i'm tearing my 350 down to the cam. as far as i know it was rebuilt to stock specs, so my question is what components should i use as replacements for the best off idle - mid range torque? i'm talkin cam, lifters, timing chain or gears, intake, carb and also a good stock head that will all work well together. my set up is 350, sm 465, np 205, 14 bolt and dana 60 with 538 gears, 40" ground hawgs all in a 1973 chevy short box. thanx guys!!  

Years ago my favorite cam in a 4x4 was a Competition Cams H260. Not bad right off a idle and pulled strongly from about 1500 to 5000 in a engine with 9 to 1 CR. Would not go any warmer than that and if you want even better low end power and if you have lower CR you might try a H252 or so as it is stronger off a idle and pulls well to about 4500 RPM or so. As a rule of thumb, the higher your CR the warmer the cam you can run without taking to big of hit on lower RPM torque. One more thing, if low and mid range power is your goal, limit carb to a 550 or less and use a dual plane intake manifold.  

thanx a bunch snoman!! i had an idea about which cam to run and you just backed that up. i might have trouble finding a 550cfm carb, how about a 600cfm edelbrock and maybe jet it down? as for intake i'm lookin into edelbrock performer series not the performer rpm tho. what do you think?  

I DID A MILD REBUILD ON MY 350 USING A GM PERFORMANCE CAM
#12353917-DUR@ I-204/E-214 AND MAX LIFT I-420/E-442 FOR 8.0CR-9.5CR AND HAD AN EDELBROCK PERFORMER SERIES INTAKE AND USE THE EDELBROCK 600 ELECTRIC CHOKE #1406. HAD GM PERFORMANCE HIGH VOLUME OIL PUMP,HEADERS,FLOWMASTER,HEI...AND I HAD GREAT POWER LOW END AND MID RANGE ALL IN MY 74 C10. I FELT THAT THIS WAS A GOOD BUILD AND HAD EXCELLENT RELIABILITY,FOR THE CLOSE TO 2 YRS I HAD IT AFTER I REBUILT IT I NEVER HAD A PROBLEM.  

chopperfreak2k1:
thanx a bunch snoman!! i had an idea about which cam to run and you just backed that up. i might have trouble finding a 550cfm carb, how about a 600cfm edelbrock and maybe jet it down? as for intake i'm lookin into edelbrock performer series not the performer rpm tho. what do you think?

If you are not planning to take it past 5000 RPM much even a 500 CFM will work fine. The reason it seems that I am hung up on small carbs is that big 4x4 need strong low end and mid range response and a smaller carb has higher air velocities in bores at all RPM's and this leads to better fuel/air mixing and response. Ideally you want a carb that maxes out at you desired peak RPM that you plan to use. A 500 CFM carb will reach rated flow on a 350 at about 5500 RPM. Also that rated flow on a 4bbl is at 1.5 inches of mercury pressure drop. (about.7 PSI)and it will flow more at a slight greater drop. (2bbl's are rated at 3 inches or about 1.4 PSI of drop)  

well you are making perfect sense to me snoman. although you did lose me when you went into the mercury pressure. lol ( i dont know that much ) i would like to be able to turn around 5000 rpm but definetely no more cuz i figure if i keep the rpm range low then my motor SHOULD be a little more reliable, right? also i looked into the comp cams 260H and the 252H. it looks like i may want the 260H over the 252H cuz in its description it states the 260H has exceptional power for pick-ups and tow vehicles. so thanx for the advice on the cam. other then that your saying look into a 500cfm carb and i can go ahead and use the edelbrock performer intake? so my cam would come on from 1,200- 5,200rpm and the edelbrock performer intake would support it from off idle - 5,500 rpm which will work well with a 500 cfm edelbrock carb. does all this look good to you?  

