BBC steel head comparison

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Schurkey
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Re: BBC steel head comparison

Post by Schurkey » Mon Dec 03, 2018 5:59 pm

travis wrote:
Mon Dec 03, 2018 4:23 pm
Don’t L29’s have a non adjustable valve train too?
Yes, and rotators on both intake and exhaust springs. All of that is fixable.

The ski-jump in the intake port is more difficult.

pdq67
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Re: BBC steel head comparison

Post by pdq67 » Mon Dec 03, 2018 8:00 pm

travis wrote:
Mon Dec 03, 2018 4:23 pm
pdq67 wrote:
Mon Dec 03, 2018 4:09 pm
Charlie,

Mark does a great -236 head, but I don't by any stretch think the intake ports are down around 195 to 200 cc's like stock PP heads vs the L-29's at say 130 to maybe 135 cc's or so IF I have this right, please check me here. Almost all stock large ovals are generally like 155 to may be 160 cc intake port sized..

I might still have OR had a mag article where they compared the new L-29, 454, P/U engines heads to the old 454 PP P/U engines heads and there was no comparison due to the 100 cc heart-shaped, fast-burn chambers of the L-29 head vs the something like 113 cc's or so standard chambered large oval head.

And I am NOT taking anything away from Mark because earlier John L. did a couple of tests (in two different mag articles), years ago using a 496 and later a 502 both starting out as lo-po, reworked PP headed, P/U engines turned Hi-PO with more cam and better reworked heads. One article is in the mag that has, "Chezoom", on the cover! CR stayed the same all through the tests. I want to say like 9.2 or 3 to 1 CR?? I want to say his 1st cam was a CC 252HE(??) for P/U or tow-truck engine use..

I bought my, "swap meet", -206's that should be down around 96.7 to 98 cc chamber size to play with using a stock mid '70's P/U 454 along with just .020" thick steel shim head gaskets to try to up their TERRIBLE about 7.9 to 8 to 1 CR so that a decent cam could be used to up Hp and T. I think if I remember right, I could get up to like 9.2 or 3 to 1 CR??? Therefore a cam like a CC 268HE, (218 @ .050), could be used vs a stock cam at like 198/198 @ .050 or so?? Sorry, I forget??

I never got any farther along than wishing on this project..

pdq67
I think you need to replace a bunch of your 1’s with 2’s. 130, 155, and 160cc is stock sbf and smogger sbc territory.

Don’t L29’s have a non adjustable valve train too?
Right you are Travis.

My bad.

pdq67

Keith Morganstein
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Re: BBC steel head comparison

Post by Keith Morganstein » Mon Dec 03, 2018 8:28 pm

scottcleaver wrote:
Mon Dec 03, 2018 12:01 am
A little midnight contemplating. Rebuilding a 1990 454SS truck engine. *I will not be rebuilding it to its original 230hp version. I hope to build a 450-500 version. Given that the truck will need to be street friendly, adequate brake vacuum, run on crappy 87 octane gas and really just be a calm cruiser, I have compared two sets of factory heads as well as aluminum heads. For this comparison I want to stick to the factory steel head options due to price. A set of 049 heads versus the vortec L29 heads. I will get the correct piston for whichever head i choose as I don't want to be over 9.0 to 1 compression. I know there will be a ton of additional variables like cam, intake, headers, gearing, converter and others but I really want to just talk about the heads. Which head would you go with if it was made available to you?
Thanks
Scott
A simple and easy combo I’ve done many times.
Build it right with attention to detail and you can’t go wrong.

049 or the more common 781 heads
2.11/1.88 valves (with some bowl porting to go with the larger valves, fix the turn)
LS6 small dome pistons.
A good camshaft in the 225/235 @ .050 range. Hyd roller for reliability if in the budget.
New stamped steel rockers or scorpion rockers.
Dual plane intake, 750-850 carb.

This will run great on pump gas, have gobs of tourque and great midrange power.
Automotive Machining, cylinder head rebuilding, engine building. Can't seem to quit #-o

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