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Old 05-25-2005, 05:43 PM   #1 (permalink)
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383 Gen I Stroker + Vortec heads = Questions!

I'm putting together a 383 for my DD/tow rig. (2WD 79 350 2-bolt main)

The key word here is BUDGET. If I can get it buttoned up for around $2000 I'll be ecstatic. Realistically it'll be higher after oil, paint, distributor and carb rebuilding/tuning, plug wires, etc, of course. This is a motor I want to idle at 750 RPM with Hoover-like vacuum and lots of low end torque. I don't want high RPM forged race stuff - can't afford it, and won't need it.

I've been doing a lot of reading in the bowtie forum. If you're interested in building a 383, search the Chevy forum for "stroker" and you'll hit some good info.

Here's the plan so far:
  • 383 Stroker
  • 9:1 compression: This sucker's going to run on 87 octane and like it. Period.
  • 64cc Cylinder Heads, Should give me the desired compression ratio.
  • RPM Air Gap manifold (Vortec or reg. pattern, depending on heads.)
  • Powerhouse street friendly setup rotating assembly. Part # 383-1-SK. It's on page 10 here
  • Rebuild a Q-Jet. They work, and I have several already.
  • The rest of the drivetrain is a beefed 12 bolt and TH-tree-fiddy, neither stock.

Question 1:
The Vortech heads. $260 per head @ Summit right now, Part #NAL-12558060. I don't know what to do here. I found a link on PBB to a good article from a magazine, but it's really just confused me further. If I use these heads I need to supply rocker arms (Probably cheapies @ the bottom of page 10, again in the Powerhouse catalog, maybe the more $ ones at the bottom of page 11...)

The problem with these heads is the part where they max-out at .470 lift. Will an appropriate RV cam and 1.5 ratio rockers put me over this? If not, that's great. If so, and I believe that's the case... I'm looking at paying to modify the spring seat, installing new springs, retainers, and rockers. Not such a great deal. I'm assuming your average Rv-style cam, BTW. Basically, how much am I going to have to shell out to run the Vortec heads? This is going to add up.

I know there are some of you in here running Vortec heads on Gen-I blocks. Help me out!

Doesn't anyone sell Vortec heads modified & ready to bolt onto a 2-piece rear-main block fora reasonable price? Or is there a vavletrain out there that will stay within the .470 max-lift spec?

Should I go with Cast-iron L98 heads instead? My understanding from 2 or 3 threads on here is that they're also a 64cc chamber that flows nearly as well as the Vortecs. Are they available assembled?

Question #2:
From reading the threads on 383 buildups, I know a couple of you in here are running Powehouse balanced rotating assemblies... Are you satisfied now that you've got a couple miles under your belts? Since this motor won't be hammered on or wound above 5500 RPM, I'm not worried about runninf an Eagle forged crank and uber-bling connecting rods. Budget is the word.

The only truly relevent info I found on Vortec heads is from this thread, along with snippets from guys allegedly running Vortec heads that posted in the various threads on building 383s that I sifted through:
Vortec Head Swap thread on PBB

At least you can tell I searched.
Evan

Oh, here's a decent current thread on building a 383:
/forum/chevy/358564-383-rebuild.html
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Old 05-25-2005, 09:20 PM   #2 (permalink)
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I live in the same town as powerhouse and shop there all the time. Im a fairly hard core drag racer and as a racer and if I was building a race motor, I would not buy a powerhouse kit for my racecar unless I was building a budget grenade. HOWEVER, I havn't heard any bad things from mild street aplications coming out of their shop so in essence, I wouldn't have a problem recomending their stuff for your app.

as for heads: the vortecs are fabulous heads if you can get ahold of one. .470 lift isnt too bad for a mild street towing motor. lets see if I can dig around and reccomend a few cams that will fit your needs.

are you wanting to run hydraulic flat tappet or do you want to make the commitment and go hydraulic roller? I'd go roller if I had the cash laying around.
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Old 05-25-2005, 09:27 PM   #3 (permalink)
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the comp cams 12-235-2 xtreme 4x4 cam (.447/.462 210/218 on a 111*)would work with those vortec heads and work pretty well. should still net you some decent mpg also. if you want to spend the extra dough on the bigger springs a bigger bumpstick is in order but not too big.