I have been sitting here thinking on this and you ?might" want to go with 252. If it was a automatic, I would say use 260 for sure but as I recall now thinking about it, while I liked my 260's a lot, they were with manuals and they did not pull at 1000 RPM like stock cam did. The came on about 1500. Not that they were gutless at 1000 RPM but not like stock cam. Since you have a manual and if when you drive you like to lug it down to 1000 or less at times, you might be happier with 252. I hope I did not muddy the water for you. BTW, the inches of mercury thing is that standard pressure at sealevel is 29.92 inches (about 14.7 PSI) This is where the inches of mercury rating comes from and I converted it to approx PSI pressure drop.  

alright snoman i'm following ya, but if i'm gonna consider the 252 then let me ask you this, what do you think about the edelbrock performer cam? the 252 and edelbrock compare like this-
cam    adv dur    dur@.050    lift    lobe sep    rpm
252    252-252    206-206    425-425   110    800-4800
edel   278-288    204-214    420-442   112   800-5500
i ask cuz i'm not real sure how the numbers effect real life performance. but these are the two cams i'm considering right now (that might change in 15 mins) lol!! do you still think i should go with the 252? i'm only conserned with off road performance as my truck will see very limited on road use.  

kiethpapa, the edelbrock performer cam sounds identidal to the gm cam you used. i just wish i knew my CR.  

The whole "thing" behind a competition cam from the start is that it delivers more effective flow within the same duration. They use a asymmetrical lift profile which opens valves quickly, keeps them at peak lifts longer and closes them quickly too which mean more total flow. (asymmetrical lifts do not play well at 7000 RPM but that is not a issue here) You get the best of both worlds in that you get more flow and HP but also a shorter duration for more effective CR and less overlap. When you compare your cams you will see that the second one thought advertised as a 278/288 has LESS time as .050 and above than 252 (the reason they use  this .050 is because this is the "std" lift at which effective flow is said to take place) On the exhaust, even though it has on paper 36 more degrees of lift it only has 8 more degrees at .050 and above. Also, if profile durations were studied at .1 lift and above one might find that 252 has same or greater flow time in this area. The extra exhaust lift at peak does nothing for low and midrange torque and is done to try to "extend" the cam a bit to a higher RPM range at a slight loss of lower RPM torque. On the lobe centers, 110 is more favorable for low and mid RPM torque and response. Many years ago I had a 72 GMC 3/4 ton 4x4 I built up. I got truck when it was a few years old and it had a SM465 with spicer 4.10 drive axles (D44HD/D60) and even factory dual fuel tanks and split rims as well. After playing with it for a few years I built engine up a bit. 72 was last year for higher compression 350 4bbl's and it ran well stock and had strong lower RPM torque. (never had to really use low range in this truck) Used to take it hunting and muddy hill climbing a lot and 2nd gear foot to floor worked well with stock cam for a combo of tires speed and ground speed and engine torque was such that it would not fall flat if grip got good and it would not over speed engine WOT on slick climbs because stock cam ran out of breath. When I went to 260 in that truck things changed a bit, good and bad. You needed to get RPM a bit higher before you could step all the way into it and have it respond properly (would not lug as low) and on hill climbs I had to back out of it a bit at times because RPM would climb more and get higher than I liked (above 5000) because cam had more top end pull. If I had it to do over, I would have like to have tried a 252 in that truck. Everybody has their own style driving but myself I like strong low and mid RPM torque and will trade some high RPM power for it. The 465 has a wide ratio range so there is a lot of RPM drop on shift and you do not want to have to wind it tight it gear just to get into a good torque range in next gear. (this is why I like low end torque) If you ever had the chance to drive a truck with a old pre-emission 292 inline six, those engines were stump pullers. Only about 170 HP but torque peaked at 1600 RPM (and would pull HARD from idle speed too)and power peaked well before 4000 RPM and they were wicked with a granny tranny.  Sorry if I got carried away here. Time to get off soap box.  

yeah chopper it does...the only reason i went w/gm perf. cam was i worked for a chevy dealer and got an awesome deal over the edlebrock...but i had great power off idle to 5000rpm...im not as good *** like sno but i had good luck w/both gm perf.and edelbrock intake/carb set up,and the engine i rebuilt was 9.0/1 CR crate replacement 350 i got from the dealer too for 100$(core) that somebody turned in w/30K miles on it. i tore into it and found nothing wrong with it.  

