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ReBuilding a 326
Hello All, I'm new here and have been following the threads about Cam selection. I have a question about cam/spring tension to use. I just bought a 66 LeMans with a stock 326 block and heads(094). Been buying parts for a restoration and engine rebuild. Based on recomendations from another Pontiac forum I bought a Comp Cam from Summit #CCA-51-224-4 Camshaft, Hydraulic Flat Tappet, Advertised Duration 274/286, Lift .488/.491 . What I'm wondering is if anyone has a recommendation for springs and lbs of tension they should be for this cam. I'm still in the learning stages of this engine since I haven't had a Pontiac before. Thanks in advance, Daryl
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Looking at the summit page for that cam, they recommend the comp 995 spring.
What rear gear and transmission are you using? The duration @.050 for that cam is 230/236, which is fairly radical for a 326 |
That #995 spring will probably be way too much spring for the 326 heads. You need to check the spring installed height and find some springs that will achieve 115-130 lbs. on the seat[because the intake seats are 30°, they need more seat pressure] and 300-320 lbs. open, and it will be happy. IIRC, the 326 heads will set up around 1.550-1.600 or there about. The #995 spring will give about 150-170 lbs at that height.
It's easy to find a spring from the spring catalog. Just follow these steps: Write down the installed height. Let's say for this example it's 1.565". Now write down what the valve lift will be. Let's say it's .489" in this case. Now, you can look up the springs in the dual spring section by O.D. to find a spring that is the right size. Now, write down the valve spring rate, in this case we will use the Comp # 995 spring, which is 402 lbs. per inch. Then we need to know what the spring is rated at. In this case, the # 995 spring is rated at 115 lbs. at 1.700 height. Write down the coil bind height. In this case it is 1.020". Now you have all the info, so you just need to do the math. The spring is rated at 1.700, but your installed height is 1.565". You need the difference between them, which is .135". Now you multiply the spring rate by the difference of .135" which is 54.3 lbs. Add the 54.3 lbs. to the 115 lbs. the spring is rated at when installed at 1.700". This gives you 169.3 lbs. on the seat. Now you have a valve lift of .489", so if you multiply that by the spring rate of 402, you get 196.6 lbs. Add the seat pressure of 169.3 lbs to the 196.6 lbs., you get 366 lbs. open pressure. Now if you subtract the amount of valve lift, or .489", from the installed height of 1.565", you get 1.076". Subtract the coil bind height of 1.020" from the open height of 1.076", and you have .056" of spring travel before the spring becomes solid, or coil binds. Here you want a minimum of .050" coil bind clearance. In this case, the #995 spring would be way to stiff for a hydraulic flat tappet cam, but just right for a hydraulic roller cam[if one could be found with only .489" lift ;^]. |
Agree that that is a lot of cam for a 326. If it's mostly a stock build, you will not be happy with that. If you want something that will drive and behave nice, but have good power, I would suggest something like the Lunati VooDoo # 10510700, which is 207/213 duration at .050". This cam will idle nice and pull real strong in a stock type326 build. If you want a little more attitude, you might look at the 10510701 which is 213/219, but unless you make other mods like good exhaust and 4 barrel carb, maybe even a bit of stall converter, and gears I wouldn't go this route.
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I agree, that cam is way to big for the stock 326, plus with that kind of spring pressure you'll pull the studs right out of the heads after a short time of running. That cam would be more suited for say A 400 or 455 with a little bit of compression , something close to 10-to 1 comp. Those heads won't breath enought for you to get anything out of that cam. Go with something a little smaller or you won't like the way it runs or TRYS to idle.
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326 beast!
First off, welcome to the forum. You are now connected to the most elaborate, comprehensive and helpful use of the internet ever! The people here are top notch and you are in good company!
I am glad that you are rebuilding a 326. They usually get the "Cheaper to build a 400" mantra and people usually scrap them. :mad: That said, the 326 is an awesome mill. But over camming is an issue. While they rev great, the combination of parts usually do not allow the use of higher HP parts. The 094 heads are the lower compression heads of 66. They will live on pump gas better than the 095 heads that will bump up compression to over 10:1. Here is a good link to see the config of the 094 heads. They have relatively small valves compared to the rest of the Pontiac engines, because the bore is small on a 326 and if they were bigger, you would have issue with the valves hitting the block. https://sites.google.com/site/ksmsin...ontiac-head-id The first cam that GTOFREEK recommended will ROCK in a 326!! If this is your first Pontiac, the 326 is NOT a 327 Chevy. 207/213 SOUNDS small, but in a Yak will explode with torque off of the line! But will run out of breath at 4500 or so. Which is fine as 99% of cars live in the 2-3K RPM range. I currently have a stock rebuilt 1966 326 with 094 heads that had a 2BBL. It was a replacement engine from Sears I think in the 80's by a previous owner of my 1967 Tempest Wagon. All I did was swap to a 4bbl intake and slap on a Holley 570 CFM carb. I did make it has a 4 speed, and it came with 2.56 rear gears. Car runs great! I Just took it on a 350 mile cruise Friday and Saturday. Kept up with traffic at 70-75 mph and got close to 18-20MPG even with my foot into it. P.S. Buy the correct heads gaskets. DO NOT BUY FEL-PRO 8518!!!!!!! They will not fit! They look like they do, but you will have too much quench around the bore and will blow the head gasket.. |
Thanks for the quick responses and suggestions on the cam. In my initial post I should have mentioned the other mods that I have planned for the 326 and the rest of the car. Only bought it a week ago so I haven't gotten to everything yet.
