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  #1  
Old Nov 13th, 08, 11:59 PM
Zenpig Zenpig is offline
 
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Default Worth it to port/polish sbc head 3947041 ?

I bought a camaro with a 350 / loppy cam / t350 / 4:10 posi. Runs pretty good, but found out it has heads from a 305. Found some 3947041's, ready to bolt on. I'm wondering if it would be worth it to do some slight porting and polishing ( never done it before, but would like to try - I'll practice on junk heads first). Or, should I just leave them alone. I don't know how rare these heads are, and maybe in 10 or 20 years someone (maybe me) would want them to complete some numbers matching combo, and if there ported, it would deflate the value. And maybe porting these heads doesn't really add much flow, but maybe it does.
I know new aluminum heads flow much better , but this car is just for cheap -inexpensive - fun, not for detail (67 camaro shell in storage is for serious).
Also, there's an X on the bottom of these heads, are they special?
Any advice would be greatly appreciated
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  #2  
Old Nov 14th, 08, 12:51 AM
Dave427 Dave427 is offline
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Default Re: Worth it to port/polish sbc head 3947041 ?

Well someone might of put the 305 heads to bump up the compression, on a stock bottom end with dished pistons. The 305 heads might be 60cc. The 041's are a great high performance head , they are 64cc. I am just not sure if you will see a gain by the head swap.

Dave
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  #3  
Old Nov 14th, 08, 10:31 AM
1966_L78 1966_L78 is offline
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Default Re: Worth it to port/polish sbc head 3947041 ?

I have heard, for the best benefit you really need to know what to do when porting heads... Its not just make the ports larger and smoother... Head porting is a cross between an art and science...

Unless you know someone willing to lend their experience, you might not do much good... You might even do harm; not only loss of "collector" value, but you might hit a water jacket, etc...

A lot of time and some expense (buying tools, new valves and springs, maybe pressing in new guides, enlarging spring seats and hardened seats installed, etc)... You'll also want to magnaflux the heads first and check the deck thickness, etc, to make sure they are good before you spend hours playing with them...

With many "aftermarket" heads, you get something actually "designed" to work better than stock, and often with all new hardware... A bit more money, but could be alot less aggravation... Plus, with aluminum, you'll save a little weight...

You also need to determine what your entire combo is, and determine if ported heads benefit you at all... As mentioned previously, depending on chamber size, etc, swapping heads may actually hurt your performance...

IMO, unless you need "stock" heads (for a certain class, say F.A.S.T. racing), looking for that last 10th (or last few 100ths) or you really want to spend the time and have someone to teach you, not worth the effort...

I have know of several guys that ported their own heads (more than gasket matching and blending). Several ruined their heads, and a few gave up after hours or work...
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  #4  
Old Nov 14th, 08, 11:50 AM
Jason Snyder Jason Snyder is offline
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Default Re: Worth it to port/polish sbc head 3947041 ?

Quote:
Originally Posted by Zenpig View Post
I bought a camaro with a 350 / loppy cam / t350 / 4:10 posi. Runs pretty good, but found out it has heads from a 305. Found some 3947041's, ready to bolt on. I'm wondering if it would be worth it to do some slight porting and polishing ( never done it before, but would like to try - I'll practice on junk heads first). Or, should I just leave them alone. I don't know how rare these heads are, and maybe in 10 or 20 years someone (maybe me) would want them to complete some numbers matching combo, and if there ported, it would deflate the value. And maybe porting these heads doesn't really add much flow, but maybe it does.
I know new aluminum heads flow much better , but this car is just for cheap -inexpensive - fun, not for detail (67 camaro shell in storage is for serious).
Also, there's an X on the bottom of these heads, are they special?
Any advice would be greatly appreciated
those 041x heads are worht alot of money ! rebuilt over 500.00 bucks . sell them on ebay .
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  #5  
Old Nov 14th, 08, 12:08 PM
kettbo kettbo is offline
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Default Re: Worth it to port/polish sbc head 3947041 ?

A lot of good advice here.
Unless doing a full 100% resto on a matching numbers car...the 041s and 041X would be better sold to finance other stuff. They do deliver the bacon but it is bacon dated 1970 or there about.
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  #6  
Old Nov 14th, 08, 5:06 PM
Zenpig Zenpig is offline
 
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Default Re: Worth it to port/polish sbc head 3947041 ?

