecs (170cc/64cc).
The only reason why I still might consider aluminum is the increased compression - which is a good thing but maybe a tad too much for those iron heads. I know that these 70s 400s have dished pistons but I'm not sure exactly how much. This info is probably somewhere out there but I'm unable to find it.

Thanks for your help.

Ekki

Chevrolet4x4s 08-11-2007 07:27 PM

not sure how much those heads cost but patriot has new aluminum 1.60 2.02 with 64 cc chambers for $795
Shane

Ekki 08-12-2007 04:00 AM

It's interesting that you mentioned these Patriot heads.
I was almost ready to order a pair of their 'Freedom' series when someone else (much more knowledgable than me) told me to stay away from those 'off brand' heads.

Any first hand experiences with these heads?

Ekki

ernkazern 08-12-2007 08:57 AM

Question
 
I imagine you want to know how much dish your pistons have so you'll know what your compression ratio will be with the new heads? If you know what your compression ratio is now and the cc of your present combustion chambers you can make a good educated guess as to where you'll end up with the new heads.

Ekki 08-12-2007 09:50 AM

Quote:

Originally Posted by ernkazern
I imagine you want to know how much dish your pistons have so you'll know what your compression ratio will be with the new heads? If you know what your compression ratio is now and the cc of your present combustion chambers you can make a good educated guess as to where you'll end up with the new heads.

That's correct. As far as I have read the stock heads(76cc)/stock pistons make a compression of appr. 8.5:1. This would appr. mean a 20cc dish.
If this number was correct I wouldn't see a problem with 64cc iron heads since this would give me a compression of appr. 9.5:1.
OTOH I've read somewhere else that the stock engine has appr. 9.0:1 compression - which would produce >10:1 with 64cc. Maybe a bit too much for iron heads.

F-BIRD'88 08-12-2007 03:06 PM

Either the RHS pro torker vortec head or a Upgraded modified GM 062 oem vortec head will work great on your 400. use either the Comp XE274H-10 or the Comp XE284H10 . It will make more power with the larger cam yet still very torky with the vortec type head.. it's not too much.
If you want aluminum, get the 64cc Edebrock E-Tec head. Use a vortec intake manifold. Either way will be a winner. All these heads are better than the Patriot heads. More usable torque thru the majority if the rpm band you'll be using..
If you have the factory type 400 dished piston your cr will not be too high with a 64cc head. If you have flat tops in your 400 use a 72-76cc head.

Chevrolet4x4s 08-12-2007 05:19 PM

Quote:

Originally Posted by Ekki
It's interesting that you mentioned these Patriot heads.
I was almost ready to order a pair of their 'Freedom' series when someone else (much more knowledgable than me) told me to stay away from those 'off brand' heads.

Any first hand experiences with these heads?

Ekki

CarCraft did a test on them recentally with good results.
Shane

MI2600 08-12-2007 06:39 PM

I thought that Car Craft test showed they were not that spectacular compared to the Vortecs.

Chevrolet4x4s 08-12-2007 07:52 PM

they were very close in Hp to modified Vortechs.
Shane

377paul 08-12-2007 09:40 PM

stock small block
 
Are you sure you want to do this? Is the bottom end stock? Depending on which intake manifold, heads, headers, carb CFM, etc., you could make up to 460 HP at 6000 RPM with the XE274H cam. This sounds like shrapnel time to me if you don't go with a good crank, rods and pistons!
Look at some of the 383 engine kits on line to get and idea of the possibilities.

F-BIRD'88 08-12-2007 09:48 PM

Quote:

Originally Posted by 377paul
Are you sure you want to do this? Is the bottom end stock? Depending on which intake manifold, heads, headers, carb CFM, etc., you could make up to 460 HP at 6000 RPM with the XE274H cam. This sounds like shrapnel time to me if you don't go with a good crank, rods and pistons!
Look at some of the 383 engine kits on line to get and idea of the possibilities.

This motor will peak out before 6000rpm. There is no reason to rev it higher.
its not nessess sary to abuse this motor with excessive rpm to make it perform.
5500 to 5800 is all thats nessessary for max performance.

Therefore the stock crank, rods and pistons will be fine. You'd need the XE284h-10 to make 460hp or very close to it. Most likely 450ish hp. You'll have a ton of usable torque. the Xe274 will make a little less all the way thru the band from 3000 up. The Xe284 needs a 11" "2800-3000 stall" converter.

377paul 08-14-2007 12:16 AM

400CID power
 
F-BIRD'88 is right. With ASSUMPTIONS of 1.94"/1.5" valves but H.P. heads, large headers w/o cat, 9.5 C.R., hi flow dual plane intake with 750-800 CFM carb., and the XE274H cam, the numbers are 415 HP @5500 RPM and 460 LB-FT @ 2500RPM. This is doable. Source is Camquest(R).
I still worry about the rotating parts condition. :sweat:

Ekki 08-14-2007 04:49 PM

Thanks a lot for your feedback/suggestions, guys. The bottom end has to wait for now - if the whole mill falls apart I'll use the 350 again which is now in the car. I had bought a XE262H for this motor, besides I have a Hughes 2500 stall converter, a 700R4 transmission and 3.55 gears. I think those heads would also be nice addition to the 350 - if everything else fails...

Btw, resumption of 'project 400' was a rather spontaneous idea cause right now I have an opportunity to ship rather heavy parts (like cylinder heads) over here - which otherwise would cost me more arms and legs than I have. ;)

Ekki


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