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Discussion Starter #1
Please help me with the differences. I'm not so sure Moretec is correct.
I have a deal lined up on either sets and I don't know which ones to get.
Thanks
 

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If they are the same price, go for the 781s. I have heard they flow just a teeny bit more, stock.

But both heads are good and flow virtually the same.
 

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049's flow a slosch better on exhaust, they're nearly identical on intake. If you can, check guides to see which has the best fit, look to see if either has been knurled which is generally an indication that guide liners will be needed. I like to take an intake gasket and line it up on the bolt holes. It's not perfect but can be a fair indicator of casting shift - just check to see how well the ports line up with the gasket. I have a pair now that are as-cast but look gasket matched when I check 'em this way. Pick the matched pair that shows the least casting shift and has the best guides. Pass on any that look like anyone's ported on 'em.
 

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Discussion Starter #4
The 049's have not really been ported to say but have been smoothed out. They are knurled. They are bare heads for $100. I have rockers, studs and such to use on them if I go this route.
The 781's have been "rebuilt" by Pioneer. They have 5000 miles on them and look almost new. I'll have to check on nurling. I can get them for $250.
What do you think?
 

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The 049's have not really been ported to say but have been smoothed out. They are knurled. They are bare heads for $100. I have rockers, studs and such to use on them if I go this route.
The 781's have been "rebuilt" by Pioneer. They have 5000 miles on them and look almost new. I'll have to check on nurling. I can get them for $250. What do you think?
Knurled guides do not last long, maybe 20K-25k miles. If I were to get the 049's, I'd have new guides installed before use. Then the price would be about the same, less parts in the 049's. So the 781's would be the better deal.

Just my thoughts.
 

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Not that I'm aware of. Accessory holes on the ends of the heads help alot. It would be nice if the heads had hardened valve seats for unleaded fuel.

Maybe other here can give some suggestions.
 

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Get the 781's for the price. You would be wise to cc them first. Uncut they will probably be over 120 ccs. Both 049s and 781s are excellent BB oval port heads.
 

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From what I see, the 781 has .....73-85...oval...OPEN...454, 118cc chamber, 256/114cc ports

049 353049.....73-84...oval...OPEN...454, 122cc chamber,
255/119cc ports

781 has the smaller comp chamber , if you can handle the compression , goferit. It might pay you to run some simple roller TIP rockers, to keep the valve guide wear down even with knurled guides. Use some good oil that has good wear additives in it.
 

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Discussion Starter #10
zdld17
So Mortec is correct? Or did you get this info from Mortec? I have seen conflicting numbers on other sites. Hopefully they are correct. It can make a big difference when building an engine and calculating compression. This is exactly the kind of info I am looking for.
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zdld17
So Mortec is correct? Or did you get this info from Mortec? I have seen conflicting numbers on other sites. Hopefully they are correct. It can make a big difference when building an engine and calculating compression. This is exactly the kind of info I am looking for.
Thanks
I don't mean to step on any toes, but I've seen numbers ranging from 110ccs to 120ccs for 049 and 781 heads- many from reputable sources. The answer is that you must cc your own heads and go from there...
 

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http://www.mortec.com/castnum.htm

This information mirrors what I have in head data also.

I consider it correct. You may trade some exhaust runner cc's for few compression cc's and I would rather keep my compression. exhaust flow can be adjusted with cam or rocker ratios. You are not gonna see it on the street.
 

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I have a couple sets of 781's and 1 set of 049's. all my heads cc'd at over120cc's, 781's 122, and 124, 049'sat 122.
cc them to know for sure. Motec is NOT dead nuts accurate on this info, GM spec for both theese castings is 119cc's.
I have ported quite a few sets of theese heads and there are VERY minimal differences between the casting #'s, I say pick the heads that are in the best shape and need the least amount of work.
 
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