Thanks for the advice, y'all. I think I'll forget about the porting and just freshen them up. Combustion chambers are 64cc, so I shouldn't lose much compression, but the top end should improve over the 305 heads - any advice on cams? It's supposed to be a Crane fireball with 280 duration - guess I'll make sure as long as I'm taking stuff apart, but as long as I'm in there I might just want to get a new one.
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  #7  
Old Nov 14th, 08, 5:11 PM
pdq67 pdq67 is offline
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Default Re: Worth it to port/polish sbc head 3947041 ?

Bowl-blend and dingle-berry port clean them up is all you need to do, imho.

pdq67
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  #8  
Old Nov 14th, 08, 5:39 PM
henpecked henpecked is offline
 
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Default Re: Worth it to port/polish sbc head 3947041 ?

I went consistant 11.70s with a .510 hyd. summit cam in 406 in a '69 full body + rollbar chevelle bracket car on pump gas using 186's (which are very similar to 041s), so there is potential there. Same car and basic engine combo (just less cubic inches at 355 instead of 406) would go 11.90s.

Usually, there is a huge casting/machining lip under the valves on these heads..just a little time smoothing this out under the valve, coupled with a good valve job, and they work very well for a stock head. The kicker is that these days the old GM heads need so much work that it's usually easier and cheaper to get vortecs or new aftermarket heads.

But if you've already got the 041s (they should have bolt holes--every 041 I've ever seen had them), and you're gonna rebuild them anyway, a couple hours work under the valve will be well worth the effort.
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  #9  
Old Nov 14th, 08, 6:02 PM
pdq67 pdq67 is offline
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Default Re: Worth it to port/polish sbc head 3947041 ?

What henpecked is saying is!

If you need to guide them, then you want screw-in studs vs stock pinned and then larger dia. valve springs than -142's and such that you may be better off buying a set of aftermarket heads.

But, they are good, just bowl-blended and dingle-berry casting flash port cleaned up dandy old double-hump chamber shaped heads!

pdq67
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  #10  
Old Nov 14th, 08, 7:29 PM
rkd rkd is offline
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Default Re: Worth it to port/polish sbc head 3947041 ?

Having done this both ways, I would echo the recommendations to stay with what you have or upgrade to some of the newer iron or alum heads.

If you add up the costs of rebuilding a set of heads, you can easily get $5-800 or more in a set of free, but old iron heads. I did a set of home ported irons one time, gained about .25 sec in et, and lost it when I replaced them with identical non ported stockers.

I went with some later performance iron heads, upgraded the springs, had the valves angle cut, and got a full second or more on the same engine, although acompanied by an intake upgrade. Still had $800 in them.

If you have a good running set of heads, I would just run them until you get to time for a major upgrade.

Unless, as I did, you just want to do it an see what is involved, and what the result is. If that is the case, go for it!

A new set of aluminum AFR's is now awaiting an opportunity for installation.
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  #11  
Old Nov 15th, 08, 10:52 AM
henpecked henpecked is offline
 
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Default Re: Worth it to port/polish sbc head 3947041 ?

Quote:
Originally Posted by pdq67 View Post
What henpecked is saying is!

If you need to guide them, then you want screw-in studs vs stock pinned and then larger dia. valve springs than -142's and such that you may be better off buying a set of aftermarket heads.

But, they are good, just bowl-blended and dingle-berry casting flash port cleaned up dandy old double-hump chamber shaped heads!

pdq67
YEAH! that's what i was trying to say!!
OH YEAH--if that is a set of 041X heads...DO NOT touch them, you'll find someone (stock/super stock racer or head porter) that will give you MORE than enough $$ for them for you to get some really good aftermarket heads...
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  #12  
Old Nov 15th, 08, 10:59 AM
pdq67 pdq67 is offline
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Default Re: Worth it to port/polish sbc head 3947041 ?

And don't forget that 305HO, -601 heads come with...........

1.84"/1.50" valves; with

Hardened seats;

A from 52 to probably 58 cc chamber size; and

A true double quench chamber, not unlike the original -461 Fuelie head; and

160 cc intake ports!

Suckers are good heads for a +12 cc dished piston 350 engine, imho, if that's what you have??

pdq67
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