Which cam and other questions

[TexasRed]

OK. Seems the neighbourhood association around here may send me a "notice" from what I hear on my pickup even though it's sitting in the driveway, ain't hurtin' nobody waiting for an engine. Which when I get it in may be the time I pack everything up and move to Austin or Atlanta. Grrrr.

Anywho. I've got questions. Which cam do you think would be best for this engine/drive train. I believe it's a 3.42 rear end (it's an '84 shortbox that originally came with a th350c), it's now got a 700r4. I've got a 383 I'm grinding the block on now. The compression ratio should be around 9.3-9.6:1. Vortec heads clearanced for some more lift. For now, just to get the beast rolling, it'll prolly keep the exhaust manifolds it has but it is a dual exhaust with glass packs. Keep in mind, I may like to go back to daily driving this. I'd also like some decent mileage on the highway. Four barrel carb.

http://www.summitracing.com/parts/SUM-K00052/

or

http://www.summitracing.com/parts/ISK-CL201264/

The summit's cheaper and I could get it fairly quickly.

The other question would be, I haven't purchased pushrods yet, but can I get some decent ones at the autoparts store? I'm not sure what length and such. The heads have been milled every so slightly to get a more compression out of them. I think I have pretty much everything else, except radiator and heater core, but I think the four core radiator that autozone has may be the ticket. Thanks for any help!

[eventhorizon66]

I like the Isky between those two because it is on an LCA that is closer to the optimal.  But you'll have to decide how much you want to spend and how much you care about squeezing power out of your engine.  Using a cam that is 5° too wide on the LCA can cost 15-20 ft-lb everywhere in the rpm band and a NA 383 with most performance heads currently available tends to want a 106.

Call Lunati and see what they charge for this cam (you have to call it's not in their catalog):

DV266-06HFL

266/266 seat duration - 217/217 @ 0.050" - .484"/.484" lift with 1.6:1 rockers - 106° LCA - 4° advance

Oh, and I would not use the springs Lunati recommends (73943).  I think they give way too much over the nose pressure @ 331 lbs for this cam.  Shoot for around 105-115 seat pressure and a max of 280 lbs over the nose if you want it to live.  And be sure to check for coil bind (a guaranteed killer of valve train components).

Also, you could go a step larger and still have a very docile street 383, but I wouldn't unless you know you won't be using those manifolds for long.  Stock exhaust manifolds and high performance cams don't mix.

If you are losing the headers but still want monster low end torque and a very good idle this would be a good cam (install it 4° advanced):

http://www.summitracing.com/parts/ISK-201271-6/

[eventhorizon66]

I should also mention that the cams I posted above are medium intensity cams.  They are in line with the cams you posted.  There is more power in a higher intensity cam (faster ramps/more lift), but the risk of wear/break-in problems rises.  I think high intensity cams are the best choice power-wise, but I would only run one if it was nitride hardened.  That service costs you about 100 bones but just about guarantees a long cam life provided the appropriate spring is used.

I thought we'd had this discussion before.  Just found it again:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=12203.15

So you decided to have the heads machined in lieu of beehive springs?  And the block is cleaned up and coming along?

[TexasRed]

Yeah, we did discuss it before. There's some good springs on there, I forget the rates but I think they're the rating for the 270 megacam from isky (pretty much a high performance spring). The block is getting clearanced and soon I should be able to watch everything spin without hitting or getting too close to something else.I had the heads gone through by a performance dude and he got some good springs in there.

There's also this:

http://www.summitracing.com/parts/TFS-K31401000/
OR
http://www.summitracing.com/parts/SUM-K00172/

I'm afraid of the summit cam being too much for a truck though. I mean there's prolly enough compression there and if I install it a few degrees advanced, maybe I can bring the power curve down some. Is there a way to find the gear ratio without pulling a cover? Is it stamped on the diff somewheres?

[joesgarage71]

 Which ever cam you chose it needs to be a small base circle cam for the 383

[eventhorizon66]

Which ever cam you chose it needs to be a small base circle cam for the 383

Not necessarily.  And unless the rotating assembly is already balanced I would grind the rod bolt heads to clear the cam before running a small base circle.  A small base circle cam will exacerbate wear issues on a flat tappet cam.

