cam questions

[let-r-eat]

What compression ratio? Just saw in the thread above you thought 11:1? What chamber size on the two? The 230 is the better head. Way too much cam for a 383 at 11:1.I would try to get 13:1 with the darts. 252 intake .620 lift or so. 258 exh .600 lift or so. 107 on intake centerline with 109 LSA. Use a lobe with as much area on those numbers your rockers will stand.

[sj valley dave]

When we ran the 14:1 360 we used Dart 215, angle milled with 2.05 and that Crower cam, but turned it 7800 rpm with a 4412...We used a 13:1 377" with Dart 230's with 2.08 intakes, but it had a smaller roller ion it and it pulled hard to 8200...Used it for the end of season "open" races in CA...Trying to limit the RPM's to 7200 is going to be tough as Perfconn mentioned...It will be hard to get the grunt out of a 383 with only 11:1 compression and be competitive with the WCSS cars...

[perfconn]

The reason I say to keep the 360ci-4412 guage legal engines to 7200-7300 is simply the numbers.You can figure the air requirements of any engine by using the following formula:ci÷2x max rpm÷1728 therefore- 360ci devided by 2 equals 180 times 7200 equals 1,296,00 ci per minute.To get cfm divide that by 1728,which is how many ci is in a cubic foot,which is how carburetors are rated.You end up needing 750cfm for a 360ci @ 7200 rpm.So you see that even at 7200rpm the 4412 which is rated at 500cfm is really not enough carburetor.A Holly 4412 is exactly half the size of a Holly 750 so everything being even it should only be rated at 375cfm.
This is not revelant to the original question but very helpful in classes where carburetor sizes are dictated by rules.

[propit21]

perfconn WOW you got this stuff down to a science. Thanks for the help. another quick question is there any place or any way to tell what a cam is if you have no paper work on it? can you send them to a company to copy the cam or do it yourself? hope you understand what am asking,

[perfconn]

You need more rpm to go with the cam you have or use a smaller cam if your going to keep the rpm low.I don't use anything but Comp Cams and yes they have what is called a cam doctor.They can tell you everything about any cam except the valve lash.Usually cost about $50.00,another reason these dummy engine builders don't need to waste their time grinding the numbers off a cam.

[propit21]

ok thanks we have a back up motor with a cam in it that the driver really likes but don't have any specs on that cam. Also the driver just informed me its a 12.1 compression on the 383 if that makes any different. So what RPM range are we looking at here with our set up to get this thing to shine a little better?

[perfconn]

If you get the rpm up to 8100 or so at the end of the straights you will be a lot faster.One thing you have to watch for is when you get the right cam and the right gear the car will be a lot harder to hook up off the corners.You will find out that setup and throttle control are vital.

[propit21]

Update the 383 runs great with the 220 worlds with the 109 cam in it, we been running 7500 rpm and its got plenty or power thanks everyone..

Now for some more questions and help. We are working on getting our other motor together with is a 355 with dome pistons with 6 inch rods on lightweight crank.

First top end choice is worlds sportman heads 200 with 64 cc cambers with a match bowtie intake, cam engine guy wants to run is crower #00313 @.050 264/268, RR 1.6/1.5, gross lift .597/.570, LSA 106 this is going to be with a 750 cfm gas carb

Second top end choice is dart 215 64cc cambers with victorjr intake with crower cam #00308 @.050 252/260, RR 1.6/1.5, gross lift .565/.549 LSA 105

What is a better choice of the two or what would be the best combo if someone wants to share.

We may in the distance future run IMCA stock car, could we get away with a edelbrock #2701 and a 350cfm carb on this motor with either one of these setups?

thanks

[sj valley dave]

Propit...We had a 360" deal with dart 215 heads with the 2.05 intakes, used the 00308 Crower with a 1.7/1.6 rocker combo with a gauge legal Willy's 4412 and Super Victor and it made 463 HP and pulled hard to 7800...I had spoken with Bill H when building this one and he suggested the parts and pieces and it worked...Still have the engine...It's for sale if you know anyone looking for a great engine...It's not a dedicated 2 bbl deal...Ross/Carillo/LA Billet bottom end..

[propit21]

yeah dave that is where i got the idea of that cam is from what you posted. Sounds like a pretty good engine package. Do you think it would work a 350cfm carb and different intake?

Is that combo snappy or would it be a good dry slick motor?

[sj valley dave]

Not sure about a 350 cfm...with the 4412 it was real snappy all the way up...of course we ran DB back then...we had just gotten off the softs and gotten on mediums....Call Steve H and pick his brain..LOL