Can anyone recomend a decent cam with a nice muscle sound to it (fairly good idle)? I could really use some suggestions here.
This motor is going to be for my daily driver in my 68 chevelle and i want to run it on pump gas. I guess im needing torque more than higher end HP, but thats fine... torque moves weight!
Im going to get an air gap intake for it soon, but im not made of money at the moment and the torker intake should work for now... i also took the advice from a different post about getting 1 3/4" headers.. Thats done.
So here are some specs about my car and motor: The car has 4 speed with 3.08 10 bolt in it. Oversized rear tires (if that matters). The block(minus the current cam) is a 1970 402 (bored 40 over) 2bolt main, high volume oil pump, new clevite bearings, rings, stock pistons (they have about a 1/4" high dome on the top with valve reliefs), and the heads are closed chamber cast iron heads (92 cc i think). It has edelbrock torker intake with holley 670 carb also.
I hope someone can help with suggestions, and maybe any advice because im new to this...engine building.

Thanks,
Bubba

if you plan on running this car in the winters of washington think twice about that air gap manifold. do not go over 230 at .050 for duration and idle will be decent, stay with 114degree lobe seperation also if you have power brakes or a/c

And you'll want a fairly short duration cam puling those gears, given what your compression might be, so a wider LSA would be a help there to. Helping that is, run a fairly short cam, with good compression and pump fuel.

A dual plane manifold would be a help over the torker.

The tall tires make the 3.08s seem even taller, so it akin to pulling a 2.73 gear. This makes off idle starts harder.

Bubba, it's d real nice to know the exact compression of the motor, but it doesnt sound like you have any of the specs written down?

http://www.holley.com/HiOctn/ProdLine/Products/IEC/IECC/Chevy7.html

The 302A3 and 302A4 look about right.

In another post, grn69chev computed that i am about 9.8 up to 10.2 CR. So id say 10:1 is pretty accurate. I dont know how to figure out the true com ratio..

No way to be sure unless the motor was apart.

Can't get the exact CR unless you know the exact piston installed, measured the piston/deck ht., have the head gasket number and actually CC'd the heads. The range I gave you is based on what most guys wind up with, unless they actually try to build a high CR motor. You would have to cut the CC heads about .030 and have the valves in the original ht with no combustion chamber work to get the 92CC from an early head. You would also have to had cut the block deck .020 to get to "0" deck. If you actually did this then you will be able to find out exactly what you have because you should consider laying clay on the psitons and checking for piston/valve clearance - which means disassembly anyway!

hey grn69chev, i finally have had my compression figured to 10:1 so i bought that crane 286 powermax cam that you recomended and installed it. Its almost ready to be dropped in and being my fist moror, i am pretty nervous/anxious... tese normal feelings?!
bubba

As long as you lubed the cam & lifters with plenty of the Crane assembly lube, prime the oil pump, have the timing set correct (close) and prime the carb if needed, you will not have any problems. If the motor doesn't fire up right away,(4 - 5 rotations) don't keep cranking, stop and find out what is wrong with your initial setup. Make the adjustments and try to fire it again. I can honestly say I have never had any problems with a Crane Cam. The lobe lift rates are good, yet not severe to promote cam wear. I think you will be happy with your choice.

Imho, a 286 cam is too big for you..

Go with a Crane 272H10.. I say this b/c of your gears and tires....

But it's your motor so please do what you think will work for you...

pdq67

OUCH! just when i thought there was hope...

this is the second cam that i have bought brand new and now theres doubts?! what am i to do?

Go over to Pat Kelley's great Dynamic Compression Ratio Site and read up on this as well as the ROSS Racing Pistons site and run some CR. calculations throught it so you will get a feel of why we pick cams like we do knowing it's a low compressioned street motor.. (I.e., about 10 to 1 CR. and below)...

Have fun b/c it's a hoot to me...

pdq67

PS., it's all in the intake valve's closing point with respect to CR and pump gas octane...

Bubba,IMHO,you'll be fine with what you have..I have a 396 laying around with approx. the same compression and a much bigger cam (240/246 @.050 Crower solid) and it runs very well.

I'm saying that he's leaving alotta low to mid range power on the table that will make his high-geared ride easier to drive..

Plus, the cam he has will tend ta be harder on his cluch b/c of lack of bottom end grunt, imho... That's all..

But it is your ride so please do what you feel you can live with..

pdq67

So if gearing is a problem, what are some changes i could make that would allow the new motor to ride well? I have 3.08's in back but have a 12 bolt 3.55 availale... would that help out? maybe smaller tires?

3.55's will definately help a 286 cam, imho...

Go for it!! Just expect poorer gas mileage later then your 3.08's will give you...

But again, your 10 bolt probably won't last long if you hammer on it unless it is an 8.5"er vs the older 8.2"er......

pdq67

Definitely go with the 12 bolt and the 3.55's. The 286 cam makes plenty of low end power. I had even thought of going to a smaller converter to kill some wheel spin. I ran a 272 in a an 8.5/1 454 motor before, Crane rates their cams a little different at the seat. A Crane 272 will be close to detonation prone. Go with enough cam up front, you are will wind up changing the rear axle later, no matter what guaranteed.