[steve]

i was reading that other thread about flow and was wondering if you guiys would comment on mine ? what sorta cam would these suggest to you ? what cams should i stay away from with these numbers ?


Combustion chamber = 93cc

Intake valve - 2.180" 5/16" stem Severe Duty
Exhaust valve - 1.710" 5/16" stem Severe Duty

Depression - 28" H2O

Intake
-----------
.050" 28
.100" 70
.150" 103
.200" 151
.300" 217
.400" 270
.500" 303
.600" 312
.700" 318
.800" 323
-----------
Exhaust
-----------
.050" 28
.100" 60
.150" 88
.200" 131
.300" 180
.400" 221
.500" 249
.600" 254
.700" 260
.800" 262

[steve25]

Well I would not run more than .700" to .730" lift as the head is done at .700" so it does not pay to stress the valve train with more lift, but to get max power from that amount of flow you will want to crank the intake valve open fast with a agressive cam lobe. also your over all exhaust to intake ratio from .100" to .700" lift is a good 82% so a duel pattern cam is probibly not needed if the motor is not turbo or super charged.

[steve]

thanks steve25 ! i guess i have some room to grow with these. no supercharger in the near future !

[steve25]

You did not state what head this was but a 2.18" intake valve can support over 340 CFM@ 28" if the rest of the port can handle a inlargement to the needed port area tand short turn hieght to support the HP that 340 CFM can produce.

[steve]

these are Eheads that were originally ported for a supercharger so you are dead on. idid not have them ported for my specific application so i am glad to hear they will work for me!

[Steve C.]

Those heads have somewhat similar flow as the set of 87cc Edelbrock castings on my previous 462 street motor now retired. They have 2.150 & 1.770 valves and about a 227 intake runer volume. The combo only had 9.7 compression and with a Performer RPM intake, HP950 carb and used in conjunction with a 254/254 at .050 XE solid street roller with .622 gross lift (108 LS/104ICL) it made 580 hp at 5800 rpm on the dyno.

(race weight about 3750 lbs / 10.88 at 127 mph / TH400 w/3.73 gears)

My numbers:
.100 83
.200 151
.300 220
.400 276
.500 301
.600 313
.700 317

The exhaust-to-intake flow ratio was above 80 percent

[steve]

Originally Posted by Steve C.

Those heads have somewhat similar flow as the set of 87cc Edelbrock castings on my previous 462 street motor now retired. They have 2.150 & 1.770 valves and about a 227 intake runer volume. The combo only had 9.7 compression and with a Performer RPM intake, HP950 carb and used in conjunction with a 254/254 at .050 XE solid street roller with .622 gross lift (108 LS/104ICL) it made 580 hp at 5800 rpm on the dyno.

(race weight about 3750 lbs / 10.88 at 127 mph / TH400 w/3.73 gears)

My numbers:
.100 83
.200 151
.300 220
.400 276
.500 301
.600 313
.700 317

The exhaust-to-intake flow ratio was above 80 percent

were they more than 87 after porting ? mine will also be around 9.7:1. No doubt my
cam is smaller as Dave at SD recommended capping the HP at just over 500 because
of my "557" block casting. i plan to beat up that 557 and then eventually get a bullet proof shortblock. I would have thought that guys in the pontiac community would cheer me on hoping that the block survives.....all i get is grief.

[Steve C.]

After the chamber clean-up and valves installed mine are about 90 cc's.

[1971WARBIRD]

Originally Posted by steve

I would have thought that guys in the pontiac community would cheer me on hoping that the block survives.....all i get is grief.

i'm not going to give you grief, but wish you luck.better blocks are out there for little to nothing that is why i wouldn't build a high power 557 combo.i built one that should be pushing high 300's for a 78 body i had(have engine still sold body)but it is just a fun street engine.i ended up throwing away 2 blocks,a 577 and a 73 400 that i didn't have room for any more and no one would come and get them so they went to the scrap yard.the most i've paid for a 400 block is 100 and that is because i wanted a certain date code.

[steve]

Originally Posted by 1971WARBIRD

i'm not going to give you grief, but wish you luck.better blocks are out there for little to nothing that is why i wouldn't build a high power 557 combo.i built one that should be pushing high 300's for a 78 body i had(have engine still sold body)but it is just a fun street engine.i ended up throwing away 2 blocks,a 577 and a 73 400 that i didn't have room for any more and no one would come and get them so they went to the scrap yard.the most i've paid for a 400 block is 100 and that is because i wanted a certain date code.

thanks ! gotta love the love ! i just need a little understanding. i read threads and have done a little research and it seems like guys pay anywhere from 6000-14000 for a 500+ HP poncho done right. I will be done at well under 6K on this deal (you gotta consider what i had and what i traded for) when done.

100.00 for the block but how much for a stroker shortblock all machined and assembled ? how much for new Eheads that have been pro ported ?

realistically there isnt much possiblity of me putting that power to the ground for quite some time (after all the suspension upgrades, rear, tranny ect). so i plan to have fun with that 557 until it pops or i am ready for stouter block. at that point all my other go fast goodies should still work !

SO, say a prayer to the poncho gods and we will all get to learn something as i progress with my 557 build ! who knows maybe there will be a rush on those "special" lightweight 557 blocks everyone has been passing up ! maybe i will beat the poop outta it and it will live. wouldnt that be something ? dont be a hater...this should be fun Y'all !

[steve25]

One option you might concider would be to add splayed main caps to your 557 block.
It will cost some money but they could then be re-installed latter on in a different stronger/earlyer block down the road with just another line hone job, so you would be spending some more money now to save money latter!
This mod in and of itself will keep that 557 block togetheir for as long as need be as long as your tune keeps you out of detonation, which will take out any motor with no regard for how strong it is built.
I would also spend time if you do the main cap thing or not to very well deburr and chamfer all the sharp edges over on the inside of the block. Pay close attention to the top of the main cap holes and the oil feed holes in the main saddles, as this is where most of the block splitting/cracks start in the 557 block.
The other spot is the top of the main cap dowl pin hole, but to radious that over you will need to take the block to a shop and have those pins pulled.
Also do not chamfer over the parting line of the bearings in the blocks main jurnals
or you will loose the needed bearing crush that holds the bearings in place, and besides I have never seen cracks originate from the parting line on blocks that have failed.
Dont forget that if your 557 block lets go at any thing more than a idle you will loose most everything and then have to fund the cost and deal with the time of starting from square one.

[steve25]

Sorry that should have siad"top of the main capbolt holes".

[steve]

steve25,

thanks man you are being very helpful. the block is already put together and i am not spending a nickle more on it. i bought it that way and was told attention was paid to the detail but like others have said...it might not matter anyway. with 92cc chambers on the e-heads i will be well under 9.7cr so that should help eliminate detonation. i plan to watch oil pressure like a hawk. any weirdness will get closer inspection.....

my last motor died due to detonation (at leat i assume that did it). dont want that happening again !