What contributes to fast revs is lots of power compared to the weight to be moved. Now this takes different forms, a F1 racer needs lots of high RPM horse-power and can get away with that because like a crotch-rocket motorcycle, it doesn't weigh much. As vehicle weight goes up so does the requirement for torque to launch it, although once moving it needs horsepower to go fast. Problem is that with engine design, what's good for torque isn't necessarily good for horsepower and versa.

The Z car is of moderate weight so you can cut some torque requirements in favor of horsepower assuming you want to hear the engine winding on the highway. This is easier to do with a stick gear box, automatics are not so happy on the street with a high winding motor since this drives you into a loose torque converter to accommodate the cam and resultant torque and power curves.

However, a 302 has no special intrinsic revability vis-à-vis a 327, 350, or 383. In the end vehicle weight and gear ratios will make more difference than stroke. The big advantage of a 3 inch stroke SBC is that it's easy to stuff a long rod into the block. This helps a little on breathing and reduction of piston side loading, especially with a long duration cam and high revs. But these attributes really don't show up on anything but flat out race engines at race speeds. So chasing 6 inch or 6.2 inch rods on a street motor is some expense and no effective use of the gain, your money is better spent elsewhere.

The 302 is not known as a torque monster mostly because of its cam timing and factory intake configuration. Certainly a milder cam and dual plane manifold would restore mid range torque and in a light weight chassis driven on the street wouldn't cost much top end so as not to be able to scare the daylights out of anybody at the stoplight. Ford has used a 302 quite successfully in grocery getters for many years, so the torque is there if you want it.

A big problem I have with the 302 SBC is energy density, unlike the 302 Ford it’s a heavy engine that had growth to around 350 inches envisioned from day one, where-as the Ford is really size optimized for about 300 inches. Yes you can make a SBC a lot bigger into the range of 400 inches and you can take a Ford out to around 350, but you’re really starting to make significant compromises to it. When FoMoCo stretched the 302 to 350 they redid the block adding almost an inch of deck height to it. Chevy to make a more efficient 302 should have taken an inch of height from the SBC, but then you couldn’t stuff really long rods into it, so around the circle you go trying to figure out which design is more effective. So for the SBC, I prefer engine sizes in the range of 330 to 360 inches, unless you’re springing for raised deck block.

Unless you're planning on revs over 5800/6000 rpm there really isn't any rocket science that needs to go into titanium spring retainers and locks. Same goes for knife edging counterweights, it's just not needed in a non competition engine and removal of material from the counterweights can get mighty expensive if your balancing emporium has to start putting Mallory metal into the crank to get it balanced.

The aluminum flywheel is a big help again with a lightweight car, you don't need a heavy flywheel to help with the launch, and in fact a heavy flywheel will only encourage wheel spin coming out of the hole. So aluminum will help the engine to rev without aiding wheel spin. 

Short cams with lots of lift don't last in street driven SBCs. The pre roller block SBC likes to digest cam lobes and the problem only gets worse with lots of lift. This is a bigger problem with today’s oils which are largely stripped of things like ZDDP. This stuff was put in the oil specifically to lube the lifter/lobe interface. The lack of ZDDP and similar anti-scuff compounds is why the manufacturers have gone to roller lifters and those manufacturers that didn't like GM have put in thrust plates to stop fore and aft cam movements. You can crowd a lot of flat tappet lifter and cam lobe longevity on to your side of the equation by running a cam bumper; this takes reacting cam thrust loads off the lifter/lobe interface and greatly extends their life.

Bogie

again bogie, wow. and a HUGE THANK YOU to our gear head friend serving in the sand box. (i am a former marine sgt) so keep safe and get yourself home to beat the crap out of this high windin' hot rod!!!! one real quick question on parts already aquired... the early mouse motors had what is called small journals. the main saddles in the block call for the 2.3 inch ground crank (which with the 283's arm, i am comfortable assuming you have.) it is the h- beams you mentioned that made me wonder if you are aware of the differences. -large journal mouse had 2.45 inch main saddles and used a larger 2.1 inch rod journal, the small journal arm will require  a 2.0 inch inner dia rod. just a heads up on a possible problem. also having the rods... what are the length, and you mention 302 pistons... are they all gonna jive? (rod legth, over bore, dome,  i'm lost as far as what hands on time you have with the engine so i appologize if i am getting into old info. i like the 302. a lot.

