Whatever you do, don't port match to the gasket.................make sure there is a reversion (meaning that the intake side is 1/32 to 1/8 smaller than the ports on the head[this is were CNC porting comes in, you measure your manifold passages, then the intakes on the head......and the CNC will get them all exactly withing .001"])................this has been proven on dyno's......and offers real HP gains vs. porting directly to the gasket. And hp gains.........anywhere from almost none to 4/5HP depending on the RPM, and remember that both the Edelbrock Victor Jr. (which I would recommend) and the Super Victor Jr. (like on my motor) only start to produce HP after 3900rpm....................less than that and they will not perform as good a dual plane. Here are the dyno numbers on my 408.....but it has about 3 points more compression with over .700lift and was using an 850 Holley; 3500rpm - 270hp 3600rpm - 280hp 3700rpm - 290hp 3800rpm - 300hp 3900rpm - 308hp 4000rpm - 328hp 4100rpm - 348hp 4200rpm - 367hp 4300rpm - 387hp 4400rpm - 408hp 4500rpm - 425hp 4600rpm - 444hp 4700rpm - 460hp 4800rpm - 476hp 4900rpm - 490hp 5000rpm - 502hp 5100rpm - 517hp 5200rpm - 529hp 5300rpm - 535hp 5400rpm - 550hp 5500rpm - 564hp 5600rpm - 577hp 5700rpm - 589hp/max torque of 544lbft 5800rpm - 594hp 5900rpm - 603hp 6000rpm - 610hp 6100rpm - 614hp 6200rpm - 617hp 6300rpm - 622hp 6400rpm - 626hp 6500rpm - 631hp 6600rpm - 637hp 6700rpm - 639hp 6800rpm - 642hp/torque of 499lbft If I were you, I would call Steve a Crower cams.............or pick any cam manfacturer...................give him the specs of your motor and ask his recommendation for a hydrualic roller..............somewhere I read about a new type of hydraulic roller that offered more usable hp in the 6000rpm+ range.............I just can't remember who...........I'll dig through some of my Drag Racing magazines.
comp cams is who i have been talkin with and they hooked me up with a cam based on the 225 afr heads, afr said the 72 cc would keep me good on pump gas and they think a victor jr would be fine, thanks for the info i think the combo im goin with would be pleasing, this is my first engine ive pieced together, told em i would not be goin over 6400 rpm they said the cam would be fine, been puttin alot of thought in it just like info from you guys that have been in my place
Important thing to remember about the internet. When you ask for people's opinion they will give it. Welcome to the boards. Nice looking Falcon and I bet the Mav will look even better.
You're certainly right and the head itself(especially one that has been CNC'd like the OP's) would be the deciding factor for the intake manfolds port exit final sizing. I usually leave an intake manifold .010 -.020 short of the head port on all sides(as some of the biggest name builders have instructed me).. to allow slight variances during assembly and avoid having to use locating dowels on the manifold/heads. Not to mention that such ultra precise matching goes right out the window when any machine work is done down the road.. and even the big builders don't worry about a few thou variations or ultra slight mismatches so long as the intake port is slightly smaller than the heads entry and doesn't cause shearing or tumble. Also.. I've not come across a way to assemble an intake manifold within .001 inch of head ports without locating dowels. Even scribing them would not allow that level of accuracy IMO and experience so far. Scribing gets you pretty close.. but unlikely to hit that exact mark right to the thou every time you install it. Would be curious to know how you match yours? But then again.. I balance my rotating assemblies individual components to the 1/10 of a gram and keep all my bobs within 1/2 gram of each other too.. so I'm certainly "all in" for ultra-precision blue printing. The little things don't mean as much by themselves.. but they certainly are cumulative and add up to a superior motor in the end. PS. @ the OP. Comp is good to talk to.. but just remember that AFR is the one who designed the heads and they have tested those heads on the dyno far more than Comp has. AFR would be my first phone call in regard to cam selection.
Ok, giving my best secrets away................................I use studs and machinest blue on the intake(infact, when you start to mock up the motor after all of the machine work you do the same thing, only measuring a little more accurately with a coordinate measure machine/tool).................if you are doing this after the fact. Personally I like to do it before the heads/intake go on the motor and intake goes on. Most of the hi end machinest have some type of coordinate measuring machine/tool and you measure the head/ports intake and exhaust along with the intake manifold.....................(don't forget to to also match the spacer to the carb and the top of the intake along with shaving the gaskets to match), then take the coordinate measurements and import/export them to the CNC...and there you have it. I think the only motor I ever dowel'd/pinned was the Flathead V8, because you are trying to place the combustion chamber dead over the cylinder................and we did this again with the machined block/head..............put the heads on without any internal components................marked the cylinder/combustion chamber with a laser.........................anyway..................everyone has their own process for getting everything straight.
LOL.. but it feels good to share sometimes. I too use studs on many builds.. but the holes are usually just far too sloppy to really be able to rely on them for precise or repeatable placement. I've also seen some guys weld or pound dead soft aluminum plugs into the holes and then redrill them to stay tighter on the studs shank,, but hell.. by the time I do all that I can just roll the mocked up motor over under the drill press and drill it for dowels. That's why I like the .010 to .020 tolerance along with single plane manifolds with decent line of sight to the center ports. Makes it easy peazy to get damned close enough for the girls I race against.
Welcome Welcome from Moyock NC......I work in Norfolk so if you ever need a hand shoot me an email or PM.....ski2007hd@gmail.com