My cam for my TPI 383 is as follows .488/.509 .214/222 on a 114 but its hydraulic roller. I wouldnt go much bigger than this at all for a DD/towing motor.
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Old 05-25-2005, 10:12 PM   #4 (permalink)
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Quote:
Originally Posted by Buckshot33
the comp cams 12-235-2 xtreme 4x4 cam (.447/.462 210/218 on a 111*)would work with those vortec heads.
Run this cam with Vortec's and you'll be cool. The Vortec's are 67 cc's and will lower your 9:1 just slightly, but will be what your looking for.
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Old 05-26-2005, 02:21 PM   #5 (permalink)
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Quote:
Originally Posted by Buckshot33
The vortecs are fabulous heads if you can get ahold of one.
GMPP is selling new assembled ones. They're $260 through Summit right now. There's a link in my first post.

Quote:
Originally Posted by Buckshot33
Are you wanting to run hydraulic flat tappet or do you want to make the commitment and go hydraulic roller? I'd go roller if I had the cash laying around.
I WANT to be running a Roller. I WILL be running a flat tappet. Like you mentioned, Cash.

This is going into a '79 C10 I got for free in return for some 'cage work for a friend. It'll get $4-5K dumped into it to fix 200,000 miles of worn out drivetrain, suspenion, brakes, rust, etc. and then I'll repaint it myself. I've budgeted $2k for the motor, which is EXTREMELY conservative when building a stroker. I expect to go over it. When I'm done my DD VW Convertible will get sold for $3,500 - $4,000 and I'll get most of my money back.

Quote:
Originally Posted by Buckshot33
The comp cams 12-235-2 xtreme 4x4 cam (.447/.462 210/218 on a 111*)would work with those vortec heads.
Code:
Per Summit's website:
Valve Lift with Factory Rocker Arm Ratio: 0.447 int./0.462 exh. lift
Terrific. I drive past Comp a couple times a week, and a fellow wheeler works for them and may be able to hook me up. Comp is good stuff, and the heads & cam are the two places I've decided my engine can't afford for me to cheap out.

Quote:
Originally Posted by MrWillys
Run this cam with Vortec's and you'll be cool. The Vortec's are 67 cc's and will lower your 9:1 just slightly, but will be what your looking for.
This is terrific, Buckshot and MrWillys, you guys ROCK! I was nearly certain last night that I'd have to run the factory heads and suck up the 50HP loss, since I'd be spending $500 per head on sotck world power's or machined Vortecs. But if I just have to buy a decent set of rocker arms (Stay 1.5:1 to keep it under .470 lift, right?) the Vortecs are definitely my best option.

Everyone lists the Vortec's at 64cc. Are you sure they're really 67s?

That might be better, actually. I'm almost sure my block will need to be decked, and that way I can run a standard thickness gasket @ 9:1 if it's not excessive.

Anyone have any other suggestions on parts to consider? I'm fairly set on the QJet carb, but the distributor is a concern. I have an Accel coilto drip into an HEI cap that I imagine I'll run... but I'd like a good setup that'll let me adjust the mechanical advance curve and adjust when the vacuum advance comes in. What's the most common solution to getting the timing spot-on throughout the curve on a motor like this - what should I do since the factory advance curve will probably be off, given I don't want to spend a fortune on an MSD distributor or similar?
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Old 05-26-2005, 02:36 PM   #6 (permalink)
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I was wrong, the combustion chamber volume is 64 cc. This is ok though, beacause you can run a dished piston. Check this out: http://www.customclassictrucks.com/t.../0405cct_head/ You'll have to scroll down quite aways.
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Old 05-26-2005, 02:54 PM   #7 (permalink)
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drop 180 bucks on an msd 6al ignition box for your HEI and you'll never look back. I gained almost 2 mpg and a a good seat of the pants gain when I added mine. you can have a good shop recurve your distributor if you want too but I didnt mine and my 406 runs like a raped ape from idle to 6,000 rpm


yeah stick with 1.5's because with 1.6's you're looking at .476/.492 lift on that cam.