what are your ideas for the rev range on this sucker? 302's are known for liking to turn some revs. you have fantastic heads and a entry level street roller will get you into some really respectable performance. as bogie said, dur vs. lift issues are a trade off. cam companies make short cams w/ big lift numbers,problem is that they abuse the rest of the valve train quite a bit. i.e. valve springs...i have had a cam in a 327 i run for 3 years now i love it it is comp cams part no. 12-772-8.  248deg@.050 intake lobe and 254deg@.050 it has a 110 deg sep ground in which is good for flattening out the peaky-ness of the cam somewhat lift is .576/.582 w/1.5:1 rockers. your car is nice and light so an app like this is perfect. compression should fall between 9.5 - 10:1 (to keep the dur happy) comp 818-16 rockers are now force oiled which means they live longer on the street than solid rollers of a few years ago...basically the stick and lifters are the only "trick items you lack in having yourself a roller mouse. allow it a 3000 stall and 3.90ish rear gear a stick shift is great, but if you're into auto's a th350 will live and perform great. run a vic jr and 650 dbl pmp holley. i got my cam off the truck at super chevy along with the lifters for really reasonable money. 215.00 for the cam, and 260 for the tappets.this cam is absolutely driveable, has a cocky sound (there is NO sneaking it home) doesn't abuse the springs... matter of fact i run the cam with 155# seat pressure comp 939-16's @1.950 install height. with the tight .016/.018 lash i've been in there several times but have yet to run in to a serious variance.track time will dictate frequency of adjustment. i spray the motor with a 150 shot of n2o and the cam loves it. it is a fun car and with all the advantages of todays grinds, i hope you go roller to see for yourself how awesome the heads are you've invested in. my heads (on this motor) are no where near compareable i run 327 inch 10:1 gm cast 186 heads W2.05/1.60 valves, 1.6/1.5's, short turn and minor bowl work 1 3/4 hookers,3 in exhaust, vic jr., worked 750 holley (i think it is too big, more for  track times than street time) in a 3350# 70 camaro,3000 stall foot brake, 3.90's, no spray (street rubber) actually i ran 265 50 15 bf radial *** good for ZERO traction!  i left at 2000 and tried my best to flasah the convertor without losing all traction,shifted at 7100 and pulled down  un tuned 7.50 @95mph 1/8th mile times. i love the response, i love that it doesn't act stupid in town and i love that it will romp. your car being lighter, and having the afr's will be miles ahead. (resist the temptation to get a "bottom of the page" cam. you'll be so much happier.) i hope info on my numbers help point you in the direction you are looking for. i have a few small blocks together right now and can tell you what i've gathered from this, or, that mod... i know your time is limited so anything i can do to give you a little piece of home, or, of your hobby... fire at will. thanks again bro. 

Bottle,

that 327 sounds like a real terror.  I  cant imagine turning 7100, hopefully soon i wont  have  to.  I got small  journal rods,  to  go with the small  journal  crank,  and  the  small journal block. 5.7'' rods, and TRW pistons for the old 302's i think  they are  10.5-11.3,  somewhere  in between there. The crank is actually an old  military crank,  on  www.mortec.com, it actually says "military tank use" now, when  the  put  sbc's in  army tanks,  im  clueless lol, but  thats what  it says. It was  never installed, when i  got it, it was infact  military. Im thinkin  the  army would make the cranks  stronger than just a regular 283,  but thats  just a guess.

 I am going to  run some kind  of  built 5speed, and  yes, i  have a 3.90 rear.   On the  RPM range,  i would be thrilled if i could safely turn 7000-7500, and make  power doing it, but the higher  the power band, the weaker the bottom end is, so i dont want the car to be undriveable at say,  2,000rpm. Like, i dont want  to  dread  traffic, or stoplights, or city driving.

It would  be  silly for  me to  have  bought these heads,  and then  skimp out on a roller cam,  solely because  of the price... which was really what  was scaring  me away from  them. That and the constant valve adjustment that  i hear about. I dont know too much about roller cams, except that they turn rpm's and allow  more  lift,  but  damn,  .576/.582  is nuts isnt  it? You suggest a dual plane? 

I  posted this in  the carcraft forums,  and  they suggested  i  try it over here, im glad i did.

I must plead ignorence... all the valve train numbers, seat  pressure and all  that  jazz (aside  from  cam and  1.5 rockers) i  have  no  idea what they all  mean. I did just  order a  SBC valvetrain book  of  amazon, and  it  should  be  here  tommorow, so that will help  out tons with all the  head and cam math.

I just picked up the new chevy highperformance (dec) at the PX, and theres a letter asking the  old 302 that jeff smith built using  6.00 rods,  and it got 25mpg with a supercharger, man i wish i  could  call  up  jeff and just talk his ear off with  questions. Hes with who? car craft now?

Im not exactly building  this  motor to  coax out that  kind of MPG, but anything above 15 on  the freeway would be heaven. I was first planning to make this somewhat of a daily driver, but that would  mean  this would  be a backup if me  355/4speed 79 malibu  broke, and  i  dont know if i could  rely  on this motor like that. I wanted  to  keep  the a/c  in the datsun,  but  now i fear  the  compressor will  be too  much  in  the way if i  run a  roller cam  for easy valve  adjusting.

