just looking for thoughts and suggestions what i have so far c5 vette wheels/tires, 373 4th gen rear, tubular rear control arms and panhard proline springs (rear), 383 shortblock, with a mystery cam cant make out the numbers on it but can tell its pretty big when setting next to a crane 270 compucam

plan is for a t56 and aftermarket efi maybe a commander 950 a friend has it on his vette and likes it and hey are not terribly expensive now and that is a factor as i am a broke college student with 2 kids and an x-wife and work as a security guard am leaning toward a front end kit from p.a. racing with the k member and everything and 2 inch drop spindles but am totally undecided on heads

so i guess my primary thought is what heads would be good options besides obvious stock or vortechs and so far eveything on the car is previously owned except for the pistons that were not with the 383 (replacing them cost me more than the basket case motor)and any other thoughts or opinions are welcome as well

 

How so?





Which of these 2 cams would be considered "bigger"?

That's around $4000 worth of stuff BEFORE the heads; do you have a budget and a time frame for the heads?

 

would not even guess off the pics on the cams i had the two setting side by side and yes i understand eyeballing it is in no way accurate and i admit to no expertise in that area but the lobes on the mystery cam i have were simply visibly larger than on the crane that i have the numbers on however part of that is also the crane is a flat tappet and other is a roller and no set budget just the more i spend the longer till it gets finished would like to have it driveable by spring/summer so k memeber may be put off a while would like to keep heads at around 1k less is better but i dont want to be redoing it in a year either

 

Wel, both of the cams in the pic are rollers. Which one looks "larger"? Cmon, just tell us what you think.

 

i already did and if you cant accept that i dont know because pictures are deceptive then mail them to 215 n lincoln ofallon il 62269 and include return shipping and i will gladly give an honest answer otherwise im sorry to have robbed you of your chance to poke fun at someone over their statement that you deem ignorant or uninformed and again any thoughts or comments pertaining to my build are welcome

 

OK, nobody's "poking fun" at anybody here. We're trying to teach a lesson in how things work.

THe top cam, with the SMALL lobes, is actually the "larger" one. It's a solid roller with about .600" of lift, on a small base circle, for motors with SO MUCH STROKE the rods would otherwise hit the cam.

The bottom cam, with the LARGE looking lobes, is a mild street hyd roller with just over .500" of lift.

THINK for a minute about the concept of "lift": it's not how "tall" the lobe is, it's THE DIFFERENCE BETWEEN the "tip" of the lobe, and the "heel" of the lobe. The way a cam is made, the TIP of the lobe is made basically as large as it can be and it still be able to slide through the bearings; then the HEEL is ground however much SMALLER than that to create the desired lift. That's why you can almost always have a worn-out cam ground BIGGER, but it's nearly impossible to make one SMALLER.

So if you've got a cam that "look" "big", odds are, it's REALLY "small". Best thing to do to start out, is to mic an intake and an exhaust lobe from the tip to the heel, then at 90° to that (across the "flank" of the lobes); subtract the one measurement from the other, which will give the approximate lobe lift; then mulitply by the "theoretical" rocker ratio (1.5) to give the lift "spec". Getting the duration is a bit trickier, because you need a good way to measure the change in lift, such as by using a dial indicator, while simultaneoulsy measuring rotation such as with a degree wheel; and high precision is necessary to come up with anything accurate enough to be useful.

As far as heads, considering the churn in that business, best thing to do will be to save up at least $1000, then start looking; who knows who will still be in business at that point. Patriot for example disappeared this past October. Unfortunate; but I guess it's a tough business.

 

thank you for the instruction on how to get the specs from the cam i did not know how to do that but i did know that the base circle was a factor of it that is one reason i would not say either way from the pics. it was always my plan to have it specced from a machine shop somewhere before trying to run it in my motor and i figured heads would be at least a grand especially for new ones and probably close to that for used ones
and please if i gave offense in the earlier post I do apologize