[joesgarage71]

Which ever cam you chose it needs to be a small base circle cam for the 383

Not necessarily.  And unless the rotating assembly is already balanced I would grind the rod bolt heads to clear the cam before running a small base circle.  A small base circle cam will exacerbate wear issues on a flat tappet cam.

Is that what ARP recomends grinding on there bolt heads. The ONLY grinding that should be done is in the oil pan rail area to clearance the block.
If you break in your cam the right way wear issues shouldn't be a problem, unless you use some of that offshore crap(lifters)

[eventhorizon66]

I'm sure ARP frowns on it, but I don't care.  Don't get me wrong, it's definitely possible to screw up the rod bolts royally if you aren't careful, but for minor clearance issues it's perfectly safe.

Certainly the best solution is the use of stroker rods which have the lowered shoulders and cap screws to clear both the cam and the block.  But there is no good reason why the ONLY place to grind is on the block (that can get you into trouble too if you aren't careful).

TexasRed: I would seek a experienced professional opinion in this matter, if it concerns you.  Consult the machine shop you have used and the one you will use should things go wrong.  They may very well tell you to go with a reduced base circle cam and non-clearanced rods.  This forum is a great way to bounce ideas/opinions around, but you are on your own when decision time rolls around.  I'm just stating what I would do.  There's my disclaimer.

[TexasRed]

The rod bolts were clearanced by PAW. It's a balanced rotating assembly. I only grind the block and pan rails, yo. I'm kinda leaning towards the trickflow cam. . . . . .doh!

[eventhorizon66]

Well if the rods are already clearanced, then the work is done for you.  No more need to squable over that.

What has you leaning towards the trickflow cam?  Single pattern cams tend to make more low end torque and thus get better gas mileage, according to David Vizard.  The idea that vortec heads NEED dual pattern cams to make good power is not true, unless you are primarily concerned with top end numbers (as the magazines are).

[TexasRed]

I think that summit cam K00052. I think the power range is a little higher up there than they say. I think I'd rather prefer the isky cam but Oct 2 to ship. . . .YIKES. Hopefully I'm starting the engine on the stand 'fore then.

The trickflow cam just cuz if it was a single pattern would be good. Plus I'm still running unported manifolds.  I've read page 98 too. 

[eventhorizon66]

I've read page 98 too. 

Cool, so you bought the book.  Well if you've read it, you're already a cam expert.  Did you see there is a new edition.  Everything has been updated and it includes 7 new builds (the first three remain the same).  I just got my copy not long ago, and I'm still looking foward to reading it cover to cover (so far I've only picked through the cam and cylinder head chapters).  BTW the cam I mentioned earlier is a grind that David has spec'd and teamed up with Lunati to produce on a special order basis.  It's all in the 2009 edition.

Check out "Cam School" here: http://www.motortecmagazine.com/ (Warning: new website under heavy construction)

[TexasRed]

I can bet that's a lot of money to spend to get a little closer on power generation. Plus what's the business about Post-87 roller blocks needing the appropriate snout for the thrust plate? I have a vortec block, I thought I could just put a flat tappet cam in there and be okay?

[eventhorizon66]

87-up blocks have accommodations for a thrust plate on roller cams.  To use the thrust plate the cam must have a stepped nose.  But this only applies to roller cams.  All (properly machined) flat tappet cams have a slight taper ground into the lobes that keeps the cam pushed back into the block.  Any flat tappet cams will fit any gen 1 SBC.  Just be sure you use an early timing chain because the later roller timing chains are machined to accommodate the thrust plate that you won't be using.

You should also know that because you have a late model block, retro-fitting a roller cam is much cheaper.  If the budget allows that is something you should seriously consider.

[TexasRed]

Unfortunately, the budget doesn't allow it . Well, looking at summit's site, I can get the cam and lifters separate shipped on Monday (for quite a bit higher) but if I want the kit (cheaper), it'll be october 2nd. OR I can order the cam and a different company's lifters. They're having a sale:

http://www.summitracing.com/parts/CRN-1410/

are these fairly quiet?