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cam for 350vortec
- Thread starter 79wheeler
- Start date
LongIslander26
1/2 ton status
Cam choice
Well, it depends on a lot of things. What type of driving is the vehicle going to see the most of? Highway or around town? Is it a roller cam motor, or flat tappets? What kind of tranny do you have? What rearend gears are in it?
Are you looking for rockcrawling grunt, or blasting though a mudhole? You need to be honest with yourself too. If you want it to be the ultimate Hi-Po off road machine, but you only go off road say, once every other month, and have to drive it to work everyday, you're probably going to hate driving to work. What RPM range does the engine see the most?
Well, it depends on a lot of things. What type of driving is the vehicle going to see the most of? Highway or around town? Is it a roller cam motor, or flat tappets? What kind of tranny do you have? What rearend gears are in it?
Are you looking for rockcrawling grunt, or blasting though a mudhole? You need to be honest with yourself too. If you want it to be the ultimate Hi-Po off road machine, but you only go off road say, once every other month, and have to drive it to work everyday, you're probably going to hate driving to work. What RPM range does the engine see the most?
hi, well it's my toy, but it will see the highway and pulling my bass boat. It's not going to be an every day driver but some thing for the weeked. It has a 4 speed ,33 on with a 4' lift ,gears not sure on yet. have not had it for long.. not a crawler but all around wheeler... THX.... 
LongIslander26
1/2 ton status
Cam choice
With the Vortec heads you are limited to about 0.450" of lift, unless you have the spring seats machined. Assuming the engine is a roller cam, I would look into a cam that gives you the most lift you can get, without going over about 215 degrees of duration at 0.050. Any higher than that and your getting into a "Midrange" cam that you really don't need with an overdrive tranny. You want alot of bottom end torque to get you going quickly off the line with those big tires, and towing your boat. With an overdrive tranny the engine is rarely going to to see the high side of 3500 rpm's, and cruise at around 2 grand. I don't know what the emissions laws are where you live, but you want headers and a free flowing exhaust. Dual setups work well on these trucks with a 2 1/2 in pipe. The compression ratio in that motor is about 9.1/1 stock. That's plenty for a low duration cam to still run on pump gas. The GM intakes are pretty good, and there's really no need to change it. Th GM Vortec intake manifold gaskets are pretty flimsy, and fail pretty quickly. Use a good aftermarket brand like Fel-Pro or Rol. If you like, E-mail me through this site, and I can send you some Dyno-sim charts with a few recommended cams in them, and you can see where the power will be. Or you can call the helpline of the cam manufacturer you want to deal with, and have them recommend something. I'm partial to Comp Cams myself, but I've gotten good results with other manufacturers depending on the application.
With the Vortec heads you are limited to about 0.450" of lift, unless you have the spring seats machined. Assuming the engine is a roller cam, I would look into a cam that gives you the most lift you can get, without going over about 215 degrees of duration at 0.050. Any higher than that and your getting into a "Midrange" cam that you really don't need with an overdrive tranny. You want alot of bottom end torque to get you going quickly off the line with those big tires, and towing your boat. With an overdrive tranny the engine is rarely going to to see the high side of 3500 rpm's, and cruise at around 2 grand. I don't know what the emissions laws are where you live, but you want headers and a free flowing exhaust. Dual setups work well on these trucks with a 2 1/2 in pipe. The compression ratio in that motor is about 9.1/1 stock. That's plenty for a low duration cam to still run on pump gas. The GM intakes are pretty good, and there's really no need to change it. Th GM Vortec intake manifold gaskets are pretty flimsy, and fail pretty quickly. Use a good aftermarket brand like Fel-Pro or Rol. If you like, E-mail me through this site, and I can send you some Dyno-sim charts with a few recommended cams in them, and you can see where the power will be. Or you can call the helpline of the cam manufacturer you want to deal with, and have them recommend something. I'm partial to Comp Cams myself, but I've gotten good results with other manufacturers depending on the application.
hp charts would be great !!! It is a 4 barell carb too.. Thanks alot.... 
Mad-Dog
1/2 ton status
I'm going to add my 2 cents and and recommend the Comp HE260H which is a single-pattern hydraulic grind designed for 4wd and towing with a 350cid engine,it has a good idle, strong midrange and specs out at 212/212-260/260-.440/.440" and 110 lsa.
I believe this would pull the boat nicely and give him a kick in the pants on the back roads....it is also compatible with stock valve springs.
I believe this would pull the boat nicely and give him a kick in the pants on the back roads....it is also compatible with stock valve springs.
LongIslander26
1/2 ton status
Ahhh, a MANUAL Tranny!
Ok, so the tranny is a manual. That changes things, since I'm assuming you have a 1:1 final drive ratio out of the tranny, you may want to venture into the low- midrange cams. Is it possible for me to e-mail on this site, or do you have a yahoo messenger name? Mine is the same as my username here. In any event, you're not going to want a cam much higher than 220 degrees @ .050. What year did you say this was?
