I'm looking for info on the 049's, my dad's LS5 has them. I checked them out on www.mortec.com (http://www.mortec.com) but I was hoping for a little more. I'm curious what the LS5 had originally from the factory and how these two heads compare. From what I understand, the 049's work best with domed pistons? I'm not sure what are in the block now, but the car runs pretty strong. It dynoed at ~400fwhp with these heads, crane cam (not sure of specs off hand), performer rpm manifold, 1 7/8", 3 1/2" collector headers, roller rockers, and HEI distributor. Any thoughts?

Thanks a lot!
Mike

Find a set of closed chamber ovals you won't believe how much better it will run because or the compression increase. The 71 LS5 I have came with 820s. which are sort of a strange looking open chamber with a huge relief around the exhaust valve in the chamber.

A 1970 LS5 should have 290's and not 049's

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Those -820's sound like the really big open chambered smoggers of the early to mid '70's... Maybe later??? pdq67

Thanks guys! I guess I'm still curious why the guy who built the motor would have switched to the 049's, assuming he had the option, which I think he did based on the rest of the motor. Any ideas why he went with the 049's over the stockers?

Thanks again!

Here we go!

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<BLOCKQUOTE>quote:</font><HR>Originally posted by Milan:
Here we go!

<HR></BLOCKQUOTE>

Where we goin? I got my 6 pack cooler and im ready...... http://www.chevelles.com/forum/wink.gif

Better hope the motor don't have open chambered pistons or you might be shaving the pistons. If it has the open chambered pistons like my TRW 2465F forged piston your compression should be in the 9.6-10.2 range depending on the cc of the head. If it has a flat top piston or the closed chambered dome you might want to go with a closed chambered head if you can find them cheap enough and don't mind to put 600.oo in them putting valve guides and 2.19-1.88 valves installed in them.

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The previous owner probably installed the 049's to reduce the compression ratio in order to run pump gas. The factory LS-5 10.25 CR with a stock or small cam was probably causing a detonation or ping problem. The 820 heads were '71-'72 402 and 454 items.

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My 820s have a Jan. 71 casting date on them. I have never run the things when I put the motor together I used 215s. Has anyone tried them I am just curious.

I'm using them on a 396 with the big valves and some bowl work. 10.0 CR with L78 cam, pistons, intake, and carb. Since I haven't ran anything else, I don't have anything to compare them to.

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