Fei

Ok I'm starting my first engine rebuild. I don't really know a lot about cam duration in relation to compression and the like. So any info you are willing to toss out would be much appriciated.

Ok now for the question. I have a 76 350 block. I have flat top pistons and was going to go with either 69cc ot 64 cc heads to get just under or just over 10:1 compression. As of right now the bottom end will be stock. I'm getting all new valve train and pistons and heads. I'm running a Tremec 3550 and a 3.73 Posi.
I plan on making this my fun car so streetability isn't a big deal. It's going to have a roll cage 5 point harnesses and no back seat. Just a fun weekend/racecar. Oh and I'm going to be getting long tube headers and 3" exhaust. What kind of cam would you all recommend?

Thanks in advance and if I seemed a little confused that is because it is all jumbled in my head. I'm really excited LOL

miker61588

i have had good luck with the comp cam xe268. you might wanto to check that and make sure that it will work with your setup.

JakeJr

CompCams has a toll free Tech Line. Give 'em a call, tell them all the specs and mods of your engine and what your intentions are. They will give you a camshaft recommendation.

The phone # is on their site www.CompCams.com I believe it's 1-800 CAM HELP.

Then post all the details here and we can kick it around some more.

Hope this helps.

Jake

hydric

with gears like that and a nice 5-speed u have, a set of 69cc heads, you should be able to run a lil bit more duration cam to shift your power rpm range to something higher.

I won't say what cam to get cause that will start a riot (silly people) but I do know with a manual, nice rear end, heads with good combustion chambers and nice flow, you can move the int/ext duration specs of the cam higher which will allow the car to make power at a higher rpm. Plus give you a more animal like sound. I have a 700r4 with stock posi rear (3.08), therefore my flat tappet cam specs is just a lil over stock specs, and i had a bigger cam in it before and allow me to tell you, it was one of the best thigns i ever done for speed EVER.

Good luck and i'm glad to see your happy about the build..

miker61588

ill just say it. just use the comp cams xe268

hydric

the comp cam almost have the same stock specs that u suggest.

What is your set-up mike? rear end, transmission, if auto whats is your stall? I bet you have a non-built tranny (auto) with stock torque converter with stock stall or a rear end with those gears like 3.73 posi.. Also my cheap $80 summit hydraulic cam is just as good if not better than a comp cam in my view (notice i said IN MY VIEW) plus is like 40 bucks cheaper.

I was just mearly saying he could have a bigger cam with his set-up than your suggested cam, not trying to tell you your wrong, or right for that matter. Plus he said its a fun car, which means he will not have an emmissions check??? Which will further my advice to upgrade to a bigger cam..

=]

miker61588

my setup, i currently have a different cam

cheap wolverine blue racer cam from advance auto parts
new cam specs are 234-244 dur .488-.510 lift 110lsa

miker61588

i agree with the bigger cam idea. but not without a better stall converter.

Fei

Very cool guys. I will give them a call next week since I'm heading outta town for Halloween. Could anyone point me in the right direction for a good read on cams and lift and how they affect other parts E.G. timing, compression, ETC.

Thanks again now I know where to look

Fei

ok lets I went to comp cams and now I have some more questions? it seems the larger the duration I have the more mid to high end I get but am I going to notive a big drop in the low end. Or will the gain in mid and top feel better... That is on thing I like about the car now. I can be in 3rd at like 30 and stomp on it and roast the tires. Heh I know it is kind of childish but it is so much fun... anyway I just don't really want to lose that off the line power. This is only going to be an occasional drag car, mostly weekend fun. :lala:

hydric

Well mike, he don't have a automatice tranny, a Tremec 3550 is a 5 speed manual (no?). and what I was asking you is what set-up did you have whenever it was you ran the comp cam (rear end gear ratio, tranny, heads etc).

I use the summit cam, friends use the summit cam, no compliements at all. My brother recommend the summit tappet cam when i went to him, he worked at a machine shop building sbc's amongst others for years and his boss built them for years n years before he was even born. Don't know about you, but i like to save money and have a nice perforamce product =]

Fei, personally I would call your local machine shops/the folks at summit racing or from what I hear, the folks at comps can give you good info on cam selection. Also, what better place to read on cams then right here on thirdgen.org, do a search here, you'll probably find all your lil heart could even desire about cam selection.

miker61588

DOH!!!! MY BAD

that paints a whole diffrent picture. when i first read this post it was 600 am. im not a moring person as you can tell.

miker61588

another thing. im not downplaying the summit cams at all. i have never used one but i will not say that they suck or they are good. i did use PAW cams for years. they are cheap and they work great. the only reason i bought the the xe268 is because so may people say to get it.

JakeJr

There's a relatively inexpensive computer program called Dyno2000. It has an interator function which allows you to plug in some base camshaft timing specs. Then you can enter valve opening and closing points on each side of the base numbers.

The program will then do the calculations and come up with the best specs for your particular combination.

Last time I ran it, I took the base specs of the cam I'm currently running then used 10 degrees on either side of the base opening and closing points and clicked on "Run".

There were over 48 million calculations that the program would make, as it tried every possible combination to achieve the best power (you can have is look for best torque or best horsepower.

Since 48 million would have taken more than a day to complete, I narrowed it to 5 degrees on either side. Cut the number of calculations dramatically.

Nice little program to see what changes give what kind of results.

The projected torque and horsepower numbers maybe off from what you'd actually see on a dyno by a small amount (maybe 10 percent or so) but the program will show you which direction to move in your search for more torque/HP.

Hope this helps.

Jake