289 smog heads???
10-20-2009, 06:12 PM
#11
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Location: Victoria, Australia
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Ive fully ported a few sets of both early 289/302 heads and a couple sets of 5.0 heads from roller engines. One thing you REALY dont want to do is mess with the short turn in the port floor. If you want to kill flow and make them run like crap, grind that puppy down so it looks straighter. Smooth it but dont change the shape, the rest you can hog out pretty big.
Still you wont get the same power you will from a decent set of aluminum heads. For a stock looking build you can do ok on power if you are smart about where you remove metal.
Still you wont get the same power you will from a decent set of aluminum heads. For a stock looking build you can do ok on power if you are smart about where you remove metal.
10-21-2009, 03:12 PM
#12
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Location: PA
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The original design was not bad, but rough foundry work and addition of smog bumps usually made a mess of the ports. If you smooth off the smog bumps and open the gasket surface to the original contour of the port they work pretty well.
10-21-2009, 08:48 PM
#15
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bowl work, blending into ports and under the valve really help sbf heads, it takes some majojor work to get them to flow good though, id look into aftermarket heads even gt-40's unless you are experienced at porting heads, otherwise grind the bumps off and do a gasket match about 1" into the head, you might see 10hp if your lucky.
Frankly a cam (especially a custom one) will give much more improvement than a gasket match, a dual pattern cam with 10-15 degs more exhaust duration and 108-110 lca with a higher lift rocker on the exhaust will wake up a poor flowing head.
Frankly a cam (especially a custom one) will give much more improvement than a gasket match, a dual pattern cam with 10-15 degs more exhaust duration and 108-110 lca with a higher lift rocker on the exhaust will wake up a poor flowing head.
Last edited by htwheelz67; 10-21-2009 at 08:52 PM.
10-22-2009, 10:16 PM
#17
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Join Date: Mar 2009
Location: Victoria, Australia
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bowl work, blending into ports and under the valve really help sbf heads, it takes some majojor work to get them to flow good though, id look into aftermarket heads even gt-40's unless you are experienced at porting heads, otherwise grind the bumps off and do a gasket match about 1" into the head, you might see 10hp if your lucky.
Frankly a cam (especially a custom one) will give much more improvement than a gasket match, a dual pattern cam with 10-15 degs more exhaust duration and 108-110 lca with a higher lift rocker on the exhaust will wake up a poor flowing head.
Frankly a cam (especially a custom one) will give much more improvement than a gasket match, a dual pattern cam with 10-15 degs more exhaust duration and 108-110 lca with a higher lift rocker on the exhaust will wake up a poor flowing head.
That's right!
10-27-2009, 11:56 AM
#19
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Join Date: May 2009
Location: PA
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Yeah, there were a lot of heads that had the bumps, but were not drilled for the injectors. Whether they were drilled or not, the exhaust flow was pretty bad. I'd estimate the improvement at more than 10hp on smog heads, I believe I got more than that on my non-smog 65 heads.
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