about 10 years ago we build a towing motor for a 1 ton crewcab SRW 4x4 we had. we played the whole crane RV cam, 882 heads type thing. we called Holley and asked them what the best carb they would choose for a towing motor going in a heavy truck for best power and milage. guess what HOLLEY told us to our face... RUN A Q-JET.
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Old 05-26-2005, 05:09 PM   #8 (permalink)
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Quote:
Originally Posted by MrWillys
I was wrong, the combustion chamber volume is 64 cc. This is ok though, beacause you can run a dished piston. Check this out: http://www.customclassictrucks.com/t.../0405cct_head/ You'll have to scroll down quite aways.
Don't worry about it. The kit I'm looking at specs 9:1 compression with 64cc heads, so that's what I've been after all along.

I think we'd all rather run a dish than a dome for flame propogation reasons... and I have to assume that's what the kit comes with.
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Old 05-26-2005, 05:20 PM   #9 (permalink)
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Quote:
Originally Posted by Buckshot33
drop 180 bucks on an msd 6al ignition box for your HEI and you'll never look back.

Yeah stick with 1.5's because with 1.6's you're looking at .476/.492 lift on that cam.

Guess what HOLLEY told us to our face... RUN A Q-JET.
Thanks buckshot. That's exactly what I'm after.
I'll post up when I'm starting to build and have addition questions. Now I just have to decide on a sexy pair of valvecovers. I'm gonna keep an eye on EBay and try to score a set with the corvette logo cheap. That'd be great for impressing friends - most of whom know schit about engines.
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Old 05-26-2005, 05:25 PM   #10 (permalink)
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these are my old stand bys for valve covers:

I do them a little different than most though.




first is the TPI 383 in the scout
second is the 433 in my nova
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Old 05-27-2005, 10:11 AM   #11 (permalink)
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Sexy. After a little searching, I think I'll keep an eye on EBay, score a set of factor centerbolt covers cheap, and paint 'em to match the truck. Chrome isn't me. This engine will be a blue block and graphite-gray colored accesories in a gloss black engine bay. Normally I'd paint the engine orange, but this is going into a navy blue truck with a gray interior. That'd look horrible.

I found a link to an article in Car Craft that's very similar to what I'm doing. Even used a Powerhouse kit. The main differences are that my motor will shave some $$$ (and HP) off by running lower compression, and a cam that doesn't require doing anything to the Vortec heads except bolting on some 1.5 rockers.

I'll also be using my existing block.

Parts estimate:
$500.00 (Pair) Vortec Assembled Heads, GMPP #12558060
$690.00 Powerhouse Ext. Balanced rotating assembly #383-1-SK
$250.00 Comp Cams / Lifters(?) / Rockers(?) #12-235-2 xtreme 4x4 cam
$070.00 Pushrods
$008.50 Freeze Plug kit
$190.00 Edelbrock RPM Air Gap for Vortec Heads #7516
$025.00 Accel PLug Wires #5048B
$010.00 Melling Oil Pump #M55
$040.00 Valve Covers, Stock Centerbolt
$150.00 Headers(?)
$250.00 Machining Block & Installing cam bearings
----------------------------------------------------------
$2,183.50 Total

Those prices include some WAGs (wild ass guesses) and some hefty discounts. I can get a discount on Comp Cams stuff through a friend (If I can find his #)... and one of the local parts chains I can chop 20% off the price of anything they can order - usually after matching a competitors (or Summit's) prices, but not always. That includes all the stock stuff (oil pumps, pushrods, etc) along with some of the performance stuff like plug wires and the Air Gap manifold. One of their employees has a hook-up on machining the block as well, I think.

I'm gonna try to find some of that stuff on Ebay or from any place that sells it the cheapest to slice the price down some more.

This should be fun. If I can find any way to get the motor under $2K total, I will... but it'll be tough: That didn't include a lot of stuff like an air cleaner, oil, paint, etc. But I'm gonna try like hell.

