Optimum setup for 302 heads

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68cuda

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What would be the optimum set up (amount of porting, valve sizes, and intake config) for a pair of 302 heads on a 318 running zero decked KB167 pistons at approx. 10:1, with stock stroke, and a 268/276 camshaft for a street cruiser with 2000-2200 stall converter, 904 low gear set and 3.23 pumpkin?

I have a Performer intake now and an Edelbrock 1407 600cfm carb. My understanding, from reading the small block threads, is that these will work well on the low end with the above but limit my high end rpm.

If I stay with the 302's, what kind of porting, size valves, type of intake and size carb would give the best overall high and low rpm performance???

Thanks!
 
I would talk to a head port that bracket races a 318. Speak with BJR Racing. Do a search with his screen name.
 
he says the stock valves are fine also but if you decide to go against it i have some 360 heads for sale
 
I know what I would do. 360 valves installed in a bowl ported head. Done.
 
I recently installed 302s on my 318, port matched to Performer intake and mild runner and bowl work. I'm running stock pistons though. Being you're running zero deck 167s and 10:1, I wonder if magnum heads might serve you better and offer more performance though. You could probably take advantage of larger runners and the 1.6 rocker advantage over the 302s 1.5 opening.
 
Thanks for the replies. The reason I'm posting is because of reading some of BJR's posts. I don't want to over valve the 302's if it would actually hurt performance since I'm building a cruiser street engine.

I have Comp Cams Camquest 6 software (engine dyno for dummies ;-) and am using BJR's head flow figures for ported 302's with stock valves. The flow he obtained at 0.2-0.4 is outstanding.

Ported 302, 1.78 intake, 136 cc runner:
0.1 0,2 0.3 0.4 0.5 0.6
89 164 216 232 231 231

I also read the thread on Lunati VooDoo cams and I'm planning on using their 60403 grind instead of one from Comp Cams. That combo with the Edelbrock Performer and 600 cfm carb, according to the software, will get me over the 400hp mark. Since i already have the intake and carb, and am shooting for 400hp, this sounded perfect.

I'm asking the group for a sanity check because I know you guys have more advanced dyno software and more experience spec'ing and building engines.

Any more input is welcome. I'll also shoot BJR a PM
 
you should just follow the hot rod build
were they used 302 heads and 10-1 compression for like 406 hp
 
Those numbers are preety good for the head and should work very well on the teen.

Run it by BJR. He'll adjust it for you if there be a need.
 
My choice has been 302s, 1.88 intake, 1.60 exh (stock 360 sized), the chamber walls are relieved, bowl work done, a little push rod pinch work, gasket match. Clean up the exhaust. I havn't flowed any. I havent noticed any loss of anything in the low (off idle to 2000rpm) range and response. I've also got a set of early 318 open chambers running the same sizes, but in back cut stainless. Again, no loss of low speed performance. I will also admit, I'm positive I cant port like BJR can. At least not going by flowbench results he's posted.
 
I am building almost the exact same combo for my 65. I have been kicking around the idea of running 1.94/1.60 "nailhead" type valves (or Chevy type valves if ya wanna get picky). The nailhead profile, more than the smaller guide really help low lift flow. Just what you want in a small cube, mild cam engine. It seems to me the overall length of the valves is similar, and retainer/spring combos are an easier mix-and-match with the GM valve, and stainless valves are cheaper that way. This used to be an Old School trick with 340's. I'd love to see some numbers directly comparing the tulip vs. nailhead valves. On a 318 I'm not sure you really gain anything past the 1.88 intake due to valve shrouding, but again I'd love to see a flow comparison between 1.74/1.88/1.60 valves in a 3.940" bore with a similar level of porting.

A few years back Mopar Performance sold these heads ported with 1.88/1.60 (stock 360) valves. In the 90's most of the car mags ran articles using these heads, 9-something to 1 compression and the old 280/.474 cam and usually got well over 350 Hp out of the combo.
 
The nail head does help low lift, as does a larger diameter. But, I think it hurts flow over .300 lift IIRC. May not be as much of a loss on the 302 head because it has a deep throat(keep it clean ;) )and that will help the charge make its way around the head. From what I've seen, most factory type LA heads will lose some flow at mid lift and up using nail heads.
 
