The car setup would be as follows: A 1968 Skylark with 350/TH400, this car would be at full weight (no fiberglass or lexan pieces) Block milled .30 over with forged 10:1 pstons Mild ported and polished stock heads with dual valve springs and TA 1.6 roller rockers Aluminum TA intake with a reworked Q-jet 100-150 HP shot of nitrous Shift kit in the trans 3200-3500 converter Strange engineering S60 rear with 3.55-3.73 gears Here is the cam in question: http://www.taperformance.com/proddetail.asp?prod=TA_510-350 I like the fact that it is slightly bigger on the exhaust duration to work well with the spray. My concern is working with the vehicle weight and the gear and converter sizing. This car will see very limited street miles (MAYBE 200 miles a year) and will make its home at the dragstrip. Thoughts??? Chris
HI there. Call finishline and ask for Bob, he can set you up with a custom camshaft. http://www.finishlinemotorsports.com/ Being that you are running nitrous there are no off the shelf cams that will work well for the RPM range you are going for.
Rpm range for me is looking like 3500 to 5500 with a 5800 max. I figure anything with more exhaust profile will help scavenge and work well with a small dose of spray. I will check them out. ---------- Post added at 11:44 AM ---------- Previous post was at 11:39 AM ---------- Is there any 350 nitrous cams out there? I haven't seen any other than having a custom camshaft made.
I donated a lunati cam to a guy who ran 12.5 with a 125 shot on a 15.9 second 8:1 worn out stocker. Lookup nick a and u will find the info on the cam. But I still say that a custom cam is Way better
If you spend Alittle more on porting and big valves you won't need as much cam. Maybe the 413 then with 3.90 gears.both cams really need more compression. I would make sure you measure piston depth.you might need to mill block to get the 10 to 1 that you are looking for and I would try for 10.5 with either cam. 350 blocks are not always at correct height from crank centerline for compression to be correct.
Yes, in some of the reading I have been doing I am seeing that about the 350 blocks. I figured with the 10:1 pistons on the stock block I would be between 9.75-9.90:1. Heads will be ported and polished as well as some 1.95 1.50 high flow valves. was thinking going over the 10:1 with the spray might be suspect and keeping with the forged pistons might even let me bump the shot up a bit as long as the ring gaps are set right, but I am not opposed to decking the block if I have to.
Thank you for the input everyone. As funny as it sounds my only nitrous tuning experience has been on modern fuel injection motors. The cam profiles are so much different. This is the one part of it I'm not 100% about.
The link I posted above about the guy running a nitrous 350 Buick using a Lunati cam is a proven cam to work well in this engine. If you want an off the shelf cam that will LOVE the nitrous then the lunati is a safe bet. This cam in a stock worn out 8:1 350 ran 15s in the quarter mile and 12.5 with nitrous so it is a good profile for nitrous. If you want to make the best of the combo then a custom flat tappet cam will get you a bit more than an off the shelf cam, and it is not too much more money to go this route... This way you just provide the specs of your engine and have the cam grinder make you a cam to suite your needs. If you go this route I would get the heads ported and the engine built first so that you would know your head flow numbers and compression ratio. Tell us more about the pistons you are running? Is this engine built already or are you still looking for pistons?
