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Old 10-09-2014, 11:32 AM   #6
MilzyZ34
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Location: Dayton, OH
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Quote:
Originally Posted by Redog View Post
And you have to remember that you cannot just do a cam swap. The engine is balanced for the stock cam that's in it.

Like Shiwnath said, you have to have the heads worked to accept the cam. You will most likey need new valve springs, and you really shouldn't reuse the old lifters. A higher ratio rocker arm may be needed to get the full benifits of the cam. Shorter push rods, too. If you reuse the stock push rods, the valves will open at the same rate and the car will not be any faster. Somebody on here spent over $7,000 on a rebuild, used stock push rods, and was only .1 seconds faster than my car. I would also do a 3 angle valve job as well

You will also need larger injectors, new cam bearings, and like I said, everything is balanced, so you'll need to have the crank turned, and new main bearings. At this point, you might as well get new main caps, a crank scraper because it's a cheap HP Free(er) and P&P manifolds with a larger TB will help get the air in and a set of headers with a nice exhaust would complete the deal.

So my advice is: either save your money for the engine rebuild, or put the $349 into a set of P&P manifolds and a TB which will help you now (if you haven't done so already)


Changing the cam does not alter the balance of the engine enough to cause any adverse effects.

The Stage 1 cam's we offer do not require headwork of any kind, you can even use the stock valvesprings, but we recommend changing the valvesprings out for LS6 valvesprings. If you don't change the valvesprings, you cannot raise the rev limiter of the engine because the stock valvesprings will not support rpm above 6000. Just because the cam does not require headwork does not mean it cannot benefit from it. If you want to get the most out of the setup, heads are a must, but at that point, I would go stage 2 instead of stage 1.

You can re-use the lifters with our cams, we've been doing it for years. All the cars that set the records like the 13 second NA times, used their original lifters. This was of course before we offered the LS lifter spring upgrade kits we have now. If you go Stage 2, I would definitely get them to go with the 560 lift and 128lb valvesprings (stock are 77). It wouldn't be a bad idea on a Stage 1 setup, but not as crucial as stage 2.

I'm not sure why you say you need a higher ratio rocker arm with a cam to get the most out of it, and if you did run even just a 1.7 rocker instead of a 1.6 on one of our big lift cams, you're going to start breaking stuff. You don't need rockers, none of the builds we've done to date on any 60 degree engine had aftermarket rockers.

Pushrods would need to be longer if anything, not shorter. When you have a cam made, they grind the lobes with a reduced base circle diameter instead of just moving the max lift outward from the cam, so that at max lift the cam can still physically be installed in the engine (lobes not sticking out past journals). When you reduce the base circle diameter, depending how much they reduce the diameter, you may need to lengthen the pushrods to compensate. With many of our cams, we can re-use the stock pushrods or use stock length pushrods with a cam because eventhough theoretically they would call for longer pushrods, I've found that the stock lifters are pre-loaded a little too much for my taste, and engines seem to do better if I loosen that up a little, so when we do this, we effectively have .020-.030 less pre-load on the lifters. (.030" is about half of a 1/16"). All this also depends if you are milling heads or not as this has an effect on ideal pushrod length. Now if you too long of a pushrod (like you were saying the stock pushrods would be when you said they should be shorter), the valves would not open at the same rate [as stock] as you suggested. The valves are going to open at a rate based off the lobe of the cam currently installed. If the pushrod is too long, then even when the valve is supposed to be closed, the pushrod will have depressed the lifter past all the pre-load and bottomed-out, and will then start opening the valve. When the valves are open like this all the time, the engine will have no compression and will not run.

The 13.9 second NA grand am, also used stock length pushrods.

For valvejobs, I prefer more angles like our Stage 2 and higher heads.

Stock injectors are 19lb/hr for a 99 and earlier car, and 22.5 for a 2000+. The 19's are already very small, and will max out quickly. They need to be replaced at about 210hp. The 22.5's need to be replaced at before 250hp. At these values, the injectors are at about 90% duty cycle at WOT. Ideally you want them to be around 67-72 at WOT, and the injectors will last much longer. So a Stage 1 cam car with no heads can probably keep the stock injectors, but if you go stage 2, this is why the stage 2 kit comes with 36lb/hr injectors. Then you never have to worry about injectors again (atleast for NA).

You don't need new cam bearings, or an engine balance, or crankwork to install a cam.

OK, all that being said, this is the usuaul sequence of mods I suggest for people with 3400 engines ...

First, get these mods ... PCM, AL 605 plugs (1 heat range colder), 180 tstat, 2.5" downpipe (no cat and EGR delete if there is no need for emission testing)

throttle body is next, but need to decide how far you're going with this. 59mm can bolt to stock non-ported 3400 manifold. 65mm requires porting, or you can switch out to ported intake or 3500 upper. if you want a 68, you have to have the 3500 upper. This decision also should also take into account whether or not you'll be doing a 3500 swap. Chances are if you've never had your intake gaskets changed, they will be leaking. If they are, this would be where we used to recommend people go with the 3400 ported upper and lower intakes at the same time because it's a great time to fix the problem and also put on better parts. Now though since we started doing 3500 swaps, we have this rule of thumb regarding 3400's and gasket leaks ... if the 3400 is only leaking at the intakes and not the headgaskets, it's ok to just change the intake gaskets, but if there is even a chance it needs headgaskets too, you might as well just do a 3500 because you are going to get a lot more for the money. So in my opinion, these are your choices (prices do not include core charges)...
1)59mm on stock intakes - $140
2)65mm with ported upper (tb inlet only) - $315
3)65mm with ported upper and lower (includes all gaskets) - $540
4)65mm with 3500 upper intake - $455
5)68mm with slightly ported 3500 upper (if you buy tb and intake at the same time, we do this porting for free) - $475

If you choose 4 or 5 from that list, they include $100 worth of the parts in our 3500 swap kit, so if you ever do the swap in the future, you will already be part of the way there.

For me, the 3500 is the way to go, so that's why when I put these mod lists together, I also choose mods that are transferrable to the 3500. I don't suggest intakes, heads, etc to people until they know for sure which engine they'll have.
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1999 Z34 - 3800 Turbo - Under Construction
1999 Grand Am GT Turbo race car - 12.1ET on stock engine with 10psi!
1977 Corvette - LS1/LS6 T56 - Under Construction
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