Do  dual  planes perform  much  past 6k rpm? Jeff smiths 302 he built made 300 hp with  a  roller cam specing at... 210/220 degrees at  .050 and lobe sep. of 114 using 1.6 roller rockers, the  letter describes the  cam as "very small". He ran  afr 195's. So, 300hp,  in  a  rather  light car, would  be pretty  fun i suppose, but  i  would  like to  go  for a little  more.  Im not trying to get 25mpg, so if im willing to  make  some sacrifices with  mileage,  so  i can run a more rad cam, for more hp,  what would you  reccommend?

So  Bogie, i  should stay  away from  all that titanuim,  and knife  edging stuff,  correct? the  ol' camaros didnt  use any of  that,  and  they turned  8 grand.

If i  was  able to  make power at  7,250 rpm, would  it be driveable  on  the street. If i  didnt  beat the  dog #### outa the  motor,  would i really need to  adjust  the  valves all  that much?

hey, glad to know you're alright outthere...

 maybe i spooked you with the upper end limits of the grind i mentioned. just 'cause it will turn big rpm doesn't mean you have to spin it that tight all the time. like i said solids do need the periodic lash check, and often, a check is all it amounts to. some roller grinds are VERY aggressive and do need adjustment all the time, but the bad rap carries over to the more streetable versions causing a lot of guys to shun them. my personal deal with hyd. rollers is the tappets being so heavy. many builders counter the weight with valve spring seat pressure that feel causes the hyd. portion of the lifter to bottom or collapse.  

as far as intakes, if you are lookin at a cruiser, performer rpm's are really good. the vic jr. i mentioned is a smaller plenum single plane i use, but i like the track times if offers with the bigger cam.

the afr's you have man, i can't help but tell you, you made a great choice. the .576/.582 sounds big i know, but it is a solid and for actual lift at the valve you subtract lash. .576-.016  (.560) and the .582-.018 (.564)  your heads would handle that sleepin'!

i run an isky grind in my set up now and it spec's lift at .656/.617 i'm using 1.6/1.5 intake/exhaust rocker combo. and yep, ido see some street time with it.

Hello, I have a somewhat similiar build, but a 406 with six inch rods instead of 302.  I purchased a set of afr competition 180's and a air gap intake then had them both portmatched for the fel-pro 1205 intake gasket and comp cams extreme energy 12-422-8 with 1.6 pro magnum rockers and hyd. lifters 853-16.  Haven't driven it yet but it sounds awesome and some of the locals thought it was a solid the way it revs, and I was really shocked by the idle and the way it revs so quick  Idle is a little past noticeable and which thats what I wanted, and I am glade the guys convinced me to go roller.  Thought about going solid but I will driving this alot on the street.  Good luck with the build  

a406 and the shorter hyd roller,(218/224@.050) you mentioned is gonna have the torque to ripthe tires right off the back of that thing on command. i am really interested to hear how things go. seriously it'll be a stout mouse for sure.questions.. what is it in?(weight?) gear? stall? (hopefully near stockish, 1800-2000 i'm thinking.)  

It is in a 86 chevy 1/2 ton swb truck. I have a eaton locker, 373 gears, 350 trans, TCI breakaway stall, 2400 to 2600, scat rotating assembly, forged flattops and the heads are 74 cc instead of 68 to keep compression below 11:1, running 93 octane gas I was shooting for at least 450/450 and anything over that is just icing on the cake.  Local guy has a 406 with camel humps and a flat tappet 470/480 lift with 350 trans in a 85 1/2 ton lwb and he is talking much trash.  not sure what the weight is on this truck probably at least 4000 pounds.  

Bottle,

Thanks for pumpin me up about those heads, and insuring me i just made the right choice. I finally started reading, making decisions on my own, i bought those back when i group of people told me that would be best.

I just got a new book Chevy Small Block Cams and Vavle train by SA books, Its very infomative, and that, along with your post, has convinced me to got mech roller. definently not hyd roller. The added vavle train weight, and cost of a retro fit kit (i dont need a retro fit kit for a mech roller, right?) theres just no reason to not go mech. roller.

The book said that if everything is set up right, you dont need to even check the lash but every 5000 miles, which seems a little much to me, i would still be checking it more often than that, but thats alot less than what i thought (every couple days or hard driving)

So, final questions

I wont need a retro-fit-kit for a mech. roller, right?

just a bumbstop, a dizzy gear, and roller lifters/cam. Right?

Thanks a ton man, this has been frustrating me for a while 

One thing you need to be careful with on small displacement mills (which are running fairly high compression) is the valve/piston clearance.  I don't recall you mentioning the compression ratio and/or piston dome height.  Net, ensure you take into consideration the lift and duration of the cam as you select one to fit your combo. 

You don't want to invest in a high dollar roller only to learn later that it won't work. 

Good luck.

Hey Harrison!

Your gettin' that 302 together aren't you!  Man you gotta keep MR updated on this project. 

I'm knee deep in the Elky's 383 right now myself.

Let me know when you are back.  I gotta see this Z!

Phil