As everyone else has suggested, a cam with more exhaust emphasis is your friend when pushing more fuel/air in the intake through whatever means (forced induction, nitrous, massive carb CFM, fuel injection, etc.) on the Buick 350. More duration and lift. There's some info floating around here about the Buick 350's innate head flow design and its strengths and limitations that may give you some more insight. Don't build it like a Chevy and you'll be fine. :TU: The Lunati cam Sean suggested would work fine, though don't expect it to last a long time. Being a track car you should be fine with it though. I checked out the specs on it and here's a brief analysis: Lunati 33204 .468/.492 lift @1.55 215/225 dur @.050 = 0* overlap 265/275 dur @.006 = 50* overlap 110 LSA Lobe intensities 50*/50* I/E Seems to be a symmetric cam on lobe design (most are, because they're simpler). Idle should be fairly smooth, with maybe a hint of a lope. Should have pretty decent vacuum, somewhere around 14-16" or so. Important to note is the valve timing events (I checked those out while calculating overlap) @.050 is almost exactly like the Crower level 3 camshaft, at 33.5* IVC and 46.5* EVO (the crower cam is 33/46 respectively) while the IVO and EVC are at 1.5* apart from each other, cancelling themselves out for 0* overlap @.050 (which is different than the Crower level 3, with -3*/-6* respectively for a total of -9* overlap @.050). You may need to check piston to valve clearance on this cam if you decide to zero your deck. Basically, this cam will give you a bit more power than the Crower level 3, but at a cost. It'll wear out faster and not be as efficient on gas, though again, if you plan on using this car as a track car, won't be a big deal. So this Lunati cam and the Crower level 3 cam are similar in design intent, with the Crower being milder and better suited for street use. Maybe this will help more than confuse. Best wishes! Gary ---------- Post added at 01:29 PM ---------- Previous post was at 11:37 AM ---------- Also something to keep in mind: cam choice isn't as imperative as one may think when adding massive amounts of other power in the form of add-ons, like nitrous, boost, etc. as long as the cam follows certain parameters the hair-splitting isn't as crucial. This is because the amount of power gained from switching camshafts over a stock camshaft, particularly with smaller cubes, isn't that big of a difference in terms of power gained, though the cons will become evident after a few thousand miles (or 10s of thousands, depending), which may not be a big deal to some. However, we're talking what, 5? 10? 15? extra HP? ratio wise, this is a very small improvement over the factory numbers. You can, however, gain better results when combining it with other parts that compliment each other for an overall gain of 20-30+ HP over a bone stock engine, which is (more) noticeable. But adding 100-150 HP nitrous will make those other improvements seem pretty insignificant, unless you're struggling to squeeze extra tenths or hundredths of seconds out of your combination. To me, the engine's longevity and stability is far more important than squeezing an extra 5-10 HP out of it with a cam that'll wear out 10x faster, but whatever floats yer boat. To put it into perspective, a stock Buick 350 with 300 HP at the flywheel that gains 10 HP from a larger, valvetrain chewing cam profile, has gained a whole 3.33% power. You can gain or lose more than this depending on the weather that day. Properly setting up the camshaft to match the airflow characteristics of the heads will net better success. Increasing the quality of the airflow is key. To me, increasing lift and durations so that the lobe will fall within the sweet spot is just 'throwing a cam at it' in hopes it'll perform better. There are better ways to improving the existing airflow while not crippling your efforts by having the engine working against itself. Bottom line is, the intake runners won't flow much past .400 lift, even with some porting, and exhaust gains a very small amount past .400, so increasing it some past that is ok, though we're only talking a couple CFM or so on mildly ported heads. Unless you hog out the heads for the sake of flow numbers, the heads work best with a camshaft that has lifts below .450, plain and simple. High lift cams that perform well do so because of their durations, LSAs, ICL, lobe symmetry, etc. Shave .050 lift off those cams and you'd see very little difference in performance, though they'd probably last twice as long just by that one simple modification. Hogged out heads will benefit from higher lifts, obviously. Aluminum heads with much improved runner designs and greater flow numbers at higher lifts will see tremendous benefit from high lift roller designs, even with relatively low durations. So the cure for the stock head is to make the air flow as best it can at lower lifts, and is accomplished with larger valves, runner cleanup and contouring, and asymmetrical lobes with lifts/durations to match head flow. More info on all this is on other threads here. Gary
