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Old 09-05-2011, 10:43 PM
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My 305 Vortec TPI Street Build

Got tons of pics, and even more questions!

What I'm working with:

350 Fullsize Truck Longblock
906 Vortec Heads
SDPC Vortec TPI Base
Stock Plenum/Runners/TB
Factory Dual snorkel CAI
24 ilb LT1 injectors

What I'm wondering about:

Finding the right cam for the build
Trying to work with the stock lift I can get out of the Vortec heads
Finding the right combination to give me good HP and TQ, and enough vacuum to be able to run accessories

Well heres some of my progress guys:

Got the V6 out




Heres my 350:



Still cleaning it up





So I've been reading a lot about cams lately, and this 350 Block isnt a roller block, but I'm going to convert it to be able to have the most efficient valvetrain possible and avoid the headaches of flat tappet. Some of the guys on thirdgen.org say that 218/224 duration is great for a TPI, but when I search for a cam with that duration, all I get it .550+ lift, and I don't want to run that much because of I'll have to completely rebuild the Vortecs.

And its almost impossible to find good info on just how much lift you can run on stock L31 906 Vortec heads, some say as low as .420, and some say as high as .495, so I'm almost at a complete loss to find a good cam for my build.

Does anyone have any suggestions? I tried CamQuest and I got a few good cams, but I'm not sure about them.

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Old 09-05-2011, 10:57 PM
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Far as I know the safe lift for a Vortec is .450. But I also got bad news. If your going to convert a flat tappet to a roller cam your going to spend a ton of money. The next issue is, the valve springs for a roller cam have to be used with springs for a roller, and even the smallest of roller cams will require new springs and they are larger than the stock spring pocket on the heads so the heads will have to come apart anyway. To get the guides clearanced on Vortec heads only costs around $50 bucks and to get the spring seats opened don`t cost that much either. If the heads need guides is when it gets expensive. I wouldn`t waste time or money on a flat tappet block. To covert it over to a roller costs around $800 clams.
Instead I would go find a Vortec 350 that comes with a factory roller cam, you can reuse the roller tappets that come in it so you don`t have to buy a $300 buck set of roller tappets. You didn`t say what computer system you have, but in almost any GM injection, the computer has to be changed anytime you change the cam. The cam of .218/.224 would not work with a stock computer system.
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Old 09-05-2011, 11:12 PM
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I will be using a 1227165 computer, and I know I will have to tune, thats fine. I shouldn't have to change the springs and retainers of the heads or anything because the Vortecs are meant to be used with a roller valvetrain. And if I can only do .450 lift safely, then thats fine.

And what else do I need to convert my block to roller valvetrain other than lifters with vertical link bars, and a retrofit cam? There seems to be a problem with finding engines in my area, because I had to drive almost three hours to even find a 350 for sale. And I know I won't be able to find a roller 350 very easily, and I'm not going to go buy yet another engine(Have a 305 laying around too....) when I have a perfectly good one here, that only needs to be retrofitted to work right. So I'm gonna have to make it work.

Vertical link bar lifters are only $310 for a set on Summit, and I need a new cam anyway, so I'm not going to even factor that into the price to convert the block.
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Old 09-06-2011, 11:21 AM
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Just realized I accidentally typed 305 instead of 350, haha I'm building a 350
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Old 09-06-2011, 01:08 PM
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My vortecs have the GMP v6 beehive springs , viton seal, and little v6 retainer. This extends the lift to about .470-480 and , the gain comes at the retainer to seal area. My performer cam safely fit that has .442 lift on exhaust side. Comonly mill the 67cc head .030" to 64cc for quench .

Vortec heads and intake are worth the 3-400 . The heads go fast, check the lists and bring a breaker bar.

They have a better mid range than the 58 cc 416, and noticeable sprint added at the top end. If the compression is good, the low end is superb.

Porting, all bets are off.
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Old 09-06-2011, 01:30 PM
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Already got the heads, brand new never used, pulled off a crate engine. The guy ended up getting E-tecs instead.

Now that I'm looking at my cam choices on Summit for a retro fit, it looks like theres nothing that would run within the limits the Vortecs can handle stock, so I guess I'm going to be getting new springs and retainers anyways. I was thinking about an LT4 hotcam before, so maybe I'll run something close to it and just pay the extra $160 or so to get new springs and retainers.
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Old 09-06-2011, 04:13 PM
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Okay. First of all, Vortec heads could care less if it's a flat cam or roller cam actuating the pushrods. For that matter, it doesn't matter what head it is.
You should be contacting Myron Cottrell at TPI Specialties. He has been working on TPI engines since they were introduced and has developed many parts and well as cam grinds to make good power. Do a Google search or forum search here on the "beehive springs". They will make your Vortec's able to handle the lift of the cam that Myron recommends.
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Old 09-06-2011, 06:53 PM
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I know the only thing that should matter about the Vortecs is that I have springs that will handle the amount of lift that I want to run, not what kind of valvetrain I'm running. When I was planning on running the LT4 hotcam I was going to use LS6 valve springs because a lot of people said they work good like the BeeHive springs do. And the retainers I have would work with LS6 or other springs or do I need to get new ones?

