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#1
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Low Buck Cam selection for a stock 1970 GP 400 with #13 Heads
Guys, I am looking to just replace the cam with associated necessary valve train components in my stock rebuilt 1970 GP 400 with #13 heads, and factory Q-jet intake.
The engine came in a 79 TA that a I bought years ago. Haven't really driven it much since I owned it due to various minor leaks in the engine and transmission. I decided that I just need to pull everything out and clean everything, reseal and repaint everything. Figured it would be a good time to replace the cam. The motor runs strong, compression was even when I checked it years ago. I did install headers when I first got it. So, according to my searches on this forum, it looks like the Summit SUM-K2802 cam kit with lifters are a popular choice. The car will get 3.42 gears, and is an auto. Keep in mind that this is a budget build, the motor will be installed in a 1980 Formula that currently has a tired 301. That being said, would this be the right path for a cam choice? Do I need to get new valve springs, what about 1.6 rockers? I do have Edelbrock RPM manifold to install if that would make difference. I also multiple carbs to choose from that a laying around in my shop. Anything else other than the obvious (timing chain, oil pump, ect.)? Just want a nice sounding, decent performing street engine that will not overheat for the future buyer. Thanks Mike
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73 TA #'s Match 73 Formula, Roller 78 TA W72, WS6, #'s Match 79 TA WS6, 1970 400 Ram Air III motor 80 Formula 301, #'s Match 94 TA 2000 TA WS6, Procharged 68 RS Camaro, Roller 80 Z-28, Roller |
#2
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I asked years ago a similar question. The Summit 2802 and. Crower 60243 are very close. They were recommended here, for a 400. I would want to use the Hylift Johnson lifters (with ANY cam). The Summit cam is usually a bargain buy.
You will need specific springs for that cam. You will need to find out what your spring installed height is going to be, before buying springs. Experts here will help you with that. Even though it’s a budget build, zero decking the block is important. Polishing all sharp edges in the combustion chamber and on piston tops is important, and do-able.
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1977 Black Trans Am 180 HP Auto, essentially base model T/A. I'm the original owner, purchased May 7, 1977. Shut it off Shut it off Buddy, I just shut your Prius down... |
#3
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2801 would be a great choice. I have and do use them in a lot of engines such as yours and they work well for a moderate 400 build. I would check the valve springs though, not necessarily because of valve spring binding, but to make sure they're not worn out and you have good enough pressure. I also would install 7/16" rocker studs and poly locks to adjust the rockers. Your stock 3/8" studs may be OK but it's cheap insurance to go with the 7/16" studs. No need to disassemble a good running engine to zero deck it, etc. If it wasn't pinging before this cam isn't going to cause it to start.
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62' Lemans, Nostalgia Super Stock, 541 CI, IA2 block, billet 4.5" crank, Ross, Wide port Edelbrocks, Gustram intake, 2 4150 style BLP carbs, 2.10 Turbo 400, 9" w/4:30 gears, 8.76 @153, 3100lbs |
#4
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This probably depends some on how many miles are on this engine, but it would be a good idea to replace the 2 piece valves with a 1 piece ferrea. I use to have a 13 head from a 70 goat that an intake valve broke and destroyed the engine.
IRC the 13s ran fairly consistently in the upper 70s for volume. Most were 76-78 cc. With the OEM pistons and a .043 head gasket and the bore chamfers that is probably 9.3-9.6 SCR. If your not going to replace the valves I wouldn’t go bigger than a 2801 and stock type springs. We have used a bunch of those cams in various engines. FWIW, We usually run the 2801 below 9.5 SCR on most engines. The 2802 would like more than a stock converter, it needs better valve springs. Well past coil bind...better valve springs=time to replace the 2 piece valves. Both those cams would like a bigger rocker arm. Last edited by Jay S; 04-05-2020 at 06:57 PM. Reason: Edit |
#5
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Thanks for the replies. Looks like the valves are cheap insurance, found the valve sets on Ebay for $189. I think I will go the route of the 2802 cam, just need to know about the lifters, a set comes with the kit, do I need to upgrade? I will also go with the 7/16 studs. I assume that I will need new valve springs, what brand?
I have a 700R to swap if that will make much of a difference for the stall aspect. Thanks Mike
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73 TA #'s Match 73 Formula, Roller 78 TA W72, WS6, #'s Match 79 TA WS6, 1970 400 Ram Air III motor 80 Formula 301, #'s Match 94 TA 2000 TA WS6, Procharged 68 RS Camaro, Roller 80 Z-28, Roller |
#6
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The valve springs depend upon your installed height...
Crower 68404 and 68405 recommended here, a lot. the 68405 is for taller valves. I don't remember the exact specs though.. Buy the Hylift Johnson lifter, period. They have gone up in price, recently, I hear. Still no other better lifter, just pay the price. Paul K. member here sells them...
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1977 Black Trans Am 180 HP Auto, essentially base model T/A. I'm the original owner, purchased May 7, 1977. Shut it off Shut it off Buddy, I just shut your Prius down... |
#7
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The low first gear in the 700r4 will help a lot with a stock stall with the 2802.