Sublime swinger
Thanks for finding that article! I remember reading that and have it printed out around here somewhere. I forgot they had a price break down with part numbers included - a big help.

PM'd Bobby at BJR. It looks like the best valves are 1.78 intake and 1.60 exhaust for what I want to do. Also looks like full porting would be overkill, so I'm asking what other head mods will work best with my planned set up - I'll keep the thread posted.

Moper,
I have a feeling I'm going to end up with a setup real similar to yours - we'll see what Bobby recommends.

C130Chief,
The only nail head numbers I've seen were in a thread here regarding a 915 head. The flow at low lifts (0.1 - 0.3) were lower than standard valves with bowl blend and back cut and the same from 0.4 to 0.6, so I'm not sure if there would be any benefit.

I appreciate all the help fellas.
 
The valves that I like are somewhere in between a tulip and a nail head as this is what the 318/302 heads really like, and a partial undercut on the stems in certian areas of the stem really makes the exhaust flow with either the 1.50 or 1.60 valves, as when both have the same machining on them there's not much difference between them in flow. This way you can keep the chambers small and you don't have to enlarge them for unshrouding the valves. So now just by useing the right valves and with the right mods done to them there's at least 15/20 cfm's, just in the valves. Making the need for larger valves unnecessary. Also the smaller valves will make more velocity than the larger valves will when they make the same flow #'s with less area to get it by. This makes for better response from the engine and better fuel mileage, it will also increase HP and TQ. The reason that I would put the 1.6 on the exhaust is that the street engine seemed to work better than the 1.5 did because of the exhaust restriction of mufflers. There wasn't any difference at the track with the 1.5 or the 1.6 valves and open hedders.
 
The reasoning for using the 1.6 exhaust valves on the street is really interesting - I hadn't considered the muffler restriction factor.

Read through the allpar info. I'm working on thinking "system" so everything works together. So it appears to me that since the optimum valve would be a smaller valve with mods (per BJR), the runners should be kept small in both the head and intake manifold to keep the velocity of the airflow up.

To me that would indicate, since this is going to be a a 268/276 duration cam with 0.477/0.480 lift specs, that regardless of the carb cfm used, something like the Edelbrock Performer or LD4B intake matched to 318 gaskets instead of 360 gaskets would be the best setup.

Man, that goes absolutely contrary to the "bigger is better" attitude that I'm prone to go with!
 
But you only have 318 CI to work with, so the bigger is better thing doesn't apply here.

All my information that I use for figureing out how much head go's on a given engine is:
Piston speed
bore
stroke
rod to stroke ratio
bore to stroke ratio
Intake manifold size and port shape
exhaust diameter and length
camshaft design

so when all this info is gathered and put together I can now figure out the cc's of the runner and how much air it needs to flow and the size of the valve that will work the best.
Then the head choice is made.
 
Also do realize dyno results are not allways worthy for the street and operators and conditions as well as many factors come into play.

The best thing to see is the time slip itself. ;)
 
When choosing a camshaft, and a set of heads, I try to design something that gives the highest and flattest curve on both Tq. and HP from 3000-6000 rpms. This is what makes the car move and ET. If I can make 400 ft lbs. @ 3000 rpm's and hold it to say 5500 rpm's with a peak of say 40-or 50 ft lbs. higher, then 11's or 12's are fairly easy in the 1/4. All engines make the same power as they do torque at 5250 rpm's, so makeing the Tq. high at this rpm also makes the HP high at this rpm.
I guess this is where the stroker guys will be smiling for street use.
 
Spent an hour on the phone with BJR yesterday - I'm a believer. Learned alot and had a great conversation. Looks like I can use a Holley 3310 carb.

Also, earlier I quoted the Lunati VooDoo 60403 268 cam specs incorrectly. Correct lift, etc. are:

Advertised Duration IN/EX: 268/276
Duration @ .050 IN/EX: 226/234
Gross Valve Lift IN/EX: .494"/.513"
LSA / ICL: 110/106
Valve Lash IN/EX: Hyd/Hyd
RPM Range: 1800-6200

Got to get my block, crank and rods up to my local mopar machine shop so I can get the specs needed to get the heads done. Woo hoo!!
 
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