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Cam choice for a 305

Bowtie85

Bowtie85

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Looking for your input on cam choice for a stock 305. Will most likely gasket match heads/intake. Just a regular edelbrock performer.

I was thinking of the comp 4x4 12-231-2 which I have in my 305 headed 350 in the K20. I'm fairly happy with it.

I found a lightly used L79 with matched lifters/double roller chain for a good price.

I'm wondering if that L79 will be to much for this motor?

It's in a stock K10 w/turbo 350, 3:07 gears, 31" tires. I'll post up specs of each shortly.
 
COMP Cams#249-12-231-2
Xtreme 4x4 X4250H Hydraulic Flat Tappet Camshaft
Lift: .432''/.453''
Duration: 250°/258°
Lobe Separation Angle: 111°
RPM Range: 600-4600
$122.99
 
With gearing that high your engine will not be revving high enough to take advantage of a higher lift cam...if anything a off road/towing can that accentuates low end torque and HP would be a better choice....but if your stock cam has worn lobes,(as many 305's did)--anything would feel "better" in comparison..

I dont know the specs of the L79 cam offhand,if its a high lift one you might need stiffer valve springs and possibly longer slotted rocker arms..a "hotter" cam will reduce low end power and torque and make it feel doggy till it winds up over 2800 rpm or so...you'll never reach that rpm on the street much with 3.08 gearing..
 
I believe it is a Elgin grind cam. Looks like a 2200-5200 range.

GM L79 - 350 horse, 327 cam - with matched lifters - part # 3863151 - .447/.447 - 221/221 @ .050 - lobe center line: 114 degrees


Any other suggestions appreciated.
 
Yeah that's what I'm thinking. Haven't really come up with much on google. Some say it will and won't work.
 
Diesel4me is right. By far the biggest mistake I see people make with trucks and 4x4s is over-camming. A high lift cam with an RPM range you never get into that sacrifices low-end torque for high end power is exactly what you don't want in a truck (unless you're building a mud bogger). In order to take advantage of such cams, you need heads with a lot of flow, high stall converters, and gears. What works for a 3300 lb car with 200cc runners and a 3500 stall at the dragstrip doesn't work on a heavy 4x4 with a mostly stock powertrain and economy gears.

The beauty of trucks is that a cam that works well for low-end torque is generally well-behaved and has minimal consequences. I have a Com 254 4x4 cam and have been pleased with it's near stock idle and low-end pull. It's perfect considering the truck never sees much over 3-4K rpm.

A note on the L79-excessive overlap bleeds off compression, so it's really not suitable for lower compression engines. I wouldn't use one in an engine less to 10:1 mechanical, but your mileage may vary.
 
Yeah I know it's usually better to be under than overcammed.

Still on the fence with it. Just thought I'd see what a couple people had to say on here.

Found some good reading on nastyZ28 forum as well FWIW.
 
Paratrooper is right--though a hot cam sounds nice and does a lot to make for better higher RPM power,its not something you want in a truck thats heavy,has higher gearing,and will be used to tow,or crawl along a rocky trail at off idle speeds...

With a hot cam the engine will be too lumpy at idle and lack enough low end torque to be driven smoothly under rough trail conditions,or even in heavy stop and go city traffic,especially if its got a manual tranny or an automatic with a stock stall speed converter....you want just the opposite,one that improves idle,throttle response,and yet still allows it to breath well enough to top out around 4000 to 4500 rpms..

Next to using to "hot" a camshaft,the second most common "mistake" is to put a high rise open plenum intake and a huge 4 barrel carb on an engine thats going to be used at lower rpms most of the time..I found out my '72 K5 with a 350 was MUCH better at crawling off road with the dinky Rochester 2 barrel and intake off a 283 it had on it when I got it (the smaller of the 2GC Rochester carbs GM used on small blocks)...

When I put a Holley intake and a Carter AFB on it,I was pretty dissapointed with its off road ability in comparison..it flooded easily when I "tilted" the truck on rutted paths,and it was "lurchy" and hard to take off smoothly ,and got worse gas mileage--it did go a bit better on the street and higher speeds though..but the small venturi's on the 2 barrel kept the fuel air mixture flowing better at low speeds and it had better take offs from a stop than the 4 barrel did,it always had a bit of a "bog" taking off..it also pinged more with the Carter carb..
 
Yeah seems people like to over carb stuff as well. I see buddies and ppl doing it all the time for some reason :doah:
 
I had a friend who owned a 1968 Olds Delmont 88--had a 455 with a factory 2 bbl carb,and 10.5 to one compression!...turbo 400 transmission..driven like a normal person,the car often got 14-16 mpg..

That car could lay 300+ feet of posi uphill on a steep street that was a 45 degree angle and was almost 1/2 a mile long,in the town he lived in!..

Several of our friends had muscle cars,one had a '70 455 Buick GS ,another had a 72 Charger with a 440 ,with three two barrels,another had a '67 Olds Cutlass with a 425...they all had hot cams,huge carbs ,etc...none of them could pull that hill and burn posi like that!..and the '68 Olds my friend had,had a 12 bolt posi in it with 3.23's,the other cars all had 4.11's...some of them could lay more rubber,but not posi!..shows "leaner is meaner" often,and thats probably why GM used such small primaries on the Q-jets..better economy and better air/fuel control at lower speeds...
 
There's no reason to use early 60s cam tech with all the modern options that that are lightyears ahead. What about a vortec 350 roller cam?
 
Main reason is a budget for it.

It's also not a roller block, and I don't feel like going there with a 305.
The truck has a well worn knocking 350 in it now that I wouldn't mind rebuilding and doing a roller cam retrofit over time.


Not sure if this deal with the L79 cam will pan out.

I will otherwise prob toss that comp 4x4 cam I listed first in it.
 
It's a 305 in a heavy truck with tall gears. It won't be happy unless you stick in the mildest cam you can find. For truck use, I think the factory actually did good with the cam, the halfway decent low end grunt (for it's size) is the only thing good about those motors. I would not want to take away from that.
 
I think you'll be a lot happier with a dedicated 4x4 type cam. If you want a healthy lope or that "cammy" sound, they won't do it though. As I said, I stepped up to the 254 (.447/.462) and it still idles like stock, very driveable.

If driveability is a concern, I'm betting you won't be happy with that L79. The only thing the 305 has going for it in power is the higher compression heads to boost low end, which that cam will negatively impact. The factory engine that came in was a 350 with 11:1 compression sitting in a Corvette, Chevy II or Chevelle chassis. Basically, it's pretty much the opposite setup you have now. Nonetheless, best of luck whichever way you decide to go! If you don't like it, it's maybe a day's work to change it, lol.
 
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