And I'll see if I can give him a call sometime to see what he can recommend. Thanks.
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Old 09-06-2011, 07:06 PM
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Quote:
Originally Posted by spinn
My vortecs have the GMP v6 beehive springs , viton seal, and little v6 retainer. This extends the lift to about .470-480 and , the gain comes at the retainer to seal area. My performer cam safely fit that has .442 lift on exhaust side. Comonly mill the 67cc head .030" to 64cc for quench .

Vortec heads and intake are worth the 3-400 . The heads go fast, check the lists and bring a breaker bar.

They have a better mid range than the 58 cc 416, and noticeable sprint added at the top end. If the compression is good, the low end is superb.

Porting, all bets are off.

What about 416's now? I have a set off my 305, and I hear they're becoming popular P&P heads for 350's because you can easily get high CR's out of them. I guess they can't be anywhere near as good as a set of 906 Vortecs.
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Old 09-06-2011, 09:14 PM
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The replaced 145hp 305 gm heads were 601 58 cc. The stock ports were bent in a corner, not a full rectangle.

Vortec heads are noticeably different, the tiny retainer and gm beehives are stable at 5500. Use a gov kit to calibrate the full throttle shifts to 4800-5000. Take advantage of it.
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Last edited by spinn; 09-06-2011 at 09:39 PM.
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Old 09-06-2011, 11:20 PM
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The mention of the 305 heads seems to come up very very often. The trick of using them to jack up the compression is a trick I started doing in the early 90`s. However, I think too much importance is placed on compression ratios. Lets say we have a 416 305 head that`s stock and on a stock 350.
Beside it we have another dead stock 350 with 126 casting 74cc smogger heads, we`ve bumped the 126 valve sizes up to 1.84 to match the 305 heads valve size. The 126 head has had a nice pocket port done on it.
Now, the 305 headed 350 has 10:1 compression. The 126 casting 350 has 8:1 compression, a whole two points difference. We place them on the dyno. The 126 headed 350 makes more torque and horsepower than the 305 headed 350 did, and why? Flow. Flow is power. When you add flow and compression then your getting somewhere. Next is you mentioned about the valve springs, going to beehive springs are cool and they`ll work, but if you weren`t going that route I don`t think you understand. Anytime you go with a roller cam you must use roller cam springs that match it. Stock vortec roller springs are for a cam that has round lobes, and when the correct valve spring is not used, valve bounce occurs and the power drop through the RPM band can be up to a 30 to 50 horsepower loss. Crane, Comp, Isky, all will tell you on a roller cam you must use springs that match it. However as said, the beehive springs will work and are a great idea to get them on the cheap via junkyard route. Rollers aren`t like a flat tappets where you can use one spring that handles up to .550 lift to cover a big spectrum of cams. I wish they were as that would be the cheap route out but the rollers ramps are far better than any flat tappet design.
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Old 09-07-2011, 07:52 AM
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My reponse is on lifter face diameter controlling how much lift acceleration you can get per degree of cam rototation. The ramps can be reground to whatever , but the lifter diameter was the key. The crysler had wide .906 lifters and had the good factory cams from a point of veiw.

Flow over tiny chambers, nice.
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Old 09-07-2011, 11:15 AM
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1.21 giga-watts???!!!!
 
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Just noticed the duration of the cam that the thirdgen guys recommended. That would put you on a Comp Extreme Energy 262. .469 lift. Check it out. Nice cam. Made 415 HP and 420 TQ on a Goodwrench 350. Do yourself a favor and check out the Goodwrench Chronicles on chevyhiperformance.com
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Old 09-08-2011, 02:10 PM
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Yeah I've read a lot about the XE-262H Comp cam but its a flat tappet, and I don't want to run flat tappet, I'm going to convert my block to roller and take advantage of what it can offer.
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Old 09-08-2011, 03:05 PM
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Then get a roller version of it, Comp does make them you know. You really should invest a couple of minutes and check out the Comp site and educate yourself a bit instead of naysaying anything that is suggested to you.
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