well snoman i really appreciate you taking so much time to help me out here, you too keith. i know just what you mean snoman about the wide range sm 465 and you are making perfect sense to me as to why to run the 252. in fact you totally convinced me to go with the 252, but i have one more question. (don't i always?) comp cams also has a 240H cam, should i consider this at all or is it a bit much?
adv. dur.    dur@.050    lift    lobe sep.    rpm range
240-248      192-200    395-395   108        600-4600

i know i'm probably gettin to be a pain in the butt, but i wanna make darn sure i get the right parts for this build cuz i'm on such a tight budget, also your teaching me ALOT. i think the 240H cam might be for smaller displacement motors but i wanted to ask you and get your opinion. and please stay on your "soapbox" all you want!! as long as you wanna talk i'm happy to listen and learn!  

Never tried a H240. My guess is that it would play well in a 305 or such. In a 350 it would likely have tractor engine like qualities with excellent low RPM torque. I still think H252 is better here because duration is still short and it has more lift than 240 which mean more mid RPM power (3000 to 4500 RPM) than 240. I feel that a 252 would give you good low end torque with a strong mid range when you want to really put your foot in it and a good compromise between a 240's low end torque and a 260's mid to upper RPM power. If you were building a truck to putt around the farm with and never really get into it (WOT and crank it a bit) I would go with 240. Also, if you never plan to take you truck above 4000 RPM with any power expectations the 240 would work for you too. But since this is a lifted truck with big tires and nice gears and you are going to get into it from time to time I would go with 252 if it was my nickle. Another somewhat related tip, exhaust, you do not want it big and open if you want max low RPM power. Most tend to think that "logic" tells them that dump exhaust fast for max power at all RPM's but it does not work that way. A IC engine is driven by expanding gasses not explosions and the piston is driven down by it which turns crank. The more it is expanded before it is vented, the more lower RPM torque that is captured from it. Vent it too soon or too quickly at lower RPMs and torque suffers (this is why cam's can have such a effect on lower RPM torque) As RPM increases there is less time to get gas out of cylinder so more duration and lead is needed for good top end power. (some new engines are starting to use variable duration/timing of cams to get best of both worlds)If make low RPM torque is your goal here and with noisy mufflers, I would suggest a set of 2 inch duals with a cross over. Many over tube exhaust and actually hurt lower RPM power and efficiency. Headers can help mid range and top end but will hurt you at low RPM's too. If you are planning to run a wide open exhaust then maybe I would do a 240 but otherwise I would do a 252. Sorry if I ramble on here but many focus on max sound and RPM while I tend to focus on lower and mid RPM power where your engine spends most of it time normally. I was never a max RPM guy all the time. The added benefit of strong lower RPM torque is improved engine efficiency too which means improved MPG which is never bad at todays fuel prices.  Oh, one las tip here, buy a offset cam drive gear that lets you run cam at TDC or 4 degrees plus or minus timing in relation the crank shaft. This give you option of fin tuning cams power curve to your needs. Advancing the cam will increase lower RPM response a bit while reducing top end a bit and retarding it will reduce lower RPM power while increasing top end a bit. (this way you can tweak the cam a bit later if you want too) ALso do plan to run 89 octane or better in this engine as it will allow more advance of spark for best low and mid range power that 87 will.  Hope I did not confuse you more here.  

no sir you did not confuse me, and i thank you for taking so much of your time to help me understand what to do and why. i did not know how timing advance and retard effected torque at a given rpm and now i do.right now i do have an open exhaust but i will take your advice and as soon as i can i will install the 2" with cross over. i do have headers but i guess i gotta live with that cuz i don't have another set of exhaust manifolds. thanx for shining some light on the 240 for me, i will go with the 252. is there a timing chain and gear set you might recommend? also what do you think of timing gears and their effect on engine harmonics? is there a distributer i should look at or will my stock HEI do the job? thanx as always snoman!!!  

I have not bought a timing gear set for a long time. Competition Cams makes a good set. Try Jeg's or the like for a timing chain set with the adjustable cam gear I mentioned above. Headers will not hurt you much of you close up exhaust otherwise. You might give some thought to retroing to a older style dual point distributor. They are highly customizable for timing curves. Most HEI system have smog curves in them. Just a thought anyway.