Putting a 302 in my sons 73 Mav. +.030 Hyperutectic Pistons 9:1 CR ARP Rod Bolts Stock -68 model heads Headers Dual plane intake 600CFM Holley VS C4 with shift kit and stock converter 2.79:1 gears I want something streetable with this combination, but of course a 17 year old wants to HEAR the cam. Any ideas guys? I've been leaning toward a CC 268H or CC 270.
SUM-K3601 - $62.95 Summit cam/lifter kit. .471"/.471" lift; 276/286 adv. duration; 218/228 duration @ .050"; 114 lobe sep. angle Crane 363942 - $169.95 Cam/Lifter kit. .484"/.512"; 272/284 adv; 216/228 @ .050"; 112 lsa Comp Cams CL31-234-3 - $179.95 Cam/Lifter kit. .477"/.484"; 256/268 adv; 212/218 @ .050"; 110 lsa These are just a handful of camshafts out there. Personally, I don't care for single pattern cams but others like them. These specs are something you can keep in mind while shopping around. Good Luck!
Thanks guys, those recommendations seem to be in line with my way of thinking. I'll let ya know how this engine works out once its in and running. brad
Comp Cams CL31-234-3 - $179.95 Cam/Lifter kit. .477"/.484"; 256/268 adv; 212/218 @ .050"; 110 lsa I swiped this grind from Shadow's short list. The reason I like this cam: The split duration will make the cam sound bigger than it is. The small durations will work best with the stock converter. Also with the highway gear, but being a 2.79, there isn't a cam out there that will help that. On the other side of the coin, you are dealing with a young man that probably should start off with that gear for safety and economy. Let him get some experience with the car and grow into a job that he can afford to use more fuel, then let him make the switch to a better gear. I wouldn't mess with the 270 from your short list. Too much duration for your overall combo and goals. Being a single pattern, it will also idle much smoother, even with more duration. The exciting sound can be had with a smaller cam like I mentioned, with dual patterns. The 268 is good, but the sound won't be there. Another good thing about a dual pattern cam, it will band-aid the low flow exhaust ports on those heads you are using. A single pattern, like 268 and 270 Comps, works best with a head that has much free'r exhaust flow. Good luck Dave
Comp Cams CL31-234-3 - $179.95 Cam/Lifter kit. .477"/.484"; 256/268 adv; 212/218 @ .050"; 110 lsa XE256H .477 / .484 i run this cam in mine... i run 14.220 at 96... it runs good... rpms out at 5500 rpms... i am using almost the same setup as you .. it is a good cam i want the xe268h .512 intake and exhaust.. would run me a little better on my setup.. but then i need a dif intake... i have the 289 performer.. with a 600 edelbrock carb. and i am running a MSD system.
That gear ratio will be a slight hinderence (sluggish on the low-end) with the cams that have been suggested, but you can always change those later. Does that motor have screw-in rocker studs? If not, you may want to keep the lift under .500. I went with a Comp 268 (and I have 3.55) gears. I would have liked a 270 Magnum, but it's a .501 lift, and I don't trust the stock pressed-in studs, and I didn't want to spring for screw-in (I'd rather just save up for aftermarket heads instead)...
Nope, no screw in studs on this budget built. I went with the 268H as I had a choice of 5 cams in the kit I am using. My machinist and I agreed this was the best choice as far as performance, valve trane considerations and the stock gear & converter. Haven't yet decided on an intake manifold or type of headers yet. Probably go with whatever intake I can get a good deal on for now. I'm gonna play around with several carburetors as I have a lot of holley stuff. Probably try a 390cfm and a 600. Here's a link to some interesting test data. Seems some of the higher rpm designs did a lot better in the lower rpm that one might think. Any opinions on what headers fit the chassis best? brad
hooker headers fit without mods. summit headers dont fit i tried them in the beginning. had to go with hookers, and they dropped right in and arent bad on the pocket book
Don't put that 390 carb on that 302. Performance will fall flat at about 4000 rpm. It will begin to pull raw fuel into the cylinders and ruin that nice bore job and gaul those pistons up real bad. the 600 cfm will be close to ideal for the street unless it is a mechanical secondary. You could go down to 500 cfm for crisp throttle response on the street or as high as 680 to 720 with vacuum secondaries for maximum runs on the track. The cam you selected should work real well with most dual plane intakes on the street and be easy to drive. If you want absolute performance a long runner single plane rated to 5500 rpm or thereabouts - nothing for over 6000 because the camm and heads won't work well at that rpm and the runners will be too large and too short to make best use of the cam.
Not to be argumentative but how can an engine run fine on a two barrel and have such problems running a small 4 barrell? I see no reason that raw fuel would be dumped into the intake. Are you saying the vacuum signal will be so high that it will overcome the floats and needle valves? In reality the 390cfm 4 barrell is larger than a 500cfm 2v and plenty of people have run those successfully. When I dirt tracked, addmitedly a SBC, we ran lots of different carb combinations on the same engine to suit different track rules without problems. brad
I don't know why a 390 4v would hurt either... The stock 2v is only around 300 cfm and doesn't dump fuel when topped out. The 390 would get better mileage too compared to the 2v. Dave
I did some calculations using this formula to determince CFM requirements for the engine: CFM= [(Cubic inches x RPM)/3456)]x Volumetric Efficiency. FOr our engine: 306x5500=1,683,000 1683000/3456=487 487 x .85=414CFM. The holley 390 with the K&N Stub Stack that I have should be pretty darned close to that and should work well with the CC 268H, Tri-Y headers and dual plane intake. I just can't see any reason that a properly rebuilt and tuned 390 would dump raw gas into the engine. brad
yes, but the 600 holley (vac secondary) has proven to run quite well on a stock/modified 302, & will leave some room for any future modifications. the 390 would be topped out now and the secondaries opening up quite a bit more than the 600 would. the 600 gives you more flexibility for the future. jmho
Brad, the only problem with the 390 is that it won't flow well enough to take advantage of that cam. You won't damage your engine. Not sure where Paul got that from. That calculator you are using is finer I guess, but it always comes up conservative. It is a flat calculator for cfm required, but it does not factor rate of acceleration. You can and should run more than 414cfm for optimum results. Most people with your combo are running 600cfm. The 390 would be an OK choice for economy and to get an electric choke on there, not much else.