Time to go find some good TH350 buildup threads,
Evan
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Old 05-27-2005, 09:53 PM   #12 (permalink)
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I built a pretty stout 383 for about $2200. The only thing I used that I had was the block. Machine work was around $500. I got an eagle crank, scat rods, and an overhaul kit from summit that was $310. Came with pistons, rings, gaskets, freeze plugs, bearings, and an oil pump. I bought a new oil pan, timing chain cover, edelbrock intake and carb, comp cam, new heads, and an engine bolt kit. You should be able to get everything you need for right around $2000.
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Old 05-28-2005, 07:52 AM   #13 (permalink)
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Isn't the RPM series of intake ment for a square bore carb (i.e. holley). I think you need the regular performer or airgap performer.
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Old 05-28-2005, 08:35 AM   #14 (permalink)
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Gasket Kit, Fluids and Filters, The M55 pump is $25, I'd budget $350 Shipped for a nice set of headers you wont be replacing very soon. If you get headers, how about the rest of the exhaust meeting up with the headers? Header wrap is useful stuff... oil pump driveshaft?, either that or replace the plastic collar on the old one, but I'd just get a new one... New head bolts are cheap insurance, (pioneer brand is inexpensive). Main Studs are a good idea, but then youre forced to align hone youre mains (probably not necessary). I didn't see where youre located, but a block heater is only $25 or so to replace one of your freeze plugs. Theres probably more stuff mising, but thats all I could think of off the top of my head...
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Old 05-30-2005, 08:19 AM   #15 (permalink)
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Triaged - Whoops. I'll run whichever Edelbrock or Holley dual-plane manifold I can get a good price on that fits a spread-bore like the QJet I'll be running.

Mountian - All of that had occured to me before, but thanks for the re-hash. I keep being tempted to just run factory exhaust manifolds, but then why do all the work on the intake and the heads just to try and push everything out of a tiny cast iron POS?

If you'll excuse me, I'm going to go start searching the forum for ideas on interior cage / custom sheetmetal dash stetups
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Old 06-02-2005, 09:38 AM   #16 (permalink)
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Quote:
Originally Posted by Triaged
Isn't the RPM series of intake ment for a square bore carb (i.e. holley). I think you need the regular performer or airgap performer.

So's the Performer intake. Although I think the Performer is a better choice for a mild-cam towrig engine. I've got the RPM intake/cam combo & it's definitely not an off-idle setup.

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Old 06-02-2005, 09:54 AM   #17 (permalink)
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i run the vortec heads, my cam is 520-540 lift hydraulic roller,comp cams roller rockers,guide plates,springs are up to 600 lift, rpm air gap, demon 750, it runs very well, you can save alot by using factory style rockers,and smaller cam, factory style center bolt valve covers, excellant power found in these heads
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Old 06-02-2005, 10:00 AM   #18 (permalink)
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I got a set of vortecs of a guy on ebay who rebuilds em, stainless valves, can get 2.02/1.60 if you want, bronze guides, springs to handle .510 lift or something like that and some other little stuff for $600 to my door. I ported the exhuast ports and got some real nice flow improvements...theres a article in car craft or one of those mags about porting them and I basically followed that. I stuck em on a 355 and it seems to be running pretty nice so far...
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Old 06-02-2005, 11:04 AM   #19 (permalink)
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Remember when calculating your compression ratio that using a stroker crank (3.75") is going to give you more compression than a stock 350 (3.48") crank would.

I think vortecs are going to push your compression ratio higher than you think because of the 64cc chambers. I've heard people say that they've measured their votecs and got a 62cc actual. And if you're going to deck your block, it will get higher (compression)
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Old 06-02-2005, 02:35 PM   #20 (permalink)
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You're probably right, Tex, the spread-bore Vortec manifold is a Performer (Part #2116)... which is defintely a better choice for me. I was thinking air gap since every motor they're dyno'd on in the mags shows more power everywhereversus smaller manifolds, but something obvious occured to me. None of the car mag test list results below 2500-3000 RPM. That's their definition of "low end"... mines a wee bit different, and the 2116 is a better choice for this motor almost for certain.