I would like to keep this car for the street only, but with some aggressive features that won't break my bank account. My plan is to do a full restoration, ie lift the body off the frame but not a full rotisserie. Clean up the frame and patch a couple of small rust holes in the floor pans and a couple in the trunk pan. Do the usual POR15 on all the vulnerable rust prone areas. Restore and paint the body which in fair condition except the rear drivers side wheel well needs a new panel welded in. Re-wire the car with all new harnesses. I tore out the interior yesterday and will be replacing it with a completely new interior and keep the gear shifter on the column(maybe). Restore and upgrade the drive train. It currently has the stock two speed transmission and I would like to upgrade it with a four speed automatic or possibly something maybe easier make fit with a TH350 3 speed. I understand there is a th350 available somewhere that bolts right into place with minimal modification to the transmission crossbar and mounts. I don't know what's in the rear-end yet. If I keep the 094 heads I'll port and polish them to open up any restrictions and improve air flow. Replacing the original exhaust manifold with full length headers and stainless dual 2.5 inch exhaust. Replacing the stock 2 barrel carb and intake manifold with an Edlebrock Performer RPM intake and a Summit 650cfm 4 barrel carb. Convert the front drum brakes to 11 inch disk brakes and swaping out master cylinder with a new master cylinder and an 8" booster. Eventually swap out the original distributor(points) with an HEI unit(electronic). I'll go through the engine and see what the bottom side looks like when the time comes. Thanks |
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Just make sure that it is a BOP TH350.( Buick,Olds,Pontiac) |
1967Tempest, you mention to not use the FEL-PRO 8518!!!!!!! because they don't fit and will blow out. What have you used that works better for head gaskets? Thanks Daryl
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The RPM intake may be a bit much also for a 326. I would find and run a factory 68-72 iron intake. Damn good intake manifold and very hard to beat on an engine like this. I would then get Cliff Ruggles[on the boards here] to build you a Q-jet instead of running that Holley. You would have one awesome running 326 that looks stock, then! |
Agree with Paul on the manifold. Either `68 to `72 cast or the regular Performer. Maybe even look into a light stall converter, depending on the gears/trans used.
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I`d also look into getting the rocker studs pinned or swapped out to a screw in stud to keep em from pulling out with more spring pressures and rpm`s. Those Voodoo cams will wake up that little engine.
Once again, that 274 cam is way too much so, return it if you already bought it. See what starting a new thread does?;):) |
As already stated the comp cam you selected is not the correct cam for your build and it would idle terribly and have no power. That cam would work if you had ported heads, headers, a high stall converter and 3.90:1 rear gears and then you would need forged pistons and rods etc and it would be noisy and not too much fun to drive on the street. I second the Lunati VooDoo # 10510700 cam that would be a great cam for the 326, good idle great off idle power and lots or torque for the small cube long stroke motor. I also agree the RPM manifold is way wrong for your build, the best manifold would be the factory 68-72 Q-Jet manifold and forget about the Holley. And make sure you use made in the USA Hy-Lift Johnson lifters unless you want to have ticking lifters. Good luck with your build.
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I did some math based off of Comp cams catalog spring specs and I figure you will need the #994 spring and have it installed anywhere from 1.625"-1.650". That should give you around 120-130 on the seat and 295-315 open, depending on rocker arm ratio and installed height. You need to see where your installed height is now, and decide what needs to be done to get it to 1.625"-1.650". There are several different things that can be done to change installed height, so it would help to know where you are now, to avoid speculation. I don't remember where the 094 heads setup at, or if I have even done a set. Done 092's, 093's, and such, I'm pretty sure the 094's will setup about the same.
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So now my shopping list is almost complete. :) I'm going to use the more aggressive VooDoo #10510701 camshaft and your recommended #994 springs. I can return the other cam that I had purchased from Summit. It's just shipping costs! I'll have to take off the valve cover to measure the Installed Height but it will have to wait till the snow storm clears here in Maryland. We got hit by snow/sleet and freezing rain today and now it's too cold to deal with that tonight. I wish I had another garage for this project but it's outside till I get my 34 Ford Coupe finished and out of the way. |
And dont forget, as stated before, install a TH350 trans for more off the line than any engine mod will give you. The ST300 is "missing" 1st gear from the vantage point of a Turbo 350 or 400. 2.52/2.48 vs 1.76.:2cents: Keep us updated.
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I thought the Cometics had the correct "bulges".
this is a 350, but it is similair to the 326. Incorrect 8158. http://i689.photobucket.com/albums/v...ps3e5ea07c.jpg the correct 326/350 victor Reinz gasket. Which you cant get :( http://i689.photobucket.com/albums/v...ps8c2d7960.jpg |
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Thanks |
Nope, it's an original gasket. GM Part # 9790081. It also has another part number on it of 3401. The other gasket I was thinking of must be for a 350, because it is too big also.
