New aluminum heads or not

why do you emphasize a polished exhaust port?

just wondering

an engine builder that worked for a nascar team told me that it would help at high RPM's...no turbulance....better flow. Not matched ported, but smooth out the casting flaws. I went to the trouble to match up the water ports on my 400 sb. mabe it didn't help anything, but it sure looked good...LOL. I believe any place you can help flow, (being engines are just air pumps,more in more out) you help performance. And if you do it yourself the only thing it cost is your time and $20.00 worth of stones and sand paper.  

GO FOR IT! If you have the money to spare it would be well worth the power increase. The AFR heads are leaps and bounds ahead of your old heads!!! Before you buy make sure you call AFR and consult with them, concerning the intended use, and what ever hardware may be different.  

sharp corners, edges, burrs, quick turns all cause heat build up or flow restrictions.  If you have a smooth ehaust port with none of these obstructions, it will run cooler.  This also applies to intake runners, water jackets, etc... Any time air, coolant, or oil cross one of these, heat/turbulence is generated.  If you have a burr or rough spot in your exhaust port, heat will build up on that spot and increase your head temp.  The same applies to oil and coolant.  If your intake runners are rough or have obstructions/burrs, the flow will be comprimised and create turbulance which will affect your charge velocity and reduce HP.

I have a 357 (.040 over 350) in a 73 Chevy 3/4 ton 4x4 beater truck that I use for hauling fire wood.  It is a flat top 9:1 engine with stock 350 76cc heads, Aluminum intake, RV cam with 1.6:1 roller tip rockers and a 780 Holley dual feed carb.  I have access to a dyno and I ran when I built it initially.  It was producing 335HP and 378ft/lbs torque and was running about 198F temp on the stand.  I pulled the engine apart, ported and semi-polished the intake and exhaust ports on the heads and intake runners on the intake.  I also gasket matched the intake and heads at the same time.  While I had it apart I cleaned out the burrs and edges on the water jacket ports on the heads and block so it was a nice smooth flow for the coolant.  These changes gave me an additional 17 HP (352) and 10ft/lbs torque (388).  The water temp dropped 16F to 182F.  And just because I had it laying around, I added a louvered windage tray to the oil pan and gained another 13 HP (365) and 2 ft/lbs torque (390).  

So if you ask me if it is worth it to have a smooth intake, exhaust and coolant flow.

But, in my opinion, there is no replacement for displacement!!  build a big block and get all of the power and torque you'll ever need!!  

big block all the way, you cant beat the low rpm torque.  

guys this thread is 5 yrs old  

Yet it still gets people replying. Shows how the web will never die.  

i didnt even notice now i feel stupid thanks 70rsss396  

there is no comparison between camelbacks and afr.those old heads would need serious work to flow like a set of eliminators anyone who says your power gains will be negligable is nuts.the 190cc flow like 270 out of the box