Ok, so the tranny is a manual. That changes things, since I'm assuming you have a 1:1 final drive ratio out of the tranny, you may want to venture into the low- midrange cams. Is it possible for me to e-mail on this site, or do you have a yahoo messenger name? Mine is the same as my username here. In any event, you're not going to want a cam much higher than 220 degrees @ .050. What year did you say this was?
Sorry, I didn't clarify hehehe ... it's a 79 special edition blazer my e-mail is [email protected] anything would be great...thanks for the help
LongIslander26
1/2 ton status
Cam choice
I agree with mad-dog. I was going to recommend the HR 260 if he had a roller cam and the heads would take the lift. I'll print up a dyno sheet and e-mail it to you. My e-mail will be on the e-mail I send you. Cool beans
I agree with mad-dog. I was going to recommend the HR 260 if he had a roller cam and the heads would take the lift. I'll print up a dyno sheet and e-mail it to you. My e-mail will be on the e-mail I send you. Cool beans
LongIslander26
1/2 ton status
you have mail
Check your mailbox, Bro.
Check your mailbox, Bro.
LongIslander26
1/2 ton status
Well??
Did it go through? Did you get it?
Did it go through? Did you get it?
Any cam you decide to go with, call them and make SURE that the Vortec springs make enough seat pressure to work with the cam.
Roller cams are different, but the stock Vortec (which was roller) cam is VERY mild, so even a fairly aggressive hydraulic cam I'd suspect might have spring pressure problems.
Just some speculation, but along with the lift issue, this is something I had to work around.
Roller cams are different, but the stock Vortec (which was roller) cam is VERY mild, so even a fairly aggressive hydraulic cam I'd suspect might have spring pressure problems.
Just some speculation, but along with the lift issue, this is something I had to work around.
moturbopar
1/2 ton status
Hi, I have a vortec 350 HO 330hp in my blazer. The cam that comes with this motor is great it a mild hydrolic the specs are at .050 is 212in 222ext .435 lift in and .460 ext on a 112.5. Car craft had an article on this motor. With this cam performer rpm holley 750 and 1 5/8" headers the engine made 371hp and 408ftlb it! My truck idles with 17.5 in of vacuum and has smooth idle and has pleanty of power even though i have the fastory exhaust manifold on it for now.
Where in AZ are you located?
Thanks Shawn
Where in AZ are you located?
Thanks Shawn
Hey all, Had some stuff to do... I live in the north valley.you buy that 350motor crate sounds sweet!!! What Kind of low end power do u have? .Islander , the mail was just all numbers mabey you could try it agin Thx etheir way...
.Islander , the mail was just all numbers mabey you could try it agin Thx etheir way...LongIslander26
1/2 ton status
Crate motor
I have the same motor with the same cam in my 79 Jimmy. It ran like a raped ape when I lived in Mesa, but up here at 6500 feet of altitude it's lacking a bit of power. I'm actually considering stroking it to 383, and putting a slightly smaller cam in it. (The roller version of the one I recommended to you). Being carbureted is hurting it too I think. I'll try something else to get you that sheet. Hang loose for a minute. "Special edition" was probably just a dealer installed option package that Chevy gave its blessing to.
I have the same motor with the same cam in my 79 Jimmy. It ran like a raped ape when I lived in Mesa, but up here at 6500 feet of altitude it's lacking a bit of power. I'm actually considering stroking it to 383, and putting a slightly smaller cam in it. (The roller version of the one I recommended to you). Being carbureted is hurting it too I think. I'll try something else to get you that sheet. Hang loose for a minute. "Special edition" was probably just a dealer installed option package that Chevy gave its blessing to.
LongIslander26
1/2 ton status
Dyno sheet
Well, I could fax it to you, if that's possible, or I could just give you the highlights.
300hp @ 4500 rpm
387 lb/ft @ 3500 rpm
380+ lb/ft from 2000 - 3500 rpm.
Nice flat torque curve from idle to almost 4 grand.
Whatever cam you go with, get the springs that are meant for the cam.
Well, I could fax it to you, if that's possible, or I could just give you the highlights.
300hp @ 4500 rpm
387 lb/ft @ 3500 rpm
380+ lb/ft from 2000 - 3500 rpm.
Nice flat torque curve from idle to almost 4 grand.
Whatever cam you go with, get the springs that are meant for the cam.
beater_k20
Banned
79wheeler said:
pics? Honda heads will not physically bolt to a GM SBC block, im curious to see how you did it.
V-O-R-T-E-C
LongIslander26
1/2 ton status
Truck pics.
I'll snap a few and post them here. It ain't nothing special paint wise, but it's a good solid AZ truck. It was in alot better shape when I bought from the old lady who was the original owner in Tempe, I've taken it out and womped the crap out of it a time or 2 (Blew the tranny up once as well). I'll get them snapped off and posted here in a day or 2.
I'll snap a few and post them here. It ain't nothing special paint wise, but it's a good solid AZ truck. It was in alot better shape when I bought from the old lady who was the original owner in Tempe, I've taken it out and womped the crap out of it a time or 2 (Blew the tranny up once as well). I'll get them snapped off and posted here in a day or 2.
