Guest Posted February 26, 2002 Share Posted February 26, 2002 A lot depends on what you are trying to achieve Robin. Are you looking for one horsepower per cubic inch? What kind of drivability sacrifices are you willing to make? Will you be driving this car at -30 Celsius? What would you consider very poor gas mileage? 2 MPG ? 6 MPG ? These are all questions you have to ask before any engine buildup.<P>As for heads, you can spend thousands of dollars for head work but I suggest you do just the basics. The basics entail cleaning up the short side radius behind the valve and the bowl area under the valve seat. <P>Buy new valves and cut the seats with three angles so you get the correct seat width. Don't waste time polishing ports and combustion chambers, worry instead on the intake port matching and opening up the exhaust port a little. <P>I once spent 4 weeks, 8 hours a day, 7 days a week on a set of 351W Ford heads. If I hadn't did the first chamber so nicely I wouldn't have had to do the other 7 so nicely, remember this if you are doing this yourself.<P>Head work is an art, visualizing flow through a port takes a bit of abstract thinking and not everything you think you might know about fluid dynamics is true. <P>What exactly are your intentions? Link to comment Share on other sites More sharing options...
Guest Posted February 27, 2002 Share Posted February 27, 2002 Hey Chuck-thanks for the educational response. Nice to get professional thought provoking input, and I mean it!<BR>I obviously never really thought the process<BR>through, Engine short block is built to spec-nothing else,10/10, .60 rebore. I felt some cleanup and self blue printing would enhance performance w/o sacrificing fuel economy. I would not attempt to do myself-therefore weighing the option of having it done proffesionally. Any idea on cost to do? Is it worth the trouble. I have often read and heard about various results-but never about <BR>nail head applications. <BR>Thanks fellow gold winning Canadian.!!!<BR>(Had to do it) Link to comment Share on other sites More sharing options...
Steve B Posted February 27, 2002 Share Posted February 27, 2002 Robin,<P>There are a number of specialists that work on the Nailhead. The head is generally the limiting factor in performance applications. A well ported set of Nailheads flow at or above the level of an untouched Stage 1 455 head. As such, the engine can perform to almost that level (smaller size). Here is a comparison of some various Buick heads for reference: <A HREF="http://www.buicks.net/racing/heads.html" TARGET=_blank>http://www.buicks.net/racing/heads.html</A> . The cost will range from around $500 to $800. Link to comment Share on other sites More sharing options...
Guest Posted February 27, 2002 Share Posted February 27, 2002 Robin, If I had to pay for it I would just get a good valve job and forget the porting. On a highly modified and radically cammed engine a well ported head can be worth 50-100 HP depending on the engine.<P>On a stock engine you would likely only get 10-15 HP and it would all be high up the RPM scale. I would concentrate your resources on getting the details right, fuel system, exhaust, ignition etc...<P>I know it's tempting to do things while it's apart and the heads are an attractive starting point, but to be honest you won't gain much. <P>Now if you were slipping in a 290 degree duration .500" lift cam and a single plane intake with a double pumper holley carb and some headers then that is a different story. With such a combination, mild head porting can easily get you an extra 25-40 HP, not too shabby. Again all those gains will be in the 6000 rpm region. Here'a link to do it yourself head porting;<BR> <A HREF="http://www.sa-motorsports.com/diyport.htm" TARGET=_blank>http://www.sa-motorsports.com/diyport.htm</A> <P>For a nice street engine you should be able to get close to a horsepower per cube with a nice mild cam (275 duration and .475" lift)and dual plane intake running even a big Quadrajet with a set of headers and 2 1/2" dual exhaust. <P>This kind of combo makes a nice street engine that has a slight rump to it's idle that lets them know you mean business. Your vacuum should be in the 14"-18" of mercury range so you won't lose any power brakes etc. <P>Still wouldn't want to have to start her at -30 C without being plugged in though, and your mileage will take a serious hit. Expect 8-12 MPG depending on the gearing and car size. What kind of power level or quarter mile time do you expect? Link to comment Share on other sites More sharing options...
Guest Posted February 27, 2002 Share Posted February 27, 2002 What if any improvements can be done to 65<BR>401 heads? Cam application with same as I am about to complete my engine rebiuld for my<BR> 65 Gran Sport. Link to comment Share on other sites More sharing options...
Guest Posted March 6, 2003 Share Posted March 6, 2003 Hi i am new to this page, i am breaking down my 77 350 and i was wondering will i see alot of change in horsepower with this set up, stage 1 intake, TA212 cam, double roller timing chain,lifters,rebuild my heads (wondering if i should get the heads ported intake and exhaust or should i get the regular 3 angle valve job), holley carb(600), larger valves, all of this is going on brand new any suggestions would help Link to comment Share on other sites More sharing options...
Turbo Loyd Posted March 6, 2003 Share Posted March 6, 2003 [color:"blue"] To maximize the gain you should get out of this combination you should raise the compression ratio from 8.0 to one to at least 9.0 to one or higher. Buick 350s like a lot of carburetor so the 600 cfm Holley carb will limit your output and definitely lower you mileage Link to comment Share on other sites More sharing options...
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