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I found a Mr.Gasket head gasket from Summit
Mr. Gasket Ultra-Seal Head Gaskets 5810G. Head Gasket; Ultra Seal; Head Gasket; Solid Steel Core; Laminated Outer Facing; 4.205 in. Gasket Bore; 0.038 i The profile and material content sound like it is the correct one but has a larger than expected Bore size. Might be because of the cutouts on the inner sides of the bore. Has anyone used this gasket with success?? |
Based on what "gtofreek" mentioned about the 3401 stamped on the head gasket he has, I found the "Victor Reinz #3401vc" that has good reviews. It was tough to locate but I found it at DavesDiscountParts for a reasonable price.
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I built a 326 a few years ago too- the owner also wanted to use the stock heads too, but when I heard his power expectations we both knew better heads were needed. We opted for KRE D-ports milled to 58cc and fitted with 2.05/1.66 valves. The chamfers did need to be repositioned to work with the KRE heads, but it was well worth the effort.
Cam selected was a Comp cams XE 268H- it has your typical lopey Comp cams idle, but it still works with the power brakes. Stock Sealed Power pistons were used for different reasons, but 4340 H-beams were used along with the stock crank to help the rotating assembly balance without Mallory metal. The block was also decked and SCR was set to 10:1. We also used the Victor-Reinz 3401VC head gaskets. The 326 was finished off with a port-matched performer, Holley 750 Vacuum secondary, and Hooker Comp headers. So how did this build turn out? The owner loves it, and has trouble convincing people it's only a 326 and not a 400. Imagine what this little 326 could do with some head porting and a roller cam. The 326 has alot of potential most Pontiac owners never realize. http://i932.photobucket.com/albums/a...g?t=1386655566 |
326 was a good little engine in its day and a rebuild is fully justified to maintain the value and originality. but for any other reason a 400 makes better sense
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DONT LISTEN!!!! LOL!!! :) Seriously you will not be unhappy with a 326. They run cool and last forever! If you were closer, I would unload the wagon and take you for a hell ride. You would swear its bigger and has more power then a 326. Did you actually get a tracking number for those head gaskets? If so I need the phone number as I am ordering what they have left!! Thanks Dave |
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I actually just received a REFUND notice from my Head Gasket order . Back to square 1. |
I knew it! I will help out and see if I can find some.
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head gaskets
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OUT OF STOCK :mad: |
I've got a set of the 3401VC gaskets. Not sure what they are worth, maybe $40? I know they were hard to find when I needed them a couple years ago and somehow I ended up with a couple sets. Current project is a 400 so won't be using these. Steve
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Daryl Here are the pics.
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Checked and found out they supposedly stopped making them about 3 years ago. Gaskets for the larger bore engines will work, but lose a little compression. (They do there job and seal up the engine.) You should get the ones from helmerrock. I think that is your best bet at this point. PY should check into having these reproduced if enough people submit it to them to make it worthwhile.:2cents:
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Ill bite. Make 326/350 gaskets PY!
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Hello,
I've been following this thread because I too am rebuilding a 326 right now. I was hoping to clear something up regarding the head gasket discussion. The nicely contoured 350 specific gasket is just that, a 350 gasket. The combustion chamber and "notches" in the bores are offset to the outboard side on the 326 and that 350 gasket would be a big no-no on a 326. It would be nice if someone made a more contoured gasket for the 326 as I hate giving up the compression using the #8518 but it will do the job as mentioned previously. Here's some pics of mine showing the off-center chambers and notches. Just trying to help, Ron.:) |
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Last night on my way home from work I stopped by my local machine shop (JB Auto Machine Shop in Baltimore County) to see if they had any left over Victor Reinz head gaskets but no luck. I ended up buying a set from a member on this forum. Thanks Steve. We also discussed having work done on my 094 heads to improve performance. ... milling(about 0.020) to increase CR, hardened valve seats on the exhaust ports, replacing rocker studs to screw in type. I'm going to do the porting work myself. That should be about it for the head modifications along with a new flat tapet VooDoo LUN-10510701 cam, new cam bearings, hydraulic lifters and new springs. |
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The Factory 068 cam is also a nice choice for a 326. ;) Will broaden the rpm power band with that small bore. Elongate the pushrod holes and run 1.60 or 1.65 rockers. |
Here is me cruising in my old 1962 Catalina staion wagon 9 passenger. It had a 1967 326 with a 4 bbl with a TH350 2200 stall and an 068 camshaft.
Car ran great and SUPER cool. The only thing that was eh, was that this engine was a tad under powered. And by tad I mean a tad, with 9 people in it going up a big hill, the temp would get to about 190*-200* and then right as rain it cam down to t-stat once we leveled out. I must mention that that was keeping up speed at 40-50 mph. This video doesnt really do it justice, but you can see no hesitation on it pulling. Dave http://youtu.be/FL_QQdM7Ns0 |
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Thanks! |
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