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Vortec for older 350?

14K views 9 replies 9 participants last post by  gt2betubbed 
#1 ·
I have searched for the answers to the following questions but have found no answers. Please help if you can.

I am running a SBC 350 and wish to improve it's performance. I currently have a mild cam (214/224, .442/.465) that is still uninstalled. I would like to run a slightly hotter cam but don't think it would work well due to a low compression ratio (8.4:1). I also have headers, a 650 Holley double pumper, and a Weiand Xcelerator intake installed. The HEI has also been recurved and had an adjustable vacuum advance intalled and locked out at 12 deg. advance. The pickup weighs 3380 pounds without a driver and has a 3.73 limited slip rear. Transmission is a 350 with a shift kit. Torque converter is stock. This is a semi-daily driver.

I realize that Vortec heads may not be the best but it is a matter of economics and they were given to me by a friend. I would like to install them to increase the compression ratio due to the smaller combustion chamber. These heads came from a late model 350 and are the 906 castings. I have several questions.

1. I have read that you can use a non-vortec intake if you slot the bolt holes. Is this true?

2. Is the Vortec roller cam setup worth using? It seems to be priced right whenever I see them for sale.

3. Where can I find duration, lift, etc. numbers for the Vortec roller cam?

4. If the cam is too mild, can I use another roller cam with the factory Vortec roller lifters?

Thanks for your help.
 
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#2 ·
I'll try questions 1 and 4.
Q1: No, the Vortec heads only have four bolts on each side. I would be "uneasy" trying to modify another manifold and not have leaks.
Q4: As long as the roller lifters are not damaged they should work with any roller cam.
 
#3 ·
I bought the scoggin-dickey vortec head kit for my sons .030 over 350(1972) put in the Crane Energizer hyd. cam (.480 lift), we put this in his 81 Chevy p/u and it runs pretty good for almost 4000 lbs.,it has run a best of 14.36 with zero traction,2.20+ 60ft. times with its 3.42 pegleg rearend, with the 4.11 I imagine we'll see mid 13's. The head kit consists of heads,intake,all the gaskets and bolts you need to do the job. I don't think the X cellerator intake is helping you out any either.
 
#4 ·
I agree the intake is not the right one for my current application. I intend to run a Performer RPM Airgap in the future. The Xcelerator is just what I had on hand.

I am looking for more compression for the power it creates and the better cam I can run. I believe I should get an increase of somewhere around 1.0-1.25 compression points over my 75cc heads.

A little gasket matching and polishing can't hurt.

I intend to go with a roller cam if possible. Already have the Vortec roller lifters and a set of roller rocker arms.

Now if I can just find a way for it to hook up! But guess I will post that question in another forum.
 
#5 ·
just finished a 350 with the 906 vortec heads. was reading an artical in H/R or C/C on porting vortec heads. in a side bar was a dyno test on a 350 mule motor, witha comp cams 230/236 @ .050and .490 lift the mule made 436 hp with a vortec agap and a750 carb. with the heads ported it made 466 hp. well i decided i couldn't see 30 hp so i am in the process of putting some miles on my eng. it sure feels good .all for an out lay of aprox 1100. 00. this included a clone of the edelbrock vtech air gap at 150 in my hand. just a thought.
 
#6 ·
You should refer your cam and roller questions to the cam manufacturers, however, if it is a used lifter, they usually do not recommend using the lifter with other than its original cam and it should be lobe matched as before.

The Vortec is a 64cc head, maybe you knew that, and the best way to change compression is to buy pistons, they are not that expensive.
 
#7 ·
I would suggest using thin head gaskets and going with the edelbrock air gap intake. also GM performance parts makes a few roller cam kits to go with your motor if it is an 86 or newer. roller lifters are reuseable and roller cams do not require break in. Did the heads come with rockers? because the vortech heads require self aligning rockers. good luck!
 
#9 ·
"For example GM's stock Vortec cam is 202 and 207 on the intake and exhaust with .41 and .424 lift on a 115 degree LCA". That's an excerpt from Sallee Chevrolet's discussion board. The LT1 roller cam has similar duration & more lift (.447/.459). I don't know if these cams have a fuel pump lobe, though. The ZZ4 cam has a fuel pump lobe & 208*/221* duration, but its lift requires machining the valve guide boss for clearance. These will work with the factory roller lifters, but you might want to upgrade the valve springs.
 
#10 ·
Just my .02, but I wouldn't recommend re-using the roller lifters. Since the cam you have now seems to be a little more aggresive than the stocks, I would just get a set that matches with it. From the sounds of it, your truck sees the track often, and that would just be a weak point.
 
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