Chevy... I believe you're right about underestimating the compression. Let me ask those of you who've got some experience with bowtie motors: Is it easily possible to end up at 9:1 compression with 62-64cc heads - assuming a 3.75 stroke crank and a bock that's been decked a couple of thousandths? I actually don't know what will be required as far as machining since the motor is still in the truck - I'm simply planning for the worst-case scenario.

I mean, is the dished piston this will require a fairly common part, or am I going to have a 1/4" deep canyon on these suckers?
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Old 06-02-2005, 04:24 PM   #21 (permalink)
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If you go to the speed pro website they have a calculator you can use. They also can give you a rough idea with a 64cc head. You could really go to about 9.3, or maybe 9.5 on pump 87.
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Old 06-02-2005, 05:37 PM   #22 (permalink)
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You could really go to about 9.3, or maybe 9.5 on pump 87.
I think youd have to retard the timing too much to run 87. The cam mentioned earlier in the thread will develop a lot of cylinder pressure, I think 9.5 is as high as youd want to go using iron heads, even with premium. Vortec heads dont need as much timing as some earlier heads, but you may end up running premium with a 9.5:1 cr. I believe you will end up running dished pistons to achieve the cr youre looking for, which is fine, they are readily available, and I've heard theyre actually more effecient than flat-top pistons...
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Old 06-02-2005, 05:53 PM   #23 (permalink)
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I think youd have to retard the timing too much to run 87. The cam mentioned earlier in the thread will develop a lot of cylinder pressure, I think 9.5 is as high as youd want to go using iron heads, even with premium. Vortec heads dont need as much timing as some earlier heads, but you may end up running premium with a 9.5:1 cr. I believe you will end up running dished pistons to achieve the cr youre looking for, which is fine, they are readily available, and I've heard theyre actually more effecient than flat-top pistons...
The cam in question is really quite mild. RPM range is 1000 to 5000. Most motors with 3.75 stroke or less can run up to 9.5 with 87. But what do I know. Timing will depend more on whether it's injected or not.
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Old 06-02-2005, 07:56 PM   #24 (permalink)
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The cam in question is really quite mild.
Beautiful motor in that Willys... Thats gotta be a lotta motor for a light truck!

I agree. However, mild truck cams contribute to cylinder pressure by having little overlap and duration. Because the intake and exhaust valves are not both open together for very long, higher cylinder pressures are developed even if static compression numbers are numerically low. This is also what contributes to low rpm torque, and a powerband starting at 1000 rpms. It is also because of this I am wary of using higher crs when a cam like this is used. The 4x4 extreme cam has an overlap of something like 35 degrees, which is extremely little overlap. You can actually use a much higher cr if you have a wild cam with lots of overlap and duration. I'd go up to 10.5:1 with iron heads, 11:1 w/ aluminum, if it was going in a sports car with a corresponding cam choice.

Since he mentioned using a carburetor, timing will be fixed, (no knock sensor) so I think its better to use something like a 9:1 cr with 87 octane, and curve the distributor for more timing advance. I'd personally use 9.5:1 and run high octane if it turns out to be necessary. As I mentioned, the Vortec heads require less timing, so I could be totally wrong.

I also tend to err on the conservative side, if I build a motor for a customer with directions to make it run on 87 octane, and it doesnt, I've got a problem.
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Old 06-02-2005, 08:14 PM   #25 (permalink)
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The cam in question is really quite mild. RPM range is 1000 to 5000. Most motors with 3.75 stroke or less can run up to 9.5 with 87. But what do I know. Timing will depend more on whether it's injected or not.
Mild cams need lower compression then a high duration/lift cam. This is because a high duration cam will bleed off some of the cylinder pressure at low rpm (in favor of better cylinder filling at higher rpm).

If you want to do more searching you could look up Dynamic Compression Ratio (DCR). It is DCR that determines what grade of fuel you need to use.

Engine analyzer will calculate the DCR for you (along with a bunch of other stuff) and there are other calculators out there that are more basic.
http://home.earthlink.net/~triaged/ea30.zip
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