With stock length new valves the crower 68404 springs would be a good choice with the 2802. It would also be a good idea to take the oil splash guards off the springs and convert the guide seals to positive type. FWIW, The melling 1.65 rockers are another cheap upgrade. They usually run closer to 1.6 than 1.65 ratio . |
#8
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"... Low Buck Cam selection...Keep in mind that this is a budget build..."
The LOW buck, LOW budget idea ALWAYS gets lost in threads here. Guys will either recommend larger cams, that require stronger springs, 1-piece SS valves, etc, and/or the HL Johnson lifters, that cost more than twice as much as the cheaper lifters. Most also recommend the Crower springs, which are much higher than many others. In fact, from what I've seen, MOST Crower products are higher than most any other similar products, of other brand names. SO, the OP is left to decide EXACTLY how much extra he is willing to spend, in order to buy the best, highest priced parts. Many will say that it's best to spend a few hundred extra now, than to risk an entire engine, down the road. I suppose it's a LOT like buying insurance. May not really NEED it. But, there is no way to know that, in advance. I raced Pontiacs for quite a few years, making lots of passes. Ran 041 clone cams in several 455's, & slightly larger cams, in a couple. Never broke a factory 2-piece valve. But, others have lost engines because of broken factory valves, in fairly mild street engines. So, how lucky are you ? Also, I think I recently read about a Summit cam that was not ground correctly, so that some of the lifters would not rotate. So, maybe some here can speak to that. I suppose the next cheapest cams might be the Melling brand, depending on where you buy. The SPC-7 & SPC-3 Melling cams have been used in lots of 400 engines. There are lots of Pontiac cams in the $150 range. Then there are the Crowers for around $200. Because I was on a super low budget, I bought a Summit 2802 cam, but the Jegs lifters, which are USA made by Delphi. They're the kind with the hardened foot. Delphi has supplied GM & others with lifters, for many years. Other than the hardened foot, I didn't see anything special about the Jegs lifters. They have the typical paperclip wire retainers, which I replaced with real snap ring retainers, from Fastenal. If you don't mind the price of the Hylift Johnson "R" lifters, they would be especially good, if you decide on a Summit 2802 or larger cam, in a 400. Many don't seem to ever mention this. But, according to the HL Johnson catalog description, those lifters are the "bleed-down", or "variable duration" type. Therefore they'll reduce duration at idle & low rpm, then return to full lift, at higher rpm, which many say is somewhere between 3000 & 3500 rpm. But, they do not bleed down as much as Rhoads lifters. Anyhow, for the question asked, there are lots of possible combinations. Which combos will be best, in the long run ? I don't know ? Bigger cams should make more upper rpm horsepower. But, they'll require stronger springs & will put more stress on the rest of the valve train. Smaller cams will idle smoother, make more vac, usually have more low rpm torque, while putting less strain on the valve train. There can easily be a price difference of several hundred dollars, between possible HFT cam/lifter/spring/valve/rocker combos. Last edited by ponyakr; 04-05-2020 at 10:52 PM. |
The Following 2 Users Say Thank You to ponyakr For This Useful Post: | ||
#9
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I've used the Melling 068, or SPC-7. This is the factory tri-power and HO cam. You can get them through most any local parts store, Autozone, O'reilly's, Car Quest, ect. Shop for the best price for the kit with the lifters. I've used it in everything from a 326 to a 421, all with factory springs, valves, etc.
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LEAD, FOLLOW, OR GET THE HE!! OUT OF THE WAY!!! HONEST JERRY'S SPEED AND EQUIPMENT
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#10
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Quote:
AZ currently shows the SPC-7 cam for $120 plus tax. https://www.autozone.com/internal-en...07135_705947_0 All the pics I can find right now, show the Melling JB-951 lifters to be the Delphi lifters, with the hardened foot. These on Ebay, look exactly like the Jegs lifters I bought. https://www.ebay.com/itm/Melling-JB-...8AAOSwk25alwJ7 Summit & Rock Auto show 'em for less than $3 each, plus shipping. For $99 plus orders, you get free shipping from Summit. But they now charge me tax. Some Ebay sellers don't yet charge tax. https://www.summitracing.com/parts/mel-jb-951 https://www.rockauto.com/en/parts/me...ve+lifter,5548 Appears that it is quite a bit cheaper to buy the Melling cam & lifters separate, rather than as a cam/lifter kit, again, depending on where you buy each. As always, Summit may match the best price you can find, on the cam. So, that would match the AZ cam price, plus get you free shipping on the lifters. PS: If anybody has bought some of the JB-951 Melling lifters, IN RECENT WEEKS, or buys some SOON, please post pics of 'em here, so we'll know what lifters Melling is CURRENTLY selling, for Pontiacs. Thanks ! Last edited by ponyakr; 04-05-2020 at 11:47 PM. |
#11
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#12
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Aprox what year did you buy the last set ? |
#13
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What was the $189 replacement E bay valves? Are they a sealed power oem replacement valve?
A stainless Ferrea or Milidon set is about the same price and a better valve than the OEM offerings. Intakes run about $90. If this is a ‘true econo’ build like what Pontyaker talks about you could replace the intakes and keep the OEM exhaust valves. It is generally the intake valve head that breaks. The exhaust valve runs a lot hotter, and will generally bend before it breaks. The exhuast valve probably has a little better metallurgy on the 2 piece weld as well. Exhaust valve usually has the most wear though,so unless you DIY, it is as cheap to replace them as regrind them when your working on the heads. But you could likely just lap in new intake valves and just run it with the old wore out exh valves as they are and it would run a long time. https://butlerperformance.com/i-2445...tegory:1400522 I don’t think the odds of getting bad lifters from the Summit or Jegs brand lifters are any worse than something from Melling. Sounds like most of those are Delphi now, which is probably ok. I would rather run the Hylift Johnson’s and find another corner to cut else where. Last edited by Jay S; 04-06-2020 at 10:21 AM. Reason: Edit |
The Following User Says Thank You to Jay S For This Useful Post: | ||
#14
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Here is the link to the valves on Ebay:
https://www.ebay.com/p/1042061059?ii...BoC5WYQAvD_BwE I initially was going to go with this Lunati 20510712 Voodoo 231/239 cam, or another Voodoo cam. However when I saw that the price was 3 times the cost of the Summit cam I decided to go that route. I realize that there is a lot of different combinations of cams, springs, and lifters of varying quality and price to choose from. I don't plan tearing down the engine past the heads, leaving the shortblock alone. I just don't want spend $1500 on the valve train when I hopefully can get away with spending $300 to $700-800 (not including a stall) depending on what is being replaced. So if go with the 2802 cam swap, the following should be replaced as a minimum: Cam Lifters (Brand/Type?) Springs? (Brand/Type?) Valves?(Ferrea) 7/16 Studs? 3K Stall Converter If I do all of the above, I would like to get a consensus on the lifters and the springs, keeping in mind this not a "race" motor. It will probably get one pass at the track just to know the numbers. Thanks for everyone's input in advance Mike
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73 TA #'s Match 73 Formula, Roller 78 TA W72, WS6, #'s Match 79 TA WS6, 1970 400 Ram Air III motor 80 Formula 301, #'s Match 94 TA 2000 TA WS6, Procharged 68 RS Camaro, Roller 80 Z-28, Roller |
#15
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Looked like you did good selecting the ebay valves. The ones I posted were the longer ra 4 valves. With the bigger cams we use those with a taller spring and the longer Melling 11/32 ra 4 pushrods with a 995 compcams spring. If your pulling the heads off and putting new valve in and want a cheap upgrade on the push rods from the stock 5/16” push rods that works great. That combo with the melling ra4 1.65s is a cheap upgrade.
With stock valve length I don’t know of a better spring than the Crower 68404’s. Quality wise the summit cam is of good quality, just an older profile. That 231/239 Lunati you looked at is an old Ultradyne grind that goes back to the early 1980s. It was Ultradynes claim to fame. Great cam. Save your money on the cam and get some nice lifters=hy lift Johnson |
#16
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Jay. If you use the RA4 pushrods, what do you do for guide plates? Just open up the 5/15 guide plates???
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1977 Black Trans Am 180 HP Auto, essentially base model T/A. I'm the original owner, purchased May 7, 1977. Shut it off Shut it off Buddy, I just shut your Prius down... |
#17
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We have been able to bend the 5/16s guides out just enough to fit the 11/32” push rods. The 3/8” aftermarket guides are a little to wide. The melling RA IV push rods are about half price compared to the hi tech compcams push rods and seem to line the rocker geometry back up with the longer valves.
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The Following 2 Users Say Thank You to Jay S For This Useful Post: | ||
#18
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Low buck with nice power and excellent sound is a factory 066, 067, 068, or 744 cam with 1.65 rockers.
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'70 GP Model J 462 Butler ported 87cc Edelbrock D-ports RPM intake with Holley Sniper 2 CompCams 236/242 hydraulic roller Tribal Tubes tri-y headers TH400 13" Continental "Jim Hand Special" 3.50 9" CurrieTrac, 245/45-18 Front, 275/40-18 Rear |
#19
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I have found if you get a old 11/32 valve,tap it into the guide plate and wiggle it.When I have tried to bend them with like vicegrips I sometimes broke a tab.FWIW,Tom
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#20
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Well, now I am getting a little confused, it looks like changing the cam is starting to get fairly involved parts combination wise. Was hoping to select a cam with new lifters and possibly springs, and rockers. Is there any proven affordable combinations that I can use that will only involve just changing the cam and lifters?
I was also considering the a Voodoo 3 cam. If I choose that, what exactly do I need to get to make it work? Do I buy the Voodoo with the lifters that come in the kit? O,r just get the cam and different lifters? Should I replace the springs at the same time? add 1.65 rockers?. Just trying to keep it simple. Will be running 3.42 gears, and a 3200 stall. Mike
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73 TA #'s Match 73 Formula, Roller 78 TA W72, WS6, #'s Match 79 TA WS6, 1970 400 Ram Air III motor 80 Formula 301, #'s Match 94 TA 2000 TA WS6, Procharged 68 RS Camaro, Roller 80 Z-28, Roller |
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