Can't go wrong with a custom ground roller cam,like Sean said figure out what your static compression will be and the flow numbers of your heads after they're ported. Tell the cam grinder that info,plus the nitrous of coarse,what gear you're going to run and trans and whatever other info they ask for. When the S/P intake comes out you'll be able to up the nitrous to a 500 HP shot if you want that much,so keep that in mind also. Dyno info of the engine will be helpful to have a torque converter made,so keep that in mind too. The faster you can make the car without nitrous,the faster it will be with. I wish you the best of luck,and have fun racing you Skylark! Derek
I think this is going to be the way I am going to go to start with. Lunati 33204 .468/.492 lift @1.55 215/225 dur @.050 = 0* overlap 265/275 dur @.006 = 50* overlap 110 LSA All of this info is exactly what I was looking for. I am not as worried about the cam lasting forever, but a couple of good seasons would be just fine with me. I don't think I am going to end up decking my block. I think what I am going to do is ditch the iron 74 4 barrel manifold I have for an aluminum Poston piece. Do this cam listed above along with an oil pump rebuild with regulator, and a new timing set. As far as the heads go I was thinking some aftermarket high flow valves and some porting along with a better set of rockers, pushrods, and springs. Re using the stock rods and crank with the 10:1 forged (advertised) pistons. Tune it all up NA and then add the kit and re tune it. The trans will be stock with a shift kit and a converter. For this I am thinking a 3200 stall with the anti ballooning plate inside. I am not too sure yet weather this will be a custom piece or off the shelf yet either. The rear as stated above will be the S60 bolt in unit and I am leaning with the 3.73:1 gear set. Front and rear coilovers with tubular control arms front and rear and the 4 wheel disc conversion. All of this on the 15X8 Weld Alumastars and some slicks. I am pretty sure there is some room for improvement on this engine from here, but doesn't it seem like a good start? This is going to be somewhat on a budget so I am trying to spread all of this out from now till April. None of this work has been done as of yet other than the 400 rebuild with the shift kit. My 68 only has 46,000 miles on her so everything is basically stock. Oh, there has been an HEI conversion done as well, but that is it. I am still going to do some more searches and lots of reading, but I do appreciate everyone's opinions and suggestions. They are very helpful, Thank you!
Glad I could be useful. Plenty of other people here too with lots of good info and advice. It's always good to get everyone's views on something then make your own decision.:TU: I like to play things on the safe side, so keep that in mind when reading my suggestions or comments elsewhere. My suggestions are generally toward milder applications and longevity and durability subjects. My literature is probably boring to most people, but that's ok with me--as long as it's down as reference, there may be those out there who can put it to use. I can get a bit long-winded too, so I apologize if it's stressful to read. Gary
I don't find it stressful at all very helpful actually. I apreciate people taking the time to help me and give me ideas or advice. I really want to go out and really surprise people with this setup. I am going to attempt to hide the spray in an attemp to keep it as stock appearing as possible too lol
Well to be fair, the lobe intensities can be higher (lower number=more intense) today than decades ago, because of a nitride impregnating method used on the surface of cam lobes to make them much more resilient and slicker, so 50* isn't terrible. I just like 60* or more, though anything from 55-60 is said to be sufficiently durable enough. Some cams out there have less than 50*, some dipping into the mid 40's. These cams tend to perform better, though they're rougher on the valve train geometry and things tend to wear out faster with them. That's no biggie for people who mainly use their car as a source of entertainment though, but it's still nice to know in case you wanted to use it as a daily driver here and there and put some miles on it. This just applies to flat tappet designs. Roller cams don't have this problem and can have lobe intensities much higher than this and still outlast the flat tappet cams. Roller cams are way more expensive, but it's worth it if you have the money. Gary (EDIT: cam manufacturers won't put in the cam's description "rough on the valvetrain" even if it is...bad for advertising business I guess lol. Though if the cam is 'easy on the valvetrain' they'll be Johnny on the spot with putting that in there. I'm just Honest John I guess. Always best to be a straight shooter so people know what they're dealing with up front.)
Do you have the weld wheels already?I have a pair of weld pro stars 15x8 with 5 in backspace should be right for 68 -69 body's has holes for bead screws already. Had on my regal when I had 12 bolt rear. If you are interested
Hell yeah I'm interested! Lol can you post up some pics? ---------- Post added at 07:35 PM ---------- Previous post was at 07:31 PM ---------- I think a custom roller cam is in the cards for the future but for now I am kind of liking the idea of that lunati. This gives me room to improve upon the setup and tweak things. I get where you are coming from with the ramp rates and hardness changes. Technology has changed so many things in alot of ways.
Also if you could pm me with a price shipped to 98373. Thanks again. Btw see you are from Bridgeview. ..I'm from the Chicago burbs lived there till I joined the army.
