ok well im lookin at getting some parts... how do u guys thingy these work together?


RPM Air-gap.
Holly 670cfm street avenger
cranecam 280 w/ lifters

 

What size engine? What gear ratio? What transmission?

Dave

 

350 4bolt-main.
not sure what the gears are and the tranny but its a 3spd manual.

 

Well its tough to give a reply until we know what gear ratio you have.

Dave

 

well lets say that the rearend is stock then i would guess it is 2.73:1 lets just say.

 

That being the case, I'd say your cam is too big. For gears like that, I'd be looking at say a Comp 252H or 260H as the biggest I'd go, so as to keep a good chunk of bottom end torque.

 

well, heres what i did. 350 .030 over 9:1 comp, holley 700cfm dp, 10"3000 stall, crane hyd. .480/.485 230/235 at .050 28x10 slicks, ported 441's extremly under geared 3.42's for those slicks, ran a 13.2 and on 215/70/15 street tires it was a 13.5 no traction at all esp with the converter! ps. my motor dynoed at 375bhp at 5700rpm and 401lb ft at 4200rpm, that was engine dynoed. with the 4.10's and the slicks, im gonna see if i can smash into the 12's with the old combo before i add all my mods. p.s. i was running the traps at 4500rpm wow! lol now with the 4.10's it will be pulling at 5200rpm thats a difference of pulling with 330hp at 4500rpm and 370hp at 5200rpm, should make a big difference in the top end. i see 12's in my future with that combo =)

 

well if i get the 280 and change the gears and what not... whats the difference between chop/rough idle.... i want the 280 but i also want the nice lumpy idle... u all know what i mean

 

My cam is (about) a 280, and it's not all that noticeable as far as a nice lope goes. Of course you can tell I have a cam by the sound, but it doesn't sound like a drag car or anything. I believe the idling characteristics of a cam may not have as much to do with the duration as it does with other attributes. Perhaps the lobe seperation angle or something, I can't remember. Maybe someone here can respond who knows more about it than I do. As far as performance, if the rest of the engine is fairly stock, you probably won't benefit greatly from such a large cam.

 

well when i get the cam, ill also get an RPM Airgap and 670 holly dp at the same time.

 

The Holley Street Avenger is not a double pumper. Holley does not make a 670 dbl pumper. The Avenger is a vac. secondary carb,
and works okay up to about 300HP. I don't recommend it however, for performance work. My buddy hates his and has gone back to a Q Jet. Some on the other hand, like them. Its a matter of personal choice.

If you go for the 'lope', you're going to lose bottom end power. Look at the duration @ 0.50" #'s when looking at buying a cam. If you mismatch your parts I guarantee you'll regret it.

Heres an example: about 10 years ago one of the Z/28's I owned (I've had several over the years) was a 1980 with stock LM1 350, automatic and 3.42 posi. I super-tuned the Q-Jet with modifications I'd learned over the years, and tweaked the stock HEI with a quicker advance curve. I installed headers and a good 2 1/2" dual exhaust with $25 parts store special mufflers. That was it. The car had a shift kit from the previous owner. The car had unbelievable stoplight to stoplight torque on the street. It would lay rubber all through first and screech sideways when it hit second. A guy I knew at that time had a 1980 Camaro RS with a built 350, big cam, etc. His car could not touch mine on the street. The only place his car was faster was at the top end of the tach, and by that time the race was done. On the strip, it might have been different and I dont doubt he would have beat me, but on the street torque is what wins races, makes the car so awesome to drive around, give the best throttle response, and fuel efficiency.

What I'm saying is this: if you want an impressive car, dont get hung up on things like a lopey idle, but rather my advice is to match all your components properly. A big cam will *lose* torque and throttle response down low, and the topend pull wont be enough to offset the loss in the bottom and midrange. Big cams can also be a huge pain to tune the engine, get through emmissions (a whole nuther kettle of fish), and general make your life miserable unless you are revving the engine all the time, hence the need for steep rear gearing.

Decide *exactly* what you expect the car to do, and then plan accordingly.

 

ok i found out that i have 3.42:1

so what would be the best way to go for a cam/lifers, intake, carb.

i was just look at this

RPM Airgap
Cranecam 274
650cfm speed demon

im goin into bestbuy performance tomorrow to talk to russ about a deal.

 

That combo looks lots better. I *assume* that Crane cam has around 224 deg. @ 0.50", so that looks good. The seat to seat timing can be erroneous (ie, '274' or '280' cam) so its best to look at the 0.050" duration.

However, what is your compression ratio?

 

i believe that it is 8.2:1 but thats off of nastyz28, but my motor is a 4 bolt so i can't be sure....

should i go with a crane cam or a comp cam... its just at bestbuy i can get a cranecam /w lifter kit cheaper then i can compcam w/out lifters

 

Yep, you can get a Crane Blazer cam and lifter kit for like $129 or so from Best Buy. Its a good deal. My suggestion here is you get the Blazer 204/214 or 214/224. I wouldnt go any larger, as your compression is too low. Those #'s are the duration @ .050", which is what is most important. If you want my .02, get a Performer intake, the Crane 204/214 cam, and an Edelbrock 600cfm carb. what you'll have there is the Edelborck Performer package. The same cam that Edelbrock markets as their 'Performer' cam, is one of the same cams of the Crane Blazer line, but at a much cheaper price since its not a repackaged part with the 'Edelbrock' name on it. For your combo, I wouldnt go with the RPM or a much bigger cam, simply because of your low compression (bigger cams will give a doggy, low-torque feel in the lower RPM ranges).
The above should give you a crisp, torquey and super streetable throttle-responsive street car. I'd use the RPM if you had more compression and a bigger cam and hence, more engine